
Shampoo () is a
hair care
Hair care or haircare is an overall term for hygiene and cosmetology involving the hair which grows from the human scalp, and to a lesser extent Facial hair, facial, Pubic hair, pubic and other body hair. Hair care routines differ according to a ...
product, typically in the form of a
viscous liquid, that is formulated to be used for cleaning (scalp)
hair
Hair is a protein filament that grows from follicles found in the dermis. Hair is one of the defining characteristics of mammals.
The human body, apart from areas of glabrous skin, is covered in follicles which produce thick terminal and ...
. Less commonly, it is available in solid bar format. ("
Dry shampoo" is a separate product.) Shampoo is used by applying it to wet hair, massaging the product in the hair, roots and scalp, and then rinsing it out. Some users may follow a shampooing with the use of
hair conditioner
Hair conditioner is a hair care cosmetic product used to improve the feel, texture, appearance and manageability of hair. Its main purpose is to reduce friction between strands of hair to allow smoother brushing or combing, which might otherwise ...
.
Shampoo is typically used to remove the unwanted build-up of
sebum
A sebaceous gland or oil 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 ...
(natural oils) in the hair without stripping out so much as to make hair unmanageable. Shampoo is generally made by combining a
surfactant
Surfactants are chemical compounds that decrease the surface tension or interfacial tension between two liquids, a liquid and a gas, or a liquid and a solid. The word ''surfactant'' is a Blend word, blend of "surface-active agent",
coined in ...
, most often
sodium lauryl sulfate or
sodium laureth sulfate, with a co-surfactant, most often
cocamidopropyl betaine in water. The
sulfate ingredient acts as a
surfactant
Surfactants are chemical compounds that decrease the surface tension or interfacial tension between two liquids, a liquid and a gas, or a liquid and a solid. The word ''surfactant'' is a Blend word, blend of "surface-active agent",
coined in ...
, trapping oils and other contaminants, similarly to
soap
Soap is a salt (chemistry), salt of a fatty acid (sometimes other carboxylic acids) used for cleaning and lubricating products as well as other applications. In a domestic setting, soaps, specifically "toilet soaps", are surfactants usually u ...
.
Shampoos are marketed to people with hair. There are also shampoos intended for animals that may contain
insecticide
Insecticides are pesticides used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. The major use of insecticides is in agriculture, but they are also used in home and garden settings, i ...
s or other
medication
Medication (also called medicament, medicine, pharmaceutical drug, medicinal product, medicinal drug or simply drug) is a drug used to medical diagnosis, diagnose, cure, treat, or preventive medicine, prevent disease. Drug therapy (pharmaco ...
s to treat skin conditions or
parasite
Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted str ...
infestations such as
flea
Flea, the common name for the order (biology), order Siphonaptera, includes 2,500 species of small flightless insects that live as external parasites of mammals and birds. Fleas live by hematophagy, ingesting the blood of their hosts. Adult f ...
s.
History
Indian subcontinent
In the Indian subcontinent, a variety of herbs and their extracts have been used as shampoos since ancient times. The first origin of shampoo came from the Indus Valley Civilization. A very effective early shampoo was made by boiling Sapindus with dried Indian gooseberry (amla) and a selection of other herbs, using the strained extract.
''Sapindus'', also known as soapberries or soapnuts, a tropical tree widespread in India, is called ''ksuna'' (Sanskrit: क्षुण) in ancient Indian texts and its fruit pulp contains
saponin
Saponins (Latin ''sapon'', 'soap' + ''-in'', 'one of') are bitter-tasting, usually toxic plant-derived secondary metabolites. They are organic chemicals that become foamy when agitated in water and have high molecular weight. They are present ...
s which are a natural surfactant. The extract of soapberries creates a lather which Indian texts called ''phenaka'' (Sanskrit: फेनक). It leaves the hair soft, shiny and manageable. Other products used for hair cleansing were shikakai (''
Acacia concinna''),
hibiscus
''Hibiscus'' is a genus of flowering plants in the Malva, mallow family, Malvaceae. The genus is quite large, comprising List of Hibiscus species, several hundred species that are Native plant, native to warm temperate, Subtropics, subtropical ...
flowers,
[Rahman, , Oxford University Press, , page 145] ritha (''
Sapindus mukorossi'') and arappu (''Albizzia amara'').
