Testosteron (2007 Film)
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Testosterone (T) is a
medication A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy (pharmacotherapy) is an important part of the medical field and re ...
and naturally occurring steroid hormone. It is used to treat
male hypogonadism Hypogonadism means diminished functional activity of the gonads—the testes or the ovaries—that may result in diminished production of sex hormones. Low androgen (e.g., testosterone) levels are referred to as hypoandrogenism and low estrogen ...
,
gender dysphoria Gender dysphoria (GD) is the distress a person experiences due to a mismatch between their gender identitytheir personal sense of their own genderand their sex assigned at birth. The diagnostic label gender identity disorder (GID) was used until ...
, and certain types of
breast cancer Breast cancer is cancer that develops from breast tissue. Signs of breast cancer may include a lump in the breast, a change in breast shape, dimpling of the skin, milk rejection, fluid coming from the nipple, a newly inverted nipple, or a re ...
. It may also be used to increase athletic ability in the form of doping. It is unclear if the use of testosterone for low levels due to aging is beneficial or harmful. Testosterone can be used as a
gel A gel is a semi-solid that can have properties ranging from soft and weak to hard and tough. Gels are defined as a substantially dilute cross-linked system, which exhibits no flow when in the steady-state, although the liquid phase may still di ...
or patch that is applied to the skin, injection into a muscle, tablet that is placed in the cheek, or tablet that is taken by mouth. Common side effects of testosterone include
acne Acne, also known as ''acne vulgaris'', is a long-term Cutaneous condition, skin condition that occurs when Keratinocyte, dead skin cells and Sebum, oil from the skin clog hair follicles. Typical features of the condition include comedo, black ...
, swelling, and breast enlargement in men. Serious side effects may include
liver toxicity Hepatotoxicity (from ''hepatic toxicity'') implies chemical-driven liver damage. Drug-induced liver injury is a cause of acute and chronic liver disease caused specifically by medications and the most common reason for a drug to be withdrawn fro ...
,
heart disease Cardiovascular disease (CVD) is a class of diseases that involve the heart or blood vessels. CVD includes coronary artery diseases (CAD) such as angina and myocardial infarction (commonly known as a heart attack). Other CVDs include stroke, hea ...
, and behavioral changes. Women and children who are exposed may develop
masculinization Virilization or masculinization is the biological development of adult male characteristics in young males or females. Most of the changes of virilization are produced by androgens. Virilization is most commonly used in three medical and biology ...
. It is recommended that individuals with
prostate cancer Prostate cancer is cancer of the prostate. Prostate cancer is the second most common cancerous tumor worldwide and is the fifth leading cause of cancer-related mortality among men. The prostate is a gland in the male reproductive system that sur ...
not use the medication. It can cause harm to the baby if used during
pregnancy Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occurs by sexual intercourse, but ca ...
or
breastfeeding Breastfeeding, or nursing, is the process by which human breast milk is fed to a child. Breast milk may be from the breast, or may be expressed by hand or pumped and fed to the infant. The World Health Organization (WHO) recommends that br ...
. Testosterone is in the androgen family of medications. Testosterone was first isolated in 1935, and approved for medical use in 1939. Rates of use have increased three times in the United States between 2001 and 2011. It is on the World Health Organization's List of Essential Medicines. It is available as a
generic medication A generic drug is a pharmaceutical drug that contains the same chemical substance as a drug that was originally protected by chemical patents. Generic drugs are allowed for sale after the patents on the original drugs expire. Because the active ch ...
. In 2020, it was the 172nd most commonly prescribed medication in the United States, with more than 3million prescriptions.


Medical uses

The primary use of testosterone is the treatment of males with too little or no natural testosterone production, also termed hypogonadism or
hypoandrogenism Androgen deficiency is a medical condition characterized by insufficient androgenic activity in the body. Androgenic activity is mediated by androgens (a class of steroid hormones with varying affinities for the androgen receptor), and is dependent ...
(androgen deficiency). This treatment is referred to as hormone replacement therapy (HRT), or alternatively, and more specifically, as testosterone replacement therapy (TRT) or
androgen replacement therapy Androgen replacement therapy (ART), often referred to as testosterone replacement therapy (TRT) or hormone replacement therapy (HRT), is a form of hormone therapy in which androgens, often testosterone, are supplemented or replaced exogenously ...
(ART). It is used to maintain serum testosterone levels in the normal male range. Decline of testosterone production with age has led to interest in testosterone supplementation. A 2020 guidelines from the
American College of Physicians The American College of Physicians (ACP) is a national organization of internists, who specialize in the diagnosis, treatment, and care of adults.Sokanu "What is an Internist?" Retrieved October 20, 2014 With 161,000 members, ACP is the largest ...
support the discussion of testosterone in adult men with age-related low levels of testosterone who have sexual dysfunction. They recommend yearly evaluation regarding possible improvement and, if none, to discontinue testosterone; physicians should consider intramuscular treatments, rather than transdermal treatments, due to costs and since the effectiveness and harm of either method is similar. Testosterone treatment for reasons other than possible improvement of sexual dysfunction may not be recommended.


Deficiency

Testosterone deficiency (also termed hypotestosteronism or hypotestosteronemia) is an abnormally low testosterone production. It may occur because of testicular dysfunction (
primary hypogonadism Hypergonadotropic hypogonadism (HH), also known as primary or peripheral/gonadal hypogonadism or primary gonadal failure, is a condition which is characterized by hypogonadism which is due to an impaired response of the gonads to the gonadotropins ...
) or hypothalamic–pituitary dysfunction (
secondary hypogonadism Hypogonadotropic hypogonadism (HH), is due to problems with either the hypothalamus or pituitary gland affecting the hypothalamic-pituitary-gonadal axis (HPG axis). Hypothalamic disorders result from a deficiency in the release of gonadotropic r ...
) and may be
congenital A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can ...
or acquired.


Low levels due to aging

Testosterone levels may decline gradually with age. The United States
Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respon ...
(FDA) stated in 2015 that neither the benefits nor the safety of testosterone supplement have been established for low testosterone levels due to aging. The FDA has required that labels on testosterone include warnings about increased risk of heart attacks and stroke.


Transgender men

To take advantage of its virilizing effects, testosterone is administered to
transgender men A trans man is a man who was assigned female at birth. The label of transgender man is not always interchangeable with that of transsexual man, although the two labels are often used in this way. ''Transgender'' is an umbrella term that inclu ...
and other transmasculine individuals as part of
masculinizing hormone therapy Masculinizing hormone therapy, also known as transmasculine hormone therapy, or female-to-male (or FTM) hormone therapy, is a form of hormone therapy and gender affirming therapy which is used to change the secondary sexual characteristics of t ...
, titrated to clinical effect with a "target level" of the average male's testosterone level.


Women

Testosterone therapy is effective in the short-term for the treatment of hypoactive sexual desire disorder (HSDD) in women. However, its long-term
safety Safety is the state of being "safe", the condition of being protected from harm or other danger. Safety can also refer to risk management, the control of recognized hazards in order to achieve an acceptable level of risk. Meanings There are ...
is unclear. Because of a lack data to support its efficacy and safety, the
Endocrine Society The Endocrine Society is a professional, international medical organization in the field of endocrinology and metabolism, founded in 1916 as The Association for the Study of Internal Secretions. The official name of the organization was changed ...
recommends against the routine use of testosterone in women to treat low androgen levels due to hypopituitarism,
adrenal insufficiency Adrenal insufficiency is a condition in which the adrenal glands do not produce adequate amounts of steroid hormones. The adrenal gland normally secretes glucocorticoids (primarily cortisol), mineralocorticoids (primarily aldosterone), and androge ...
, surgical removal of the ovaries, high-dose
corticosteroid Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are involv ...
therapy, or other causes. Similarly, because of a lack of data to support its efficacy and safety, the Endocrine Society recommends against the use of testosterone in women to improve general
well-being Well-being, or wellbeing, also known as wellness, prudential value or quality of life, refers to what is intrinsically valuable relative ''to'' someone. So the well-being of a person is what is ultimately good ''for'' this person, what is in th ...
, to treat
infertility Infertility is the inability of a person, animal or plant to reproduce by natural means. It is usually not the natural state of a healthy adult, except notably among certain eusocial species (mostly haplodiploid insects). It is the normal state ...
, sexual dysfunction due to causes other than HSDD, or to improve
cognitive Cognition refers to "the mental action or process of acquiring knowledge and understanding through thought, experience, and the senses". It encompasses all aspects of intellectual functions and processes such as: perception, attention, thought, ...
, cardiovascular,
metabolic Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...
, and/or
bone A bone is a Stiffness, rigid Organ (biology), organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red blood cell, red and white blood cells, store minerals, provid ...
health. A 2014 systematic review and meta-analysis of 35 studies consisting of over 5,000  postmenopausal women with normal
adrenal gland The adrenal glands (also known as suprarenal glands) are endocrine glands that produce a variety of hormones including adrenaline and the steroids aldosterone and cortisol. They are found above the kidneys. Each gland has an outer cortex which ...
function found that testosterone therapy was associated with significant improvement in a variety of domains of sexual function. These domains included frequency of
sexual activity Human sexual activity, human sexual practice or human sexual behaviour is the manner in which humans experience and express their sexuality. People engage in a variety of sexual acts, ranging from activities done alone (e.g., masturbation) ...
,
orgasm Orgasm (from Greek , ; "excitement, swelling") or sexual climax is the sudden discharge of accumulated sexual excitement during the sexual response cycle, resulting in rhythmic, involuntary muscular contractions in the pelvic region charac ...
,
arousal Arousal is the physiological and psychological state of being awoken or of sense organs stimulated to a point of perception. It involves activation of the ascending reticular activating system (ARAS) in the brain, which mediates wakefulness, th ...
, and sexual satisfaction, among others. Women who were menopausal due to
ovariectomy Oophorectomy (; from Greek , , 'egg-bearing' and , , 'a cutting out of'), historically also called ''ovariotomy'' is the surgical removal of an ovary or ovaries. The surgery is also called ovariectomy, but this term is mostly used in reference t ...
showed significantly greater improvement in sexual function with testosterone relative to those who had normal menopause. In addition to beneficial effects on sexual function, testosterone was associated with unfavorable changes in blood lipids. These included decreased levels of total
cholesterol Cholesterol is any of a class of certain organic molecules called lipids. It is a sterol (or modified steroid), a type of lipid. Cholesterol is biosynthesized by all animal cells and is an essential structural component of animal cell mem ...
,
triglyceride A triglyceride (TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids (from ''tri-'' and ''glyceride''). Triglycerides are the main constituents of body fat in humans and other vertebrates, as w ...
s, and high-density lipoprotein (HDL) cholesterol, and increased levels of
low-density lipoprotein Low-density lipoprotein (LDL) is one of the five major groups of lipoprotein that transport all fat molecules around the body in extracellular water. These groups, from least dense to most dense, are chylomicrons (aka ULDL by the overall densit ...
(LDL) cholesterol. However, the changes were small in magnitude, and the long-term significance in relation to cardiovascular outcomes is uncertain. The changes were more pronounced with oral testosterone undecanoate than with
parenteral A route of administration in pharmacology and toxicology is the way by which a drug, fluid, poison, or other substance is taken into the body. Routes of administration are generally classified by the location at which the substance is applied. ...
routes, such as transdermal testosterone. Testosterone showed no significant effect on depressed mood
anxiety Anxiety is an emotion which is characterized by an unpleasant state of inner turmoil and includes feelings of dread over anticipated events. Anxiety is different than fear in that the former is defined as the anticipation of a future threat wh ...
,
bone mineral density Bone density, or bone mineral density, is the amount of bone mineral in bone tissue. The concept is of mass of mineral per volume of bone (relating to density in the physics sense), although clinically it is measured by proxy according to optica ...
(BMD), or anthropomorphic measures like
body weight Human body weight is a person's mass or weight. Strictly speaking, body weight is the measurement of weight without items located on the person. Practically though, body weight may be measured with clothes on, but without shoes or heavy accessor ...
or
body mass index Body mass index (BMI) is a value derived from the mass (weight) and height of a person. The BMI is defined as the body mass divided by the square of the body height, and is expressed in units of kg/m2, resulting from mass in kilograms and he ...
. Conversely, it was associated with a significant incidence of androgenic side effects, including
acne Acne, also known as ''acne vulgaris'', is a long-term Cutaneous condition, skin condition that occurs when Keratinocyte, dead skin cells and Sebum, oil from the skin clog hair follicles. Typical features of the condition include comedo, black ...
and hirsutism (excessive facial/body hair growth). Other androgenic side effects, such as weight gain, pattern hair loss, and
voice deepening A hoarse voice, also known as dysphonia or hoarseness, is when the voice involuntarily sounds breathy, raspy, or strained, or is softer in volume or lower in pitch. A hoarse voice, can be associated with a feeling of unease or scratchiness in the ...
, were also reported in some trials, but were excluded from analyses due to insufficient data. The overall quality of the evidence was rated as low and was considered to be inconclusive in certain areas, for instance on long-term safety. A subsequent 2017 systematic review and meta-analysis of studies including over 3,000 postmenopausal women with HSDD similarly found that short-term transdermal testosterone therapy was effective in improving multiple domains of sexual function. Androgenic adverse effects such as acne and hirsutism were significantly greater in incidence with testosterone therapy, whereas no significant differences in "increase in facial hair, alopecia, voice deepening, urinary symptoms, breast pain, headache, site reaction to the patch, total adverse events, serious adverse events, reasons for withdrawal from the study, and the number of women who completed the study" were seen relative to controls. Although testosterone has been found to be effective at improving sexual function in postmenopausal women, the doses employed have been supraphysiological. In contrast to these high doses, there is little support for the notion that testosterone is a critical hormone for sexual desire and function in women under normal physiological circumstances. Low doses of testosterone resulting in physiological levels of testosterone (<50 ng/dL) have not been found to significantly increase sexual desire or function in women in most studies. Similarly, there appears to be little or no relationship between total or free testosterone levels in the normal physiological range and sexual desire in premenopausal women. Only high doses of testosterone resulting in supraphysiological levels of testosterone (>50 ng/dL) significantly increase sexual desire in women, with levels of testosterone of 80 to 150 ng/dL "slightly" increasing sex drive. In accordance, men experience sexual dysfunction at testosterone levels of below 300 ng/dL, and men that have levels of testosterone of approximately 200 ng/dL frequently experience such problems. The high doses of testosterone required to increase sexual desire in women may have a significant risk of masculinization with long-term therapy. For this reason, and due to the unknown health effects and safety of testosterone therapy, its use may be inappropriate. In 2003, the FDA rejected Intrinsa, a 300 µg/day testosterone patch for the treatment of sexual dysfunction in postmenopausal women. The reasons cited were limited efficacy (about one additional sexually satisfying event per month), concerns about safety and potential adverse effects with long-term therapy, and concerns about inappropriate off-label use. It appears that in women, rather than testosterone, estradiol may be the most important hormone involved in sexual desire, although data on the clinical use of estradiol to increase sexual desire in women is limited. There are no testosterone products approved for use in women in the United States and many other countries. There are approved testosterone products for women in Australia (where it is considered a drug of dependence, medicines that are subject to misuse and trafficking.) and some European countries. Testosterone pellet implants are approved for use in postmenopausal women in the United Kingdom. Testosterone products for men can be used
off-label Off-label use is the use of pharmaceutical drugs for an unapproved indication or in an unapproved age group, dosage, or route of administration. Both prescription drugs and over-the-counter drugs (OTCs) can be used in off-label ways, although m ...
in women in the United States. Alternatively, testosterone products for women are available from compounding pharmacies in the United States, although such products are unregulated and manufacturing quality is not ensured.


Available forms

Testosterone has been marketed for use by
oral The word oral may refer to: Relating to the mouth * Relating to the mouth, the first portion of the alimentary canal that primarily receives food and liquid **Oral administration of medicines ** Oral examination (also known as an oral exam or oral ...
,
sublingual Sublingual (abbreviated SL), from the Latin for "under the tongue", refers to the pharmacological route of administration by which substances diffuse into the blood through tissues under the tongue. The sublingual glands receive their prima ...
, buccal,
intranasal Nasal administration, popularly known as snorting, is a route of administration in which drugs are insufflated through the nose. It can be a form of either topical administration or systemic administration, as the drugs thus locally delivered ...
, transdermal ( patches),
topical A topical medication is a medication that is applied to a particular place on or in the body. Most often topical medication means application to body surfaces such as the skin or mucous membranes to treat ailments via a large range of classes ...
(
gel A gel is a semi-solid that can have properties ranging from soft and weak to hard and tough. Gels are defined as a substantially dilute cross-linked system, which exhibits no flow when in the steady-state, although the liquid phase may still di ...
s),
intramuscular Intramuscular injection, often abbreviated IM, is the injection of a substance into a muscle. In medicine, it is one of several methods for parenteral administration of medications. Intramuscular injection may be preferred because muscles have l ...
(
injection Injection or injected may refer to: Science and technology * Injective function, a mathematical function mapping distinct arguments to distinct values * Injection (medicine), insertion of liquid into the body with a syringe * Injection, in broadca ...
), and subcutaneous (
implant Implant can refer to: Medicine *Implant (medicine), or specifically: ** Brain implant ** Breast implant **Buttock implant **Cochlear implant **Contraceptive implant **Dental implant ** Fetal tissue implant **Implantable cardioverter-defibrillator ...
administration Administration may refer to: Management of organizations * Management, the act of directing people towards accomplishing a goal ** Administrative assistant, Administrative Assistant, traditionally known as a Secretary, or also known as an admini ...
. It is provided unmodified and as a testosterone ester such as testosterone cypionate,
testosterone enanthate Testosterone enanthate, sold under the brand names Delatestryl and Xyosted among others, is an androgen and anabolic steroid (AAS) medication which is used mainly in the treatment of low testosterone levels in men. It is also used in hormone th ...
, testosterone propionate, or testosterone undecanoate, which act as
prodrug A prodrug is a medication or compound that, after intake, is metabolized (i.e., converted within the body) into a pharmacologically active drug. Instead of administering a drug directly, a corresponding prodrug can be used to improve how the drug ...
s of testosterone. The most common
route of administration A route of administration in pharmacology and toxicology is the way by which a medication, drug, fluid, poison, or other substance is taken into the body. Routes of administration are generally classified by the location at which the substance i ...
for testosterone is by intramuscular injection. However, it has been reported that AndroGel, a transdermal gel formulation of testosterone, has become the most popular form of testosterone in androgen replacement therapy for hypogonadism in the United States.