Guru Nanak
Gurū Nānak (15 April 1469 – 22 September 1539; Gurmukhi: ਗੁਰੂ ਨਾਨਕ; pronunciation: , ), also known as ('Father Nanak'), was an Indian spiritual teacher, mystic and poet, who is regarded as the founder of Sikhism and is t ...
, the founder and the first
Guru
Guru ( ; International Alphabet of Sanskrit Transliteration, IAST: ''guru'') is a Sanskrit term for a "mentor, guide, expert, or master" of certain knowledge or field. In pan-Indian religions, Indian traditions, a guru is more than a teacher: tr ...
of
Sikhism
Sikhism is an Indian religion and Indian philosophy, philosophy that originated in the Punjab region of the Indian subcontinent around the end of the 15th century CE. It is one of the most recently founded major religious groups, major religio ...
, made references to soapberry tree and soap in the 16th century.
Cleansing the hair and body massage (champu) during one's daily bath was an indulgence of early colonial traders in India. When they returned to Europe, they introduced the newly learned habits, including the hair treatment they called shampoo. The word ''
shampoo'' entered the English language from the
Indian subcontinent
The Indian subcontinent is a physiographic region of Asia below the Himalayas which projects into the Indian Ocean between the Bay of Bengal to the east and the Arabian Sea to the west. It is now divided between Bangladesh, India, and Pakista ...
during the
colonial era. It dated to 1762 and was derived from the
Hindi
Modern Standard Hindi (, ), commonly referred to as Hindi, is the Standard language, standardised variety of the Hindustani language written in the Devanagari script. It is an official language of India, official language of the Government ...
word (, ), itself derived from the
Sanskrit
Sanskrit (; stem form ; nominal singular , ,) is a classical language belonging to the Indo-Aryan languages, Indo-Aryan branch of the Indo-European languages. It arose in northwest South Asia after its predecessor languages had Trans-cultural ...
root (), which means 'to press, knead, or soothe'.
Ancient Mesopotamia
Ancient Mesopotamian tablets from the
Neo-Assyrian period
The Neo-Assyrian Empire was the fourth and penultimate stage of ancient Assyrian history. Beginning with the accession of Adad-nirari II in 911 BC, the Neo-Assyrian Empire grew to dominate the ancient Near East and parts of South Caucasus, Nort ...
document the use of medicated shampoo to treat scalp eruptions.
Europe
Sake Dean Mahomed, an Indian traveller, surgeon, and entrepreneur, is credited with introducing the practice of ''shampoo'' or "shampooing" to Britain. In 1814, Mahomed, with his Irish wife Jane Daly, opened the first commercial "shampooing" vapour masseur bath in England, in
Brighton
Brighton ( ) is a seaside resort in the city status in the United Kingdom, city of Brighton and Hove, East Sussex, England, south of London.
Archaeological evidence of settlement in the area dates back to the Bronze Age Britain, Bronze Age, R ...
. He described the treatment in a local paper as "The Indian Medicated Vapour Bath (type of Turkish bath), a cure to many diseases and giving full relief when everything fails; particularly Rheumatic and paralytic, gout, stiff joints, old sprains, lame legs, aches and pains in the joints".
This medical work featured testimonies from his patients, as well as the details of the treatment made him famous. The book acted as a marketing tool for his unique baths in Brighton and capitalised on the early 19th-century trend for seaside spa treatments.
During the early stages of shampoo in
Europe
Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...