Non-medical use


Athletics

Testosterone is used as a form of doping among
athlete An athlete (also sportsman or sportswoman) is a person who competes in one or more sports that involve physical strength, speed, or endurance. Athletes may be professionals or amateurs. Most professional athletes have particularly well-devel ...
s in order to improve performance. Testosterone is classified as an
anabolic Anabolism () is the set of metabolic pathways that construct molecules from smaller units. These reactions require energy, known also as an endergonic process. Anabolism is the building-up aspect of metabolism, whereas catabolism is the breaking-do ...
agent and is on the World Anti-Doping Agency (WADA) List of Prohibited Substances and Methods. Hormone supplements cause the endocrine system to adjust its production and lower the natural production of the hormone, so when supplements are discontinued, natural hormone production is lower than it was originally.
Anabolic–androgenic steroid Anabolic steroids, also known more properly as anabolic–androgenic steroids (AAS), are steroidal androgens that include natural androgens like testosterone as well as synthetic androgens that are structurally related and have similar effects t ...
s (AAS), including testosterone and its esters, have also been taken to enhance muscle development, strength, or endurance. They do so directly by increasing the muscles' protein synthesis. As a result, muscle fibers become larger and repair faster than the average person's. After a series of scandals and publicity in the 1980s (such as Ben Johnson's improved performance at the
1988 Summer Olympics The 1988 Summer Olympics (), officially known as the Games of the XXIV Olympiad () and commonly known as Seoul 1988 ( ko, 서울 1988, Seoul Cheon gubaek palsip-pal), was an international multi-sport event held from 17 September to 2 October ...
),
prohibition Prohibition is the act or practice of forbidding something by law; more particularly the term refers to the banning of the manufacture, storage (whether in barrels or in bottles), transportation, sale, possession, and consumption of alcoholic ...
s of AAS use were renewed or strengthened by many sports organizations. Testosterone and other AAS were designated a " controlled substance" by the
United States Congress The United States Congress is the legislature of the federal government of the United States. It is bicameral, composed of a lower body, the House of Representatives, and an upper body, the Senate. It meets in the U.S. Capitol in Washing ...
in 1990, with the ''Anabolic Steroid Control Act''. Their use is seen as an issue in modern sport, particularly given the lengths to which athletes and professional laboratories go to in trying to conceal such use from sports regulators. Steroid use once again came into the spotlight as a result of Canadian
professional wrestler Professional wrestling is a form of theater that revolves around staged wrestling matches. The mock combat is performed in a ring similar to the kind used in boxing, and the dramatic aspects of pro wrestling may be performed both in the ring or ...
Chris Benoit Christopher Michael Benoit (; May 21, 1967 – June 24, 2007) was a Canadian Professional wrestling, professional wrestler. He worked for various pro-wrestling promotions during his 22-year career including most notably the WWE, World Wrestlin ...
's double murder-suicide in 2007; however, there is no evidence implicating steroid use as a factor in the incident. Some female athletes may have naturally higher levels of testosterone than others, and may be asked to consent to sex verification and either surgery or drugs to decrease testosterone levels. This has proven contentious, with the
Court of Arbitration for Sport The Court of Arbitration for Sport (CAS; french: Tribunal arbitral du sport, ''TAS'') is an international body established in 1984 to settle disputes related to sport through arbitration. Its headquarters are in Lausanne, Switzerland and its co ...
suspending the IAAF policy due to insufficient evidence of a link between high androgen levels and improved athletic performance.


Detection of abuse

A number of methods for detecting testosterone use by athletes have been employed, most based on a urine test. These include the testosterone/
epitestosterone Epitestosterone, or isotestosterone, also known as 17α-testosterone or as androst-4-en-17α-ol-3-one, is an endogenous steroid and an epimer of the androgen sex hormone testosterone. It is a weak competitive antagonist of the androgen receptor (A ...
ratio (normally less than 6), the testosterone/luteinizing hormone ratio and the carbon-13/
carbon-12 Carbon-12 (12C) is the most abundant of the two stable isotopes of carbon (carbon-13 being the other), amounting to 98.93% of element carbon on Earth; its abundance is due to the triple-alpha process by which it is created in stars. Carbon-12 i ...
ratio (pharmaceutical testosterone contains less carbon-13 than endogenous testosterone). In some testing programs, an individual's own historical results may serve as a reference interval for interpretation of a suspicious finding. Another approach being investigated is the detection of the administered form of testosterone, usually an ester, in hair.


Contraindications

Absolute contraindications of testosterone include
prostate cancer Prostate cancer is cancer of the prostate. Prostate cancer is the second most common cancerous tumor worldwide and is the fifth leading cause of cancer-related mortality among men. The prostate is a gland in the male reproductive system that sur ...
, elevated hematocrit (>54%), uncontrolled
congestive heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, a ...
, various other
cardiovascular disease Cardiovascular disease (CVD) is a class of diseases that involve the heart or blood vessels. CVD includes coronary artery diseases (CAD) such as angina and myocardial infarction (commonly known as a heart attack). Other CVDs include stroke, h ...
s, and uncontrolled
obstructive sleep apnea Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder and is characterized by recurrent episodes of complete or partial obstruction of the upper airway leading to reduced or absent breathing during sleep. These episod ...
.
Breast cancer Breast cancer is cancer that develops from breast tissue. Signs of breast cancer may include a lump in the breast, a change in breast shape, dimpling of the skin, milk rejection, fluid coming from the nipple, a newly inverted nipple, or a re ...
is said by some sources to be an absolute contraindication of testosterone therapy, but androgens including testosterone have also actually been used to treat breast cancer. Relative contraindications of testosterone include elevated
prostate-specific antigen Prostate-specific antigen (PSA), also known as gamma-seminoprotein or kallikrein-3 (KLK3), P-30 antigen, is a glycoprotein enzyme encoded in humans by the ''KLK3'' gene. PSA is a member of the kallikrein-related peptidase family and is secreted b ...
(PSA) in men with a high risk of prostate cancer due to
ethnicity An ethnic group or an ethnicity is a grouping of people who identify with each other on the basis of shared attributes that distinguish them from other groups. Those attributes can include common sets of traditions, ancestry, language, history, ...
or family history, severe lower urinary tract symptoms, and elevated hematocrit (>50%).


Side effects

Adverse effects may also include minor side effects such as oily skin, acne, and seborrhea, as well as loss of scalp hair, which may be prevented or reduced with
5α-reductase inhibitors 5α-Reductases, also known as 3-oxo-5α-steroid 4-dehydrogenases, are enzymes involved in steroid metabolism. They participate in three metabolic pathways: bile acid biosynthesis, androgen and estrogen metabolism. There are three isozymes of ...
. In women, testosterone can produce hirsutism (excessive facial/body hair growth), deepening of the voice, and other signs of virilization. Exogenous testosterone may cause suppression of
spermatogenesis Spermatogenesis is the process by which haploid spermatozoa develop from germ cells in the seminiferous tubules of the testis. This process starts with the mitotic division of the stem cells located close to the basement membrane of the tubule ...
in men, leading to, in some cases, reversible
infertility Infertility is the inability of a person, animal or plant to reproduce by natural means. It is usually not the natural state of a healthy adult, except notably among certain eusocial species (mostly haplodiploid insects). It is the normal state ...
. Gynecomastia and breast tenderness may occur with high dosages of testosterone due to peripheral conversion of testosterone by aromatase into excessive amounts of the
estrogen Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal acti ...
estradiol. Testosterone treatment, particularly in high dosages, can also be associated with
mood changes A mood swing is an extreme or sudden change of mood. Such changes can play a positive part in promoting problem solving and in producing flexible forward planning, or be disruptive. When mood swings are severe, they may be categorized as par ...
, increased
aggression Aggression is overt or covert, often harmful, social interaction with the intention of inflicting damage or other harm upon another individual; although it can be channeled into creative and practical outlets for some. It may occur either reacti ...
, increased
sex drive Libido (; colloquial: sex drive) is a person's overall sexual drive or desire for sexual activity. Libido is influenced by biological, psychological, and social factors. Biologically, the sex hormones and associated neurotransmitters that act upo ...
,
spontaneous erection An erection (clinically: penile erection or penile tumescence) is a physiological phenomenon in which the penis becomes firm, engorged, and enlarged. Penile erection is the result of a complex interaction of psychological, neural, vascular, a ...
s, and nocturnal emissions. Other side effects include increased hematocrit, which can require venipuncture in order to treat, and exacerbation of sleep apnea. The FDA stated in 2015 that neither the benefits nor the safety of testosterone have been established for low testosterone levels due to aging. The FDA has required that testosterone pharmaceutical labels include warning information about the possibility of an increased risk of heart attacks and stroke. They have also required the label include concerns about abuse and dependence. Injectable forms of testosterone can cause a lung problem called pulmonary oil microembolism (POME). Symptoms of POME include cough, shortness of breath, tightening of the throat, chest pain, sweating, dizziness, and fainting. A postmarketing analysis by the manufacturer of Aveed (testosterone undeconate injection) found that POME occurred at a rate of less than 1% per injection per year for Aveed.