, English
hair stylists boiled shaved
soap
Soap is a salt (chemistry), salt of a fatty acid (sometimes other carboxylic acids) used for cleaning and lubricating products as well as other applications. In a domestic setting, soaps, specifically "toilet soaps", are surfactants usually u ...
in
water
Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...
and added
herbs to give the hair shine and
fragrance. Commercially made shampoo was available from the turn of the 20th century. A 1914 advertisement for Canthrox Shampoo in ''American Magazine'' showed young women at camp washing their hair with Canthrox in a lake; magazine advertisements in 1914 by
Rexall featured Harmony Hair Beautifier and Shampoo.
In 1900, German perfumer and hair-stylist Josef Wilhelm Rausch developed the first liquid hair washing soap and named it "Champooing" in Emmishofen, Switzerland. Later, in 1919, J.W. Rausch developed an antiseptic chamomile shampooing with a pH of 8.5.
In 1927, liquid shampoo was improved for mass production by German inventor
Hans Schwarzkopf in Berlin; his name became a shampoo brand sold in Europe.
Originally,
soap
Soap is a salt (chemistry), salt of a fatty acid (sometimes other carboxylic acids) used for cleaning and lubricating products as well as other applications. In a domestic setting, soaps, specifically "toilet soaps", are surfactants usually u ...
and shampoo were very similar products; both containing the same naturally derived
surfactants, a type of
detergent
A detergent is a surfactant or a mixture of surfactants with Cleanliness, cleansing properties when in Concentration, dilute Solution (chemistry), solutions. There are a large variety of detergents. A common family is the alkylbenzene sulfonate ...
. Modern shampoo as it is known today was first introduced in the 1930s with ''Drene'', the first shampoo using synthetic surfactants instead of soap.
Indonesia
Early shampoos used in
Indonesia
Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...
were made from the
husk and
straw
Straw is an agricultural byproduct consisting of the dry wikt:stalk, stalks of cereal plants after the grain and chaff have been removed. It makes up about half of the crop yield, yield by weight of cereal crops such as barley, oats, rice, ry ...
(''merang'') of
rice
Rice is a cereal grain and in its Domestication, domesticated form is the staple food of over half of the world's population, particularly in Asia and Africa. Rice is the seed of the grass species ''Oryza sativa'' (Asian rice)—or, much l ...
. The husks and straws were burned into ash, and the ashes (which have
alkaline
In chemistry, an alkali (; from the Arabic word , ) is a basic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The ...
properties) are mixed with water to form
lather. The ashes and lather were scrubbed into the hair and rinsed out, leaving the hair clean, but very dry. Afterwards,
coconut oil was applied to the hair in order to moisturize it.
Philippines
Filipinos
Filipinos () are citizens or people identified with the country of the Philippines. Filipinos come from various Austronesian peoples, all typically speaking Filipino language, Filipino, Philippine English, English, or other Philippine language ...
have been traditionally using ''gugo'' before commercial shampoos were sold in stores. The shampoo is obtained by soaking and rubbing the bark of the vine ''Gugo'' (''
Entada phaseoloides''), producing a lather that cleanses the scalp effectively. ''Gugo'' is also used as an ingredient in
hair tonics.
Pre-Columbian North America
Certain
Native American tribes used extracts from North American plants as hair shampoo; for example the
Costanoans of present-day coastal
California
California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
used extracts from the
coastal woodfern, ''
Dryopteris expansa''.
Pre-Columbian South America
Before
quinoa
Quinoa (''Chenopodium quinoa''; , from Quechuan languages, Quechua ' or ') is a flowering plant in the Amaranthaceae, amaranth family. It is a herbaceous annual plant grown as a crop primarily for its edible seeds; the seeds are high in prote ...
can be eaten the
saponin
Saponins (Latin ''sapon'', 'soap' + ''-in'', 'one of') are bitter-tasting, usually toxic plant-derived secondary metabolites. They are organic chemicals that become foamy when agitated in water and have high molecular weight. They are present ...
must be washed out from the grain prior to cooking. Pre-Columbian
Andean
The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long and wide (widest between 18°S ...
civilizations used this soapy by-product as a shampoo.