Long-term adverse effects


Cardiovascular disease

Adverse effects of testosterone supplementation may include increased cardiovascular events (including
stroke A stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop functionin ...
s and
heart attack A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which may tr ...
s) and
death Death is the irreversible cessation of all biological functions that sustain an organism. For organisms with a brain, death can also be defined as the irreversible cessation of functioning of the whole brain, including brainstem, and brain ...
s based on three peer-reviewed studies involving men taking testosterone replacement. In addition, an increase of 30% in deaths and heart attacks in older men has been reported. Due to an increased incidence of adverse cardiovascular events compared to a
placebo group Clinical trials are prospective biomedical or behavioral research studies on human participants designed to answer specific questions about biomedical or behavioral interventions, including new treatments (such as novel vaccines, drugs, dieta ...
, a Testosterone in Older Men with Mobility Limitations (TOM) trial (a
National Institute of Aging The National Institute on Aging (NIA) is a division of the U.S. National Institutes of Health (NIH), located in Bethesda, Maryland. The NIA itself is headquartered in Baltimore, Maryland. The NIA leads a broad scientific effort to understand the ...
randomized trial) was halted early by the Data Safety and Monitoring Committee. On January 31, 2014, reports of
stroke A stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop functionin ...
s,
heart attack A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which may tr ...
s, and
death Death is the irreversible cessation of all biological functions that sustain an organism. For organisms with a brain, death can also be defined as the irreversible cessation of functioning of the whole brain, including brainstem, and brain ...
s in men taking FDA-approved testosterone-replacement led the FDA to announce that it would be investigating the issue. Later, in September 2014, the FDA announced, as a result of the "potential for adverse cardiovascular outcomes", a review of the appropriateness and safety of Testosterone Replacement Therapy (TRT). The FDA now requires warnings in the drug labeling of all approved testosterone products regarding deep vein thrombosis and pulmonary embolism. Up to the year 2010, studies had not shown any effect on the risk of death,
prostate cancer Prostate cancer is cancer of the prostate. Prostate cancer is the second most common cancerous tumor worldwide and is the fifth leading cause of cancer-related mortality among men. The prostate is a gland in the male reproductive system that sur ...
or
cardiovascular disease Cardiovascular disease (CVD) is a class of diseases that involve the heart or blood vessels. CVD includes coronary artery diseases (CAD) such as angina and myocardial infarction (commonly known as a heart attack). Other CVDs include stroke, h ...
; more recent studies, however, do raise concerns. A 2013 study, published in the Journal of the American Medical Association, reported "the use of testosterone therapy was significantly associated with increased risk of adverse outcomes." The study began after a previous, randomized, clinical trial of testosterone therapy in men was stopped prematurely "due to adverse cardiovascular events raising concerns about testosterone therapy safety."


Prostate cancer

Testosterone in the presence of a slow-growing prostate cancer is assumed to increase its growth rate. However, the association between testosterone supplementation and the development of prostate cancer is unproven. Nevertheless, physicians are cautioned about the cancer risk associated with testosterone supplementation. Testosterone may accelerate pre-existing
prostate cancer Prostate cancer is cancer of the prostate. Prostate cancer is the second most common cancerous tumor worldwide and is the fifth leading cause of cancer-related mortality among men. The prostate is a gland in the male reproductive system that sur ...
growth in individuals who have undergone androgen deprivation. It is recommended that physicians screen for prostate cancer with a digital rectal exam and
prostate-specific antigen Prostate-specific antigen (PSA), also known as gamma-seminoprotein or kallikrein-3 (KLK3), P-30 antigen, is a glycoprotein enzyme encoded in humans by the ''KLK3'' gene. PSA is a member of the kallikrein-related peptidase family and is secreted b ...
(PSA) level before starting therapy, and monitor PSA and hematocrit levels closely during therapy. Ethnic groups have different rates of prostate cancer. Differences in sex hormones, including testosterone, have been suggested as an explanation for these differences. This apparent paradox can be resolved by noting that prostate cancer is very common. In autopsies, 80% of 80-year-old men have prostate cancer.


Pregnancy and breastfeeding

Testosterone is contraindicated in
pregnancy Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occurs by sexual intercourse, but ca ...
and not recommended during
breastfeeding Breastfeeding, or nursing, is the process by which human breast milk is fed to a child. Breast milk may be from the breast, or may be expressed by hand or pumped and fed to the infant. The World Health Organization (WHO) recommends that br ...
. Androgens like testosterone are teratogens and are known to cause fetal harm, such as producing virilization and
ambiguous genitalia Intersex people are individuals born with any of several sex characteristics including chromosome patterns, gonads, or genitals that, according to the Office of the United Nations High Commissioner for Human Rights, "do not fit typical bina ...
.


Interactions


5α-Reductase inhibitors

5α-Reductase inhibitor 5α-Reductases, also known as 3-oxo-5α-steroid 4-dehydrogenases, are enzymes involved in steroid metabolism. They participate in three metabolic pathways: bile acid biosynthesis, androgen and estrogen metabolism. There are three isozymes of ...
s like
finasteride Finasteride, sold under the brand names Proscar and Propecia among others, is a medication used to treat hair loss and benign prostatic hyperplasia (BPH) in men. It can also be used to treat excessive hair growth in women and as a part of horm ...
and dutasteride can slightly increase circulating levels of testosterone by inhibiting its
metabolism Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...
. However, these drugs do this via prevention of the conversion of testosterone into its more potent
metabolite In biochemistry, a metabolite is an intermediate or end product of metabolism. The term is usually used for small molecules. Metabolites have various functions, including fuel, structure, signaling, stimulatory and inhibitory effects on enzymes, c ...
dihydrotestosterone Dihydrotestosterone (DHT, 5α-dihydrotestosterone, 5α-DHT, androstanolone or stanolone) is an endogenous androgen sex steroid and hormone. The enzyme 5α-reductase catalyzes the formation of DHT from testosterone in certain tissues includi ...
(DHT), and this results in dramatically reduced circulating levels of DHT (which circulates at much lower relative concentrations). In addition, local levels of DHT in so-called androgenic (5α-reductase-expressing) tissues are also markedly reduced, and this can have a strong impact on certain effects of testosterone. For instance, growth of body and facial hair and
penile growth The human penis is an external male intromittent organ that additionally serves as the urinary duct. The main parts are the root (radix); the body (corpus); and the epithelium of the penis including the shaft skin and the foreskin (prepuce) co ...
induced by testosterone may be inhibited by 5α-reductase inhibitors, and this could be considered undesirable in the context of, for instance,
puberty induction Delayed puberty is when a person lacks or has incomplete development of specific sexual characteristics past the usual age of onset of puberty. The person may have no physical or hormonal signs that puberty has begun. In the United States, girls ar ...
. On the other hand, 5α-reductase inhibitors may prevent or reduce adverse androgenic side effects of testosterone like
scalp hair loss Pattern hair loss (also known as androgenetic alopecia (AGA)) is a hair loss condition that primarily affects the top and front of the scalp. In male-pattern hair loss (MPHL), the hair loss typically presents itself as either a receding front ha ...
,
oily skin The human skin is the outer covering of the body and is the largest organ of the integumentary system. The skin has up to seven layers of ectodermal tissue guarding muscles, bones, ligaments and internal organs. Human skin is similar to most ...
,
acne Acne, also known as ''acne vulgaris'', is a long-term Cutaneous condition, skin condition that occurs when Keratinocyte, dead skin cells and Sebum, oil from the skin clog hair follicles. Typical features of the condition include comedo, black ...
, and
seborrhea A sebaceous gland is a microscopic exocrine gland in the skin that opens into a hair follicle to secrete an oily or waxy matter, called sebum, which lubricates the hair and skin of mammals. In humans, sebaceous glands occur in the greatest numbe ...
. In addition to the prevention of testosterone conversion into DHT, 5α-reductase inhibitors also prevent the formation of
neurosteroid Neurosteroids, also known as neuroactive steroids, are endogenous or exogenous steroids that rapidly alter neuronal excitability through interaction with ligand-gated ion channels and other cell surface receptors. The term ''neurosteroid'' was coin ...
s like 3α-androstanediol from testosterone, and this may have neuropsychiatric consequences in some men.


Aromatase inhibitors

Aromatase inhibitors like anastrozole prevent the conversion of testosterone into estradiol by aromatase. As only a very small fraction of testosterone is converted into estradiol, this does not affect testosterone levels, but it can prevent
estrogen Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal acti ...
ic side effects like gynecomastia that can occur when testosterone is administered at relatively high dosages. However, estradiol exerts
negative feedback Negative feedback (or balancing feedback) occurs when some function (Mathematics), function of the output of a system, process, or mechanism is feedback, fed back in a manner that tends to reduce the fluctuations in the output, whether caused by ...
on the hypothalamic–pituitary–gonadal axis and, for this reason, prevention of its formation can reduce this feedback and disinhibit gonadal production of testosterone, which in turn can increase levels of endogenous testosterone. Testosterone therapy is sometimes combined with an aromatase inhibitor for men with secondary hypogonadism who wish to conceive children with their partners.