Types
Shampoos can be classified into four main categories:
* ''deep cleansing shampoos'', sometimes marketed under descriptions such as volumizing, clarifying, balancing, oil control, or thickening, which have a slightly higher amount of detergent and create a lot of foam;
* ''conditioning shampoos'', sometimes marketed under descriptions such as moisturizing, 2-in-1, smoothing, anti-frizz, color care, and hydrating, which contain an ingredient like silicone or
polyquaternium-10 to smooth the hair;
* ''baby shampoos'', sometimes marketed as tear-free, which contain less detergent and produce less foam; and
* ''anti-dandruff shampoos'', which are medicated to reduce
dandruff.
Composition

Shampoo is generally made by combining a
surfactant
Surfactants are chemical compounds that decrease the surface tension or interfacial tension between two liquids, a liquid and a gas, or a liquid and a solid. The word ''surfactant'' is a Blend word, blend of "surface-active agent",
coined in ...
, most often
sodium lauryl sulfate or
sodium laureth sulfate, with a co-surfactant, most often
cocamidopropyl betaine in
water
Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...
to form a thick, viscous liquid. Other essential ingredients include salt (
sodium chloride
Sodium chloride , commonly known as Salt#Edible salt, edible salt, is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. It is transparent or translucent, brittle, hygroscopic, and occurs a ...
), which is used to adjust the viscosity, a
preservative
A preservative is a substance or a chemical that is added to products such as food products, beverages, pharmaceutical drugs, paints, biological samples, cosmetics, wood, and many other products to prevent decomposition by microbial growth or ...
and
fragrance. Other ingredients are generally included in shampoo formulations to maximize the following qualities:
* pleasing foam
* ease of rinsing
* minimal
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 animal coverings, such as the arthropod exoskeleton, have different ...
and
eye irritation
* thick or creamy feeling
* pleasant fragrance
* low
toxicity
Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacteria, bacterium, or plant, as well as the effect o ...
* good
biodegradability
* slight
acid
An acid is a molecule or ion capable of either donating a proton (i.e. Hydron, hydrogen cation, H+), known as a Brønsted–Lowry acid–base theory, Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis ...
ity (
pH less than 7)
* no damage to hair
* repair of damage already done to hair
Many shampoos are
pearlescent. This effect is achieved by the addition of tiny flakes of suitable materials, e.g.
glycol distearate, chemically derived from
stearic acid
Stearic acid ( , ) is a saturated fatty acid with an 18-carbon chain. The IUPAC name is octadecanoic acid. It is a soft waxy solid with the formula . The triglyceride derived from three molecules of stearic acid is called stearin. Stearic acid ...
, which may have either animal or vegetable origins. Glycol distearate is a wax. Many shampoos also include
silicone
In Organosilicon chemistry, organosilicon and polymer chemistry, a silicone or polysiloxane is a polymer composed of repeating units of siloxane (, where R = Organyl group, organic group). They are typically colorless oils or elastomer, rubber ...
to provide conditioning benefits.
Commonly used ingredients
*
Ammonium chloride
Ammonium chloride is an inorganic chemical compound with the chemical formula , also written as . It is an ammonium salt of hydrogen chloride. It consists of ammonium cations and chloride anions . It is a white crystalline salt (chemistry), sal ...
*
Ammonium lauryl sulfate
*
Glycol
*
Sodium laureth sulfate is derived from coconut oils and is used to soften water and create pleasing foam.
*
Hypromellose cellulose ethers are widely used as thickeners, rheology modifiers, emulsifiers and dispersants in Shampoo products.
*
Sodium lauroamphoacetate is naturally derived from coconut oils and is used as a cleanser and counter-irritant. This is the ingredient that makes the product tear-free.