Cytochrome P450 inhibitors

Inhibitor Inhibitor or inhibition may refer to: In biology * Enzyme inhibitor, a substance that binds to an enzyme and decreases the enzyme's activity * Reuptake inhibitor, a substance that increases neurotransmission by blocking the reuptake of a neurotra ...
s and
inducer In molecular biology, an inducer is a molecule that regulates gene expression. An inducer functions in two ways; namely: *By disabling repressors. The gene is expressed because an inducer binds to the repressor. The binding of the inducer to the r ...
s of
cytochrome P450 Cytochromes P450 (CYPs) are a Protein superfamily, superfamily of enzymes containing heme as a cofactor (biochemistry), cofactor that functions as monooxygenases. In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are ...
enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
s like
CYP3A4 Cytochrome P450 3A4 (abbreviated CYP3A4) () is an important enzyme in the body, mainly found in the liver and in the intestine. It oxidizes small foreign organic molecules (xenobiotics), such as toxins or drugs, so that they can be removed from t ...
have been associated with little or no effect on circulating testosterone levels.


Antiandrogens and estrogens

Antiandrogens like cyproterone acetate,
spironolactone Spironolactone, sold under the brand name Aldactone among others, is a medication that is primarily used to treat fluid build-up due to heart failure, liver scarring, or kidney disease. It is also used in the treatment of high blood pressure ...
, and bicalutamide can block the androgenic and anabolic effects of testosterone.
Estrogen Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal acti ...
s can reduce the effects of testosterone by increasing the hepatic production and in turn circulating levels of sex hormone-binding globulin (SHBG), a carrier protein that binds to and occupies androgens like testosterone and DHT, and thereby reducing free concentrations of these androgens.


Pharmacology


Pharmacodynamics

Testosterone is a high
affinity Affinity may refer to: Commerce, finance and law * Affinity (law), kinship by marriage * Affinity analysis, a market research and business management technique * Affinity Credit Union, a Saskatchewan-based credit union * Affinity Equity Partn ...
ligand In coordination chemistry, a ligand is an ion or molecule (functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electr ...
for and
agonist An agonist is a chemical that activates a receptor to produce a biological response. Receptors are cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an antagonist blocks the action of the ago ...
of the
nuclear Nuclear may refer to: Physics Relating to the nucleus of the atom: * Nuclear engineering *Nuclear physics *Nuclear power *Nuclear reactor *Nuclear weapon *Nuclear medicine *Radiation therapy *Nuclear warfare Mathematics *Nuclear space *Nuclear ...
androgen receptor The androgen receptor (AR), also known as NR3C4 (nuclear receptor subfamily 3, group C, member 4), is a type of nuclear receptor that is activated by binding any of the androgenic hormones, including testosterone and dihydrotestosterone in th ...
(AR). In addition, testosterone binds to and activates
membrane androgen receptor Membrane androgen receptors (mARs) are a group of G protein-coupled receptors (GPCRs) which bind and are activated by testosterone and/or other androgens. Unlike the androgen receptor (AR), a nuclear receptor which mediates its effects via genomi ...
s (mARs) such as GPRC6A and
ZIP9 Zinc transporter ZIP9, also known as Zrt- and Irt-like protein 9 (ZIP9) and solute carrier family 39 member 9, is a protein that in humans is encoded by the ''SLC39A9'' gene. This protein is the 9th member out of 14 ZIP family proteins, which is ...
. Testosterone is also potentiated via
transformation Transformation may refer to: Science and mathematics In biology and medicine * Metamorphosis, the biological process of changing physical form after birth or hatching * Malignant transformation, the process of cells becoming cancerous * Trans ...
by
5α-reductase 5α-Reductases, also known as 3-oxo-5α-steroid 4-dehydrogenases, are enzymes involved in steroid metabolism. They participate in three metabolic pathways: bile acid biosynthesis, androgen and estrogen metabolism. There are three isozymes of ...
into the more potent androgen DHT in so-called androgenic tissues such as the
prostate gland The prostate is both an accessory gland of the male reproductive system and a muscle-driven mechanical switch between urination and ejaculation. It is found only in some mammals. It differs between species anatomically, chemically, and physio ...
, seminal vesicles,
skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other cuticle, animal coverings, such as the arthropod exoskeleton, have diffe ...
, and
hair follicle The hair follicle is an organ found in mammalian skin. It resides in the dermal layer of the skin and is made up of 20 different cell types, each with distinct functions. The hair follicle regulates hair growth via a complex interaction between h ...
s. In contrast to the case of testosterone, such potentiation occurs to a reduced extent or not at all with most
synthetic Synthetic things are composed of multiple parts, often with the implication that they are artificial. In particular, 'synthetic' may refer to: Science * Synthetic chemical or compound, produced by the process of chemical synthesis * Synthetic o ...
AAS (as well as with DHT), and this is primarily responsible for the dissociation of
anabolic Anabolism () is the set of metabolic pathways that construct molecules from smaller units. These reactions require energy, known also as an endergonic process. Anabolism is the building-up aspect of metabolism, whereas catabolism is the breaking-do ...
and androgenic effects with these agents. In addition to DHT, testosterone is converted at a rate of approximately 0.3% into the
estrogen Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal acti ...
estradiol via aromatase. This occurs in many tissues, especially adipose tissue, the
liver The liver is a major Organ (anatomy), organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of proteins and biochemicals necessary for ...
, and the
brain A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a v ...
, but primarily in adipose tissue. Testosterone, after conversion into DHT, is also metabolized into 3α-androstanediol, a
neurosteroid Neurosteroids, also known as neuroactive steroids, are endogenous or exogenous steroids that rapidly alter neuronal excitability through interaction with ligand-gated ion channels and other cell surface receptors. The term ''neurosteroid'' was coin ...
and potent
positive allosteric modulator In pharmacology and biochemistry, allosteric modulators are a group of substances that bind to a receptor to change that receptor's response to stimulus. Some of them, like benzodiazepines, are drugs. The site that an allosteric modulator binds to ...
of the GABAA receptor, and
3β-androstanediol 3β-Androstanediol, also known as 5α-androstane-3β,17β-diol, and sometimes shortened in the literature to 3β-diol, is an endogenous steroid hormone and a metabolite of androgens like dehydroepiandrosterone (DHEA) and dihydrotestosterone (DHT). ...
, a potent and preferential agonist of the
ERβ Estrogen receptor beta (ERβ) also known as NR3A2 (nuclear receptor subfamily 3, group A, member 2) is one of two main types of estrogen receptor—a nuclear receptor which is activated by the sex hormone estrogen. In humans ERβ is encoded by ...
. These metabolites, along with estradiol, may be involved in a number of the effects of testosterone in the brain, including its
antidepressant Antidepressants are a class of medication used to treat major depressive disorder, anxiety disorders, chronic pain conditions, and to help manage addictions. Common side-effects of antidepressants include dry mouth, weight gain, dizziness, hea ...
, anxiolytic, stress-relieving,
rewarding The reward system (the mesocorticolimbic circuit) is a group of neural structures responsible for incentive salience (i.e., "wanting"; desire or craving for a reward and motivation), associative learning (primarily positive reinforcement and class ...
, and pro-sexual effects.