*
Polysorbate 20 (abbreviated as
PEG(20)) is a mild glycol-based surfactant that is used to solubilize fragrance oils and essential oils, meaning it causes liquid to spread across and penetrate the surface of a solid (i.e. hair).
*
Polysorbate 80 (abbreviated as
PEG(80)) is a glycol used to emulsify (or disperse) oils in water so the oils do not float on top.
* PEG-150 distearate is a simple thickener.
*
Citric acid
Citric acid is an organic compound with the formula . It is a Transparency and translucency, colorless Weak acid, weak organic acid. It occurs naturally in Citrus, citrus fruits. In biochemistry, it is an intermediate in the citric acid cycle, ...
is produced biochemically and is used as an antioxidant to preserve the oils in the product. While it is a severe eye-irritant, the sodium lauroamphoacetate counteracts that property. Citric acid is used to adjust the pH down to approximately 5.5. It is a fairly weak acid which makes the adjustment easier. Shampoos usually are at pH 5.5 because at slightly acidic pH, the scales on a hair follicle lie flat, making the hair feel smooth and look shiny. It also has a small amount of preservative action. Citric acid, as opposed to any other acid, will prevent bacterial growth.
*
Quaternium-15 is used as a bacterial and fungicidal preservative.
*
Polyquaternium
Polyquaternium is the International Nomenclature for Cosmetic Ingredients designation for several polycationic polymers that are used in the personal care industry. Polyquaternium is a neologism used to emphasize the presence of quaternary a ...
-10 acts as the conditioning ingredient, providing moisture and fullness to the hair.
* Di-PPG-2 myreth-10 adipate is a water-dispersible
emollient that forms clear solutions with surfactant systems.
*
Chloromethylisothiazolinone, or CMIT, is a powerful
biocide
A biocide is defined in the European legislation as a chemical substance or microorganism intended to destroy, deter, render harmless, or exert a controlling effect on any harmful organism. The US Environmental Protection Agency (EPA) uses a sli ...
and preservative.
Benefit claims regarding ingredients
In the United States, the
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 respo ...
(FDA) mandates that shampoo containers accurately list ingredients on the products container. The government further regulates what shampoo manufacturers can and cannot claim as any associated benefit. Shampoo producers often use these regulations to challenge marketing claims made by competitors, helping to enforce these regulations. While the claims may be substantiated, however, the testing methods and details of such claims are not as straightforward. For example, many products are purported to protect hair from damage due to
ultraviolet radiation
Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of t ...
. While the ingredient responsible for this protection does block UV, it is not often present in a high enough concentration to be effective. The North American Hair Research Society has a program to certify functional claims based on third-party testing. Shampoos made for treating medical conditions such as
dandruff or
itchy scalp are regulated as
OTC drugs in the US marketplace.
In the European Union, there is a requirement for the anti-dandruff claim to be substantiated as with any other advertising claim, but it is not considered to be a medical problem.
Health risks
A number of contact
allergen
An allergen is an otherwise harmless substance that triggers an allergic reaction in sensitive individuals by stimulating an immune response.
In technical terms, an allergen is an antigen that is capable of stimulating a type-I hypersensitivi ...
s are used as ingredients in shampoos, and
contact allergy caused by shampoos is well known.
Patch test
A patch test is a diagnostic method used to determine which specific substances cause allergic inflammation of a patient's skin.
Patch testing helps identify which substances may be causing a delayed-type allergic reaction in a patient and ...
ing can identify ingredients to which patients are allergic, after which a physician can help the patient find a shampoo that is free of the ingredient to which they are allergic.
The US bans 11 ingredients from shampoos, Canada bans 587, and the EU bans 1328.