Effects in the body and brain

The ARs are expressed widely throughout the body, including in the
penis A penis (plural ''penises'' or ''penes'' () is the primary sexual organ that male animals use to inseminate females (or hermaphrodites) during copulation. Such organs occur in many animals, both vertebrate and invertebrate, but males do n ...
,
testicle A testicle or testis (plural testes) is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testostero ...
s,
epididymides The epididymis (; plural: epididymides or ) is a tube that connects a testicle to a vas deferens in the male reproductive system. It is a single, narrow, tightly-coiled tube in adult humans, in length. It serves as an interconnection between the ...
,
prostate gland The prostate is both an accessory gland of the male reproductive system and a muscle-driven mechanical switch between urination and ejaculation. It is found only in some mammals. It differs between species anatomically, chemically, and physio ...
, seminal vesicles,
fat In nutrition science, nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such chemical compound, compounds, most commonly those that occur in living beings or in food. The term often refers spec ...
,
skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other cuticle, animal coverings, such as the arthropod exoskeleton, have diffe ...
,
bone A bone is a Stiffness, rigid Organ (biology), organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red blood cell, red and white blood cells, store minerals, provid ...
,
bone marrow Bone marrow is a semi-solid tissue found within the spongy (also known as cancellous) portions of bones. In birds and mammals, bone marrow is the primary site of new blood cell production (or haematopoiesis). It is composed of hematopoietic ce ...
,
muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...
,
larynx The larynx (), commonly called the voice box, is an organ in the top of the neck involved in breathing, producing sound and protecting the trachea against food aspiration. The opening of larynx into pharynx known as the laryngeal inlet is about ...
,
heart The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide t ...
,
liver The liver is a major Organ (anatomy), organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of proteins and biochemicals necessary for ...
,
kidney The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blood ...
s,
pituitary gland In vertebrate anatomy, the pituitary gland, or hypophysis, is an endocrine gland, about the size of a chickpea and weighing, on average, in humans. It is a protrusion off the bottom of the hypothalamus at the base of the brain. The ...
,
hypothalamus The hypothalamus () is a part of the brain that contains a number of small nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrine system via the pituitary gland. The hypothalamu ...
, and elsewhere throughout the
brain A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a v ...
. Through activation of the ARs (as well as the mARs), testosterone has many effects, including the following: * Promotes growth, function, and maintenance of the
prostate gland The prostate is both an accessory gland of the male reproductive system and a muscle-driven mechanical switch between urination and ejaculation. It is found only in some mammals. It differs between species anatomically, chemically, and physio ...
, seminal vesicles, and
penis A penis (plural ''penises'' or ''penes'' () is the primary sexual organ that male animals use to inseminate females (or hermaphrodites) during copulation. Such organs occur in many animals, both vertebrate and invertebrate, but males do n ...
during
puberty Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. It is initiated by hormonal signals from the brain to the gonads: the ovaries in a girl, the testes in a boy. ...
and thereafter * Promotes growth and maintenance of
muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...
s, particularly of the
upper body The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the crea ...
* Causes subcutaneous fat to be deposited in a masculine pattern and decreases overall body fat * Suppresses breast development induced by
estrogen Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal acti ...
s, but can also still produce gynecomastia via excessive conversion into estradiol if levels are too high * Maintains skin health, integrity, appearance, and hydration and slows the rate of aging of the skin, but can also cause
oily skin The human skin is the outer covering of the body and is the largest organ of the integumentary system. The skin has up to seven layers of ectodermal tissue guarding muscles, bones, ligaments and internal organs. Human skin is similar to most ...
,
acne Acne, also known as ''acne vulgaris'', is a long-term Cutaneous condition, skin condition that occurs when Keratinocyte, dead skin cells and Sebum, oil from the skin clog hair follicles. Typical features of the condition include comedo, black ...
, and
seborrhea A sebaceous gland is a microscopic exocrine gland in the skin that opens into a hair follicle to secrete an oily or waxy matter, called sebum, which lubricates the hair and skin of mammals. In humans, sebaceous glands occur in the greatest numbe ...
* Promotes the growth of facial and
body hair Body hair, or androgenic hair, is the terminal hair that develops on the human body during and after puberty. It is differentiated from the head hair and less visible vellus hair, which is much finer and lighter in color. The growth of androge ...
, but can also cause
scalp hair loss Pattern hair loss (also known as androgenetic alopecia (AGA)) is a hair loss condition that primarily affects the top and front of the scalp. In male-pattern hair loss (MPHL), the hair loss typically presents itself as either a receding front ha ...
and hirsutism * Contributes to bone growth and causes
broadening of the shoulders The human shoulder is made up of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone) as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder mak ...
at puberty * Modulates liver protein synthesis, such as the production of sex hormone-binding globulin and many other proteins * Increases production of
erythropoietin Erythropoietin (; EPO), also known as erythropoetin, haematopoietin, or haemopoietin, is a glycoprotein cytokine secreted mainly by the kidneys in response to cellular hypoxia; it stimulates red blood cell production (erythropoiesis) in the bo ...
in the
kidney The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blood ...
s and thereby stimulates
red blood cell Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "holl ...
production in bone marrow and elevates hematocrit * Exerts
negative feedback Negative feedback (or balancing feedback) occurs when some function (Mathematics), function of the output of a system, process, or mechanism is feedback, fed back in a manner that tends to reduce the fluctuations in the output, whether caused by ...
on the hypothalamic–pituitary–gonadal axis by suppressing the
secretion 440px Secretion is the movement of material from one point to another, such as a secreted chemical substance from a cell or gland. In contrast, excretion is the removal of certain substances or waste products from a cell or organism. The classical ...
of the gonadotropins
follicle-stimulating hormone Follicle-stimulating hormone (FSH) is a gonadotropin, a glycoprotein polypeptide hormone. FSH is synthesized and secreted by the gonadotropic cells of the anterior pituitary gland and regulates the development, growth, pubertal maturation, an ...
(FSH) and luteinizing hormone (LH) from the
pituitary gland In vertebrate anatomy, the pituitary gland, or hypophysis, is an endocrine gland, about the size of a chickpea and weighing, on average, in humans. It is a protrusion off the bottom of the hypothalamus at the base of the brain. The ...
, thereby inhibiting
gonad A gonad, sex gland, or reproductive gland is a mixed gland that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gonad, the testicle, produces sper ...
al
sex hormone Sex hormones, also known as sex steroids, gonadocorticoids and gonadal steroids, are steroid hormones that interact with vertebrate steroid hormone receptors. The sex hormones include the androgens, estrogens, and progestogens. Their effects ar ...
production Production may refer to: Economics and business * Production (economics) * Production, the act of manufacturing goods * Production, in the outline of industrial organization, the act of making products (goods and services) * Production as a stati ...
as well as
spermatogenesis Spermatogenesis is the process by which haploid spermatozoa develop from germ cells in the seminiferous tubules of the testis. This process starts with the mitotic division of the stem cells located close to the basement membrane of the tubule ...
and
fertility Fertility is the capability to produce offspring through reproduction following the onset of sexual maturity. The fertility rate is the average number of children born by a female during her lifetime and is quantified demographically. Fertili ...
* Regulates the
vasomotor system Vasodilation is the widening of blood vessels. It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. The process is the opposite of vasoconstriction, ...
and
body temperature Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature ...
via the
hypothalamus The hypothalamus () is a part of the brain that contains a number of small nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrine system via the pituitary gland. The hypothalamu ...
, thereby preventing
hot flash Hot flashes (also known as hot flushes) are a form of flushing, often caused by the changing hormone levels that are characteristic of menopause. They are typically experienced as a feeling of intense heat with sweating and rapid heartbeat, and ...
es * Modulates brain function, with effects on mood, emotionality,
aggression Aggression is overt or covert, often harmful, social interaction with the intention of inflicting damage or other harm upon another individual; although it can be channeled into creative and practical outlets for some. It may occur either reacti ...
, and
sexuality Human sexuality is the way people experience and express themselves sexually. This involves biological, psychological, physical, erotic, emotional, social, or spiritual feelings and behaviors. Because it is a broad term, which has varied ...
, as well as
cognition Cognition refers to "the mental action or process of acquiring knowledge and understanding through thought, experience, and the senses". It encompasses all aspects of intellectual functions and processes such as: perception, attention, thought, ...
and
memory Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembered, ...
* Increases
sex drive Libido (; colloquial: sex drive) is a person's overall sexual drive or desire for sexual activity. Libido is influenced by biological, psychological, and social factors. Biologically, the sex hormones and associated neurotransmitters that act upo ...
and erectile capacity and causes
spontaneous erection An erection (clinically: penile erection or penile tumescence) is a physiological phenomenon in which the penis becomes firm, engorged, and enlarged. Penile erection is the result of a complex interaction of psychological, neural, vascular, a ...
s and nocturnal emissions * Increases the risk of benign prostatic hyperplasia and
prostate cancer Prostate cancer is cancer of the prostate. Prostate cancer is the second most common cancerous tumor worldwide and is the fifth leading cause of cancer-related mortality among men. The prostate is a gland in the male reproductive system that sur ...
and accelerates the progression of prostate cancer * Decreases
breast proliferation Breast development, also known as mammogenesis, is a complex biological process in primates that takes place throughout a female's life. It occurs across several phases, including prenatal development, puberty, and pregnancy. At menopause, bre ...
and the risk of
breast cancer Breast cancer is cancer that develops from breast tissue. Signs of breast cancer may include a lump in the breast, a change in breast shape, dimpling of the skin, milk rejection, fluid coming from the nipple, a newly inverted nipple, or a re ...


Pharmacokinetics

Testosterone can be taken by a variety of different routes of administration. These include
oral The word oral may refer to: Relating to the mouth * Relating to the mouth, the first portion of the alimentary canal that primarily receives food and liquid **Oral administration of medicines ** Oral examination (also known as an oral exam or oral ...
, buccal,
sublingual Sublingual (abbreviated SL), from the Latin for "under the tongue", refers to the pharmacological route of administration by which substances diffuse into the blood through tissues under the tongue. The sublingual glands receive their prima ...
,
intranasal Nasal administration, popularly known as snorting, is a route of administration in which drugs are insufflated through the nose. It can be a form of either topical administration or systemic administration, as the drugs thus locally delivered ...
, transdermal (
gel A gel is a semi-solid that can have properties ranging from soft and weak to hard and tough. Gels are defined as a substantially dilute cross-linked system, which exhibits no flow when in the steady-state, although the liquid phase may still di ...
s,
cream Cream is a dairy product composed of the higher-fat layer skimmed from the top of milk before homogenization. In un-homogenized milk, the fat, which is less dense, eventually rises to the top. In the industrial production of cream, this process ...
s,
patch Patch or Patches may refer to: Arts, entertainment and media * Patch Johnson, a fictional character from ''Days of Our Lives'' * Patch (''My Little Pony''), a toy * "Patches" (Dickey Lee song), 1962 * "Patches" (Chairmen of the Board song) ...
es), rectal
suppositories A suppository is a dosage form used to deliver medications by insertion into a body orifice where it dissolves or melts to exert local or systemic effects. There are three types of suppositories, each to insert into a different sections: rectal su ...
), by
intramuscular Intramuscular injection, often abbreviated IM, is the injection of a substance into a muscle. In medicine, it is one of several methods for parenteral administration of medications. Intramuscular injection may be preferred because muscles have l ...
or subcutaneous
injection Injection or injected may refer to: Science and technology * Injective function, a mathematical function mapping distinct arguments to distinct values * Injection (medicine), insertion of liquid into the body with a syringe * Injection, in broadca ...
(in oil or aqueous), and as a
subcutaneous implant In medicine, a subcutaneous implant, or subcutaneous pellet, is an implant that is delivered under the skin into the subcutaneous tissue by surgery or injection and is used to deliver a drug for a long period of time. Examples of drugs that can ...
. The
pharmacokinetics Pharmacokinetics (from Ancient Greek ''pharmakon'' "drug" and ''kinetikos'' "moving, putting in motion"; see chemical kinetics), sometimes abbreviated as PK, is a branch of pharmacology dedicated to determining the fate of substances administered ...
of testosterone, including its bioavailability, circulating testosterone levels,
metabolism Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...
, biological half-life, and other parameters, differ by route of administration.


Chemistry

Testosterone is a naturally occurring androstane
steroid A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes that alter membrane fluidity; and a ...
and is also known by the chemical name androst-4-en-17β-ol-3-one. It has a double bond between the C4 and C5 positions (making it an
androstene Androstane is a C19 steroidal hydrocarbon with a gonane core. Androstane can exist as either of two isomers, known as 5α-androstane and 5β-androstane. File:androstane.png, 5α-Androstane File:androstane 5beta.png, 5β-Androstane Pharmacology ...
), a
ketone In organic chemistry, a ketone is a functional group with the structure R–C(=O)–R', where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group –C(=O)– (which contains a carbon-oxygen double bo ...
group at the C3 position, and a
hydroxyl In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy ...
(
alcohol Alcohol most commonly refers to: * Alcohol (chemistry), an organic compound in which a hydroxyl group is bound to a carbon atom * Alcohol (drug), an intoxicant found in alcoholic drinks Alcohol may also refer to: Chemicals * Ethanol, one of sev ...
) group at the C17β position.


Derivatives

Testosterone esters are
substituted A substitution reaction (also known as single displacement reaction or single substitution reaction) is a chemical reaction during which one functional group in a chemical compound is replaced by another functional group. Substitution reactions ar ...
at the C17β position with a lipophilic
fatty acid In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, fr ...
ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ar ...
moiety Moiety may refer to: Chemistry * Moiety (chemistry), a part or functional group of a molecule ** Moiety conservation, conservation of a subgroup in a chemical species Anthropology * Moiety (kinship), either of two groups into which a society is ...
of varying
chain A chain is a serial assembly of connected pieces, called links, typically made of metal, with an overall character similar to that of a rope in that it is flexible and curved in compression but linear, rigid, and load-bearing in tension. A c ...
length. Major testosterone esters include testosterone cypionate,
testosterone enanthate Testosterone enanthate, sold under the brand names Delatestryl and Xyosted among others, is an androgen and anabolic steroid (AAS) medication which is used mainly in the treatment of low testosterone levels in men. It is also used in hormone th ...
, testosterone propionate, and testosterone undecanoate. A C17β
ether In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again be c ...
prodrug A prodrug is a medication or compound that, after intake, is metabolized (i.e., converted within the body) into a pharmacologically active drug. Instead of administering a drug directly, a corresponding prodrug can be used to improve how the drug ...
of testosterone,
cloxotestosterone acetate Cloxotestosterone acetate (; brand name Caprosem), also known as testosterone 17β-chloral hemiacetal ''O''-acetate, is a synthetic, injected anabolic–androgenic steroid (AAS) and an androgen ether and ester – specifically, the ''O''- ace ...
, has also been marketed, although it is little known and is used very rarely or no longer. Another C17β ether prodrug of testosterone,
silandrone Silandrone (, ) (developmental code name SC-16148), also known as testosterone 17β-trimethylsilyl ether or 17β-trimethylsilyltestosterone, as well as 17β-(trimethylsiloxy)androst-4-en-3-one, is a synthetic anabolic-androgenic steroid (AAS) an ...
, also exists but was never marketed, and is notable in that it is orally active. In addition to ester and ether prodrugs,
androgen prohormone An androgen prohormone, or proandrogen, is a prohormone (or prodrug) of an anabolic-androgenic steroid (AAS). They can be prohormones of testosterone or of synthetic compound, synthetic AAS, for example, nandrolone (19-nortestosterone). Dehydroepia ...
s or
precursor Precursor or Precursors may refer to: *Precursor (religion), a forerunner, predecessor ** The Precursor, John the Baptist Science and technology * Precursor (bird), a hypothesized genus of fossil birds that was composed of fossilized parts of unr ...
s of testosterone, such as
dehydroepiandrosterone Dehydroepiandrosterone (DHEA), also known as androstenolone, is an endogenous steroid hormone precursor. It is one of the most abundant circulating steroids in humans. DHEA is produced in the adrenal glands, the gonads, and the brain. It functio ...
(DHEA),
androstenediol Androstenediol, or 5-androstenediol (abbreviated as A5 or Δ5-diol), also known as androst-5-ene-3β,17β-diol, is an endogenous weak androgen and estrogen steroid hormone and intermediate in the biosynthesis of testosterone from dehydroepiand ...
, and
androstenedione Androstenedione, or 4-androstenedione (abbreviated as A4 or Δ4-dione), also known as androst-4-ene-3,17-dione, is an endogenous weak androgen steroid hormone and intermediate in the biosynthesis of estrone and of testosterone from dehydroepia ...
, exist as well, and convert into testosterone to variable extents upon oral ingestion. Unlike testosterone ester and ether prodrugs however, these prohormones are only weakly androgenic/anabolic. All synthetic AAS are
derivative In mathematics, the derivative of a function of a real variable measures the sensitivity to change of the function value (output value) with respect to a change in its argument (input value). Derivatives are a fundamental tool of calculus. F ...
s of testosterone. Prominent examples include nandrolone (19-nortestosterone), metandienone (17α-methyl-δ1-testosterone), and stanozolol (a 17α-alkylated derivative of DHT). Unlike testosterone, AAS that are 17α-alkylated, like metandienone and stanozolol, are orally active. This is due to steric hindrance of C17β-position metabolism during the first-pass through the liver. In contrast, most AAS that are not 17α-alkylated, like nandrolone, are not active orally, and must instead be administered via intramuscular injection. This is almost always in ester form; for instance, in the case of nandrolone, as
nandrolone decanoate Nandrolone decanoate, sold under the brand name Deca-Durabolin among others, is an androgen and anabolic steroid (AAS) medication which is used primarily in the treatment of anemias and wasting syndromes, as well as osteoporosis in menopausal wo ...
or
nandrolone phenylpropionate Nandrolone phenylpropionate (NPP), or nandrolone phenpropionate, sold under the brand name Durabolin among others, is an androgen and anabolic steroid (AAS) medication which has been used primarily in the treatment of breast cancer and osteopor ...
.


History

Testosterone was first isolated and synthesized in 1935. Shortly thereafter, in 1937, testosterone first became commercially available as a
pharmaceutical drug A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy (pharmacotherapy) is an important part of the medical field and re ...
in the form of pellets and then in ester form for intramuscular injection as the relatively short-acting testosterone propionate.
Methyltestosterone Methyltestosterone, sold under the brand names Android, Metandren, and Testred among others, is an androgen and anabolic steroid (AAS) medication which is used in the treatment of low testosterone levels in men, delayed puberty in boys, at low ...
, one of the first synthetic AAS and orally active androgens, was introduced in 1935, but was associated with hepatotoxicity and eventually became largely medically obsolete. In the mid-1950s, the longer-acting testosterone esters
testosterone enanthate Testosterone enanthate, sold under the brand names Delatestryl and Xyosted among others, is an androgen and anabolic steroid (AAS) medication which is used mainly in the treatment of low testosterone levels in men. It is also used in hormone th ...
and testosterone cypionate were introduced. They largely superseded testosterone propionate and became the major testosterone esters used medically for over half a century. In the 1970s, testosterone undecanoate was introduced for oral use in Europe, although intramuscular testosterone undecanoate had already been in use in China for several years. Intramuscular testosterone undecanoate was not introduced in Europe and the United States until much later (in the early to mid 2000s and 2014, respectively). The history of testosterone as a medication has been reviewed.


Society and culture


Usage

In the US in the 2000s, companies and figures in the popular media have heavily marketed notions of "andropause" as something parallel to
menopause Menopause, also known as the climacteric, is the time in women's lives when menstrual periods stop permanently, and they are no longer able to bear children. Menopause usually occurs between the age of 47 and 54. Medical professionals often d ...
; these notions have been rejected by the medical community. Additionally, advertising from drug companies selling testosterone and human growth hormone, as well as
dietary supplement A dietary supplement is a manufactured product intended to supplement one's diet by taking a pill, capsule, tablet, powder, or liquid. A supplement can provide nutrients either extracted from food sources or that are synthetic in order ...
companies selling all kinds of "boosters" for aging men, have emphasized the "need" of middle-aged or ageing men for testosterone. There is a medical condition called
late-onset hypogonadism Late-onset hypogonadism (LOH) or testosterone deficiency syndrome (TDS) is a condition in older men characterized by measurably low testosterone levels and clinical symptoms mostly of a sexual nature, including decreased desire for sex, fewer spon ...
; according to Thomas Perls and David J. Handelsman, writing in a 2015 editorial in the ''
Journal of the American Geriatrics Society Journal of the American Geriatrics Society is a peer-reviewed journal of the American Geriatrics Society The American Geriatrics Society (AGS) is a non-profit professional society founded on June 11, 1942, for health care professionals practi ...
'', it appears that this condition is
overdiagnosed Overdiagnosis is the diagnosis of disease that will never cause symptoms or death during a patient's ordinarily expected lifetime and thus presents no practical threat regardless of being pathologic. Overdiagnosis is a side effect of screening fo ...
and overtreated. Perls and Handelsman note that in the US, "sales of testosterone increased from $324 million in 2002 to $2 billion in 2012, and the number of testosterone doses prescribed climbed from 100 million in 2007 to half a billion in 2012, not including the additional contributions from compounding pharmacies, Internet, and direct-to-patient clinic sales."