Specialized shampoos
Dandruff
Cosmetic companies have developed shampoos specifically for those who have
dandruff. These contain
fungicide
Fungicides are pesticides used to kill parasitic fungi or their spores. Fungi can cause serious damage in agriculture, resulting in losses of yield and quality. Fungicides are used both in agriculture and to fight fungal infections in animals, ...
s such as
ketoconazole
Ketoconazole, sold under the brand name Nizoral, among others, is an antiandrogen, antifungal drug, antifungal, and antiglucocorticoid medication used to treat a number of fungal infections. Applied to the skin it is used for fungal skin inf ...
,
zinc pyrithione and
selenium disulfide, which reduce loose dander by killing
fungi
A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...
like ''
Malassezia furfur''.
Coal tar
Coal tar is a thick dark liquid which is a by-product of the production of coke and coal gas from coal. It is a type of creosote. It has both medical and industrial uses. Medicinally it is a topical medication applied to skin to treat psoria ...
and
salicylate derivatives are often used as well.
Alternatives to medicated shampoos are available for people who wish to avoid synthetic fungicides. Such shampoos often use
tea tree oil
Tea tree oil, also known as melaleuca oil, is an essential oil with a fresh, camphoraceous odour and a colour that ranges from pale yellow to nearly colourless and clear. It is derived from the leaves of the tea tree, '' Melaleuca alternif ...
,
essential oil
An essential oil is a concentrated hydrophobic liquid containing volatile (easily evaporated at normal temperatures) chemical compounds from plants. Essential oils are also known as volatile oils, ethereal oils, aetheroleum, or simply as the ...
s or herbal extracts.
Colored hair
Many companies have also developed color-protection shampoos suitable for colored hair; some of these shampoos contain gentle cleansers according to their manufacturers. Shampoos for color-treated hair are a type of moisturizing shampoo.
Baby
Shampoo for
infant
In common terminology, a baby is the very young offspring of adult human beings, while infant (from the Latin word ''infans'', meaning 'baby' or 'child') is a formal or specialised synonym. The terms may also be used to refer to juveniles of ...
s and young children is formulated so that it is less irritating and usually less prone to produce a stinging or burning sensation if it were to get into the eyes.
For example,
Johnson's Baby Shampoo advertises under the premise of "No More Tears". This is accomplished by one or more of the following formulation strategies.
# dilution, in case the product comes in contact with eyes after running off the top of the head with minimal further dilution
# adjusting pH to that of non-stress tears, approximately 7, which may be a higher pH than that of shampoos which are pH adjusted for skin or hair effects, and lower than that of shampoo made of soap
# Use of surfactants which, alone or in combination, are less irritating than those used in other shampoos (e.g.
Sodium lauroamphoacetate)
# use of nonionic surfactants of the form of polyethoxylated synthetic glycolipids and polyethoxylated synthetic monoglycerides, which counteract the eye sting of other surfactants without producing the anesthetizing effect of alkyl polyethoxylates or alkylphenol polyethoxylates
The distinction in 4 above does not completely surmount the controversy over the use of shampoo ingredients to mitigate eye sting produced by other ingredients, or the use of the products so formulated. The considerations in 3 and 4 frequently result in a much greater multiplicity of surfactants being used in individual baby shampoos than in other shampoos, and the detergency or foaming of such products may be compromised thereby. The monoanionic sulfonated surfactants and viscosity-increasing or foam stabilizing alkanolamides seen so frequently in other shampoos are much less common in the better baby shampoos.
Sulfate-free shampoos
Sulfate-free shampoos are composed of natural ingredients and free from both
sodium lauryl sulfate and
sodium laureth sulfate.
These shampoos use alternative surfactants to cleanse the hair.
Animal
Shampoo intended for animals may contain
insecticide
Insecticides are pesticides used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. The major use of insecticides is in agriculture, but they are also used in home and garden settings, i ...
s or other medications for treatment of skin conditions or
parasite
Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted str ...
infestations such as
flea
Flea, the common name for the order (biology), order Siphonaptera, includes 2,500 species of small flightless insects that live as external parasites of mammals and birds. Fleas live by hematophagy, ingesting the blood of their hosts. Adult f ...
s or
mange. These must never be used on humans. While some human shampoos may be harmful when used on animals, any human haircare products that contain active ingredients or drugs (such as zinc in anti-dandruff shampoos) are potentially toxic when ingested by animals. Special care must be taken not to use those products on pets. Cats are at particular risk due to their instinctive method of grooming their fur with their tongues.

Shampoos that are especially designed to be used on
pets, commonly
dogs and
cats, are normally intended to do more than just clean the pet's
coat
A coat is typically an outer garment for the upper body, worn by any gender for warmth or fashion. Coats typically have long sleeves and are open down the front, and closing by means of buttons, zippers, hook-and-loop fasteners (AKA velcro), ...
or skin. Most of these shampoos contain ingredients which act different and are meant to treat a skin condition or an
allergy
Allergies, also known as allergic diseases, are various conditions caused by hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include Allergic rhinitis, hay fever, Food allergy, food al ...
or to fight against
flea
Flea, the common name for the order (biology), order Siphonaptera, includes 2,500 species of small flightless insects that live as external parasites of mammals and birds. Fleas live by hematophagy, ingesting the blood of their hosts. Adult f ...
s.
The main ingredients contained by pet shampoos can be grouped in insecticidals, antiseborrheic, antibacterials, antifungals,
emollients,
emulsifiers and
humectants. Whereas some of these ingredients may be efficient in treating some conditions, pet owners are recommended to use them according to their
veterinarian
A veterinarian (vet) or veterinary surgeon is a medical professional who practices veterinary medicine. They manage a wide range of health conditions and injuries in non-human animals. Along with this, veterinarians also play a role in animal r ...
's indications because many of them cannot be used on cats or can harm the pet if it is misused.
Generally, insecticidal pet shampoos contain
pyrethrin,
pyrethroids (such as permethrin and which may not be used on cats) and
carbaryl. These ingredients are mostly found in shampoos that are meant to fight against parasite infestations.
Antifungal shampoos are used on pets with yeast or
ringworm
Dermatophytosis, also known as tinea and ringworm, is a mycosis, fungal infection of the skin (a dermatomycosis), that may affect skin, hair, and nails. Typically it results in a red, itchy, scaly, circular rash. Hair loss may occur in the a ...
infections. These might contain ingredients such as
miconazole,
chlorhexidine
Chlorhexidine is a disinfectant and antiseptic which is used for skin disinfection before surgery and to disinfect surgical instruments. It is also used for cleaning wounds, preventing dental plaque, treating yeast infections of the mouth, and ...
,
providone iodine,
ketoconazole
Ketoconazole, sold under the brand name Nizoral, among others, is an antiandrogen, antifungal drug, antifungal, and antiglucocorticoid medication used to treat a number of fungal infections. Applied to the skin it is used for fungal skin inf ...
or
selenium sulfide (which cannot be used on cats).
Bacterial infections in pets are sometimes treated with antibacterial shampoos. They commonly contain
benzoyl peroxide,
chlorhexidine
Chlorhexidine is a disinfectant and antiseptic which is used for skin disinfection before surgery and to disinfect surgical instruments. It is also used for cleaning wounds, preventing dental plaque, treating yeast infections of the mouth, and ...
, povidone iodine,
triclosan,
ethyl lactate, or sulfur.
Antipruritic
Antipruritics, abirritants, or anti-itch drugs, are medications that inhibit itching (Latin: ''pruritus'').
Itching is often associated with sunburns, allergic reactions, eczema, psoriasis, chickenpox, Fungal infection in animals, fungal infections ...
shampoos are intended to provide relief of itching due to conditions such as atopy and other allergies. These usually contain colloidal
oatmeal
Oatmeal is a preparation of oats that have been dehusked, steamed, and flattened, or a coarse flour of hulled oat grains ( groats) that have either been milled (ground), rolled, or steel-cut. Ground oats are also called white oats. Steel- ...