Generic names

''Testosterone'' is the generic name of testosterone in English and Italian and the , , , , and of the drug, while ''testostérone'' is its French name and the . It is also referred to in
Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
as ''testosteronum'', in Spanish and Portuguese as ''testosterona'', and in German, Dutch, and Russian and other Slavic languages as ''testosteron''. The
Cyrillic script The Cyrillic script ( ), Slavonic script or the Slavic script, is a writing system used for various languages across Eurasia. It is the designated national script in various Slavic languages, Slavic, Turkic languages, Turkic, Mongolic languages, ...
of testosterone is ''тестостерон''.


Brand names

Testosterone is marketed under a large number of brand names throughout the world. Major brand names of testosterone and/or its esters include Andriol, Androderm, AndroGel, Axiron, Delatestryl, Depo-Testosterone,
Intrinsa The testosterone patch, brand name Intrinsa among others, was designed to treat female sexual dysfunction. Mechanism of action Testosterone patches works by releasing the hormone testosterone through the skin into the bloodstream. In women, testost ...
, Nebido, Omnadren, Primoteston, Sustanon, Testim, TestoGel, TestoPatch, Testoviron, and Tostran.


Availability


United States

, unmodified (non-esterified) testosterone is available in the United States in the following formulations: * Topical gels: AndroGel, Fortesta, Testim, Testosterone (generic) * Topical solutions: Axiron, Testosterone (generic) * Transdermal patches: Androderm, Testoderm (discontinued), Testoderm TTS (discontinued), Testosterone (generic) *
Intranasal Nasal administration, popularly known as snorting, is a route of administration in which drugs are insufflated through the nose. It can be a form of either topical administration or systemic administration, as the drugs thus locally delivered ...
gels: Natesto * Buccal tablets: Striant * Pellet implants: Testopel And the following ester prodrugs of testosterone are available in the United States in oil solutions for intramuscular injection: * Testosterone cypionate: Depo-Testosterone, Testosterone Cypionate (generic) *
Testosterone enanthate Testosterone enanthate, sold under the brand names Delatestryl and Xyosted among others, is an androgen and anabolic steroid (AAS) medication which is used mainly in the treatment of low testosterone levels in men. It is also used in hormone th ...
: Delatestryl, Xyosted (auto-injector), Testosterone Enanthate (generic) * Testosterone propionate: Testosterone Propionate (generic) * Testosterone undecanoate: Aveed Unmodified testosterone was also formerly available for intramuscular injection but was discontinued. Testosterone cypionate and testosterone enanthate were formerly available in combination with estradiol cypionate and estradiol valerate, respectively, under the brand names Depo-Testadiol and Ditate-DS, respectively, as oil solutions for intramuscular injection, but these formulations have been discontinued. Unlike in Europe, Canada, and much of the rest of the world, oral testosterone undecanoate is not available in the United States.


Canada

, testosterone is available in Canada in the form of topical gels (AndroGel, Testim), topical solutions (Axiron), transdermal patches (Androderm), and intranasal gels (Natesto). Testosterone cypionate (Depo-Testosterone, Testosterone Cypionate (generic)), testosterone enanthate (Delatestryl, PMS-Testosterone Enanthate), and testosterone propionate (Testosterone Propionate (generic)) are available as oil solutions for intramuscular injection and testosterone undecanoate (Andriol, PMS-Testosterone, Taro-Testosterone) is available in the form of oral capsules. Testosterone buccal tablets and pellet implants do not appear to be available in Canada.


Other countries

Testosterone and/or its esters are widely available in countries throughout the world in a variety of formulations.


Legal status

Testosterone and its esters, along with other AAS, are
prescription-only A prescription drug (also prescription medication or prescription medicine) is a pharmaceutical drug that legally requires a medical prescription to be dispensed. In contrast, over-the-counter drugs can be obtained without a prescription. The rea ...
controlled substances in many countries throughout the world. In the United States, they are Schedule III drugs under the
Controlled Substances Act The Controlled Substances Act (CSA) is the statute establishing federal government of the United States, federal drug policy of the United States, U.S. drug policy under which the manufacture, importation, possession, use, and distribution of ...
, in Canada, they are Schedule IV drugs under the
Controlled Drugs and Substances Act The ''Controlled Drugs and Substances Act'' (french: Loi réglementant certaines drogues et autres substances) (the ''Act'') is Canada's federal drug control statute. Passed in 1996 under Prime Minister Jean Chrétien's government, it repeals ...
, and in the United Kingdom, they are Class C drugs under the Misuse of Drugs Act.


Litigation

, a number of lawsuits are underway against manufacturers of testosterone, alleging a significantly increased rate of stroke and heart attack in elderly men who use testosterone supplementation.


Doping in sports

There are many known cases of
doping in sports In competitive sports, doping is the use of banned athletic performance-enhancing drugs by athletic competitors as a way of cheating in sports. The term ''doping'' is widely used by organizations that regulate sporting competitions. The use of ...
with testosterone and its esters by
professional A professional is a member of a profession or any person who works in a specified professional activity. The term also describes the standards of education and training that prepare members of the profession with the particular knowledge and skil ...
athlete An athlete (also sportsman or sportswoman) is a person who competes in one or more sports that involve physical strength, speed, or endurance. Athletes may be professionals or amateurs. Most professional athletes have particularly well-devel ...
s.


Research


Depression

Testosterone has been used to treat depression in men who are of middle age with low testosterone. However, a 2014 review showed no benefit on the mood of the men with normal levels of testosterone or on the mood of the older men with low testosterone. Conversely, a 2009 review found that testosterone had an antidepressant effect in men with depression, especially those with hypogonadism, HIV/AIDS, and in the elderly.


Heart failure

Testosterone replacement can significantly improve
exercise capacity Exercise is a body activity that enhances or maintains physical fitness and overall health and wellness. It is performed for various reasons, to aid growth and improve strength, develop muscles and the cardiovascular system, hone athletic s ...
, muscle strength and reduce
QT interval The QT interval is a measurement made on an electrocardiogram used to assess some of the electrical properties of the heart. It is calculated as the time from the start of the Q wave to the end of the T wave, and approximates to the time taken ...
s in men with
chronic heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, a ...
(CHF). Over the 3 to 6-month course of the studies reviewed, testosterone therapy appeared safe and generally effective, and (ruling out prostate cancer) the authors found no justification to absolutely restrict its use in men with CHF. A similar 2012 review also found increased exercise capacity and reasoned the benefits generlizable to women. However, both reviews advocate larger, longer term,
randomized controlled trial A randomized controlled trial (or randomized control trial; RCT) is a form of scientific experiment used to control factors not under direct experimental control. Examples of RCTs are clinical trials that compare the effects of drugs, surgical te ...
s.


Male contraception

Testosterone, as esters such as testosterone undecanoate or testosterone buciclate, has been studied and promoted as a male contraceptive analogous to estrogen-based contraceptives in women. Otherwise considered an adverse effect of testosterone, reduced spermatogenesis can be further suppressed with the addition of a
progestin A progestogen, also referred to as a progestagen, gestagen, or gestogen, is a type of medication which produces effects similar to those of the natural product, natural female sex hormone progesterone in the body. A progestin is a ''synthetic co ...
such as
norethisterone enanthate Norethisterone enanthate (NETE), also known as norethindrone enanthate, is a form of hormonal birth control which is used to prevent pregnancy in women. It is used both as a form of progestogen-only injectable birth control and in combined inject ...
or levonorgestrel butanoate, improving the contraceptive effect.


Anorgasmia

Testosterone is under development in a low-dose intranasal formulation for the treatment of
anorgasmia Anorgasmia is a type of sexual dysfunction in which a person cannot achieve orgasm despite adequate stimulation. Anorgasmia is far more common in females (4.6 percent) than in males and is especially rare in younger men. The problem is greater in ...
in women.


Miscellaneous

Testosterone therapy may improve the management of
type 2 diabetes Type 2 diabetes, formerly known as adult-onset diabetes, is a form of diabetes mellitus that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent urination, ...
. Low testosterone has been associated with the development of
Alzheimer's disease Alzheimer's disease (AD) is a neurodegeneration, neurodegenerative disease that usually starts slowly and progressively worsens. It is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in short-term me ...
. Topical androgens like testosterone have been used and studied in the treatment of
cellulite Cellulite is the herniation of subcutaneous fat within fibrous connective tissue that manifests as skin dimpling and nodularity, often on the pelvic region (specifically the buttocks), lower limbs, and abdomen. Cellulite occurs in most postpubes ...
in women.


References


Further reading

* * * * * * *


External links

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