,
hydrocortisone
Hydrocortisone is the name for the hormone cortisol when supplied as a medication. It is a corticosteroid and works as an anti-inflammatory and by immune suppression. Uses include conditions such as adrenocortical insufficiency, adrenogenit ...
,
Aloe vera
''Aloe vera'' () is a succulent plant species of the genus ''Aloe''. It is widely distributed, and is considered an invasive species in many world regions.
An evergreen perennial plant, perennial, it originates from the Arabian Peninsula, but ...
, pramoxine hydrochloride,
menthol,
diphenhydramine
Diphenhydramine, sold under the brand name Benadryl among others, is an antihistamine and sedative. Although generally considered sedating, diphenhydramine can cause paradoxical central nervous system stimulation in some individuals, particula ...
, sulfur or salicylic acid. These ingredients are aimed to reduce the inflammation, cure the condition and ease the symptoms at the same time while providing comfort to the pet.
Antiseborrheic shampoos are those especially designed for pets with scales or those with excessive oily coats. These shampoos are made of sulfur,
salicylic acid
Salicylic acid is an organic compound with the formula HOC6H4COOH. A colorless (or white), bitter-tasting solid, it is a precursor to and a active metabolite, metabolite of acetylsalicylic acid (aspirin). It is a plant hormone, and has been lis ...
, refined
tar (which cannot be used on cats),
selenium sulfide (cannot be used on cats) and benzoyl peroxide. All these are meant to treat or prevent seborrhea oleosa, which is a condition characterized by excess oils. Dry scales can be prevented and treated with shampoos that contain sulfur or salicylic acid and which can be used on both cats and dogs.
Emollient shampoos are efficient in adding oils to the skin and relieving the symptoms of a dry and itchy skin. They usually contain oils such as
almond
The almond (''Prunus amygdalus'', Synonym (taxonomy)#Botany, syn. ''Prunus dulcis'') is a species of tree from the genus ''Prunus''. Along with the peach, it is classified in the subgenus ''Amygdalus'', distinguished from the other subgenera ...
,
corn
Maize (; ''Zea mays''), also known as corn in North American English, is a tall stout Poaceae, grass that produces cereal grain. It was domesticated by indigenous peoples of Mexico, indigenous peoples in southern Mexico about 9,000 years ago ...
,
cottonseed,
coconut
The coconut tree (''Cocos nucifera'') is a member of the palm tree family (biology), family (Arecaceae) and the only living species of the genus ''Cocos''. The term "coconut" (or the archaic "cocoanut") can refer to the whole coconut palm, ...
,
olive
The olive, botanical name ''Olea europaea'' ("European olive"), is a species of Subtropics, subtropical evergreen tree in the Family (biology), family Oleaceae. Originating in Anatolia, Asia Minor, it is abundant throughout the Mediterranean ...
,
peanut
The peanut (''Arachis hypogaea''), also known as the groundnut, goober (US), goober pea, pindar (US) or monkey nut (UK), is a legume crop grown mainly for its edible seeds. It is widely grown in the tropics and subtropics by small and large ...
, Persia,
safflower,
sesame,
lanolin,
mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Mi ...
or
paraffin oil. The emollient shampoos are typically used with emulsifiers as they help distributing the emollients. These include ingredients such as
cetyl alcohol,
laureth-5,
lecithin, PEG-4 dilaurate,
stearic acid
Stearic acid ( , ) is a saturated fatty acid with an 18-carbon chain. The IUPAC name is octadecanoic acid. It is a soft waxy solid with the formula . The triglyceride derived from three molecules of stearic acid is called stearin. Stearic acid ...
,
stearyl alcohol,
carboxylic acid
In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an Substituent, R-group. The general formula of a carboxylic acid is often written as or , sometimes as with R referring to an organyl ...
,
lactic acid
Lactic acid is an organic acid. It has the molecular formula C3H6O3. It is white in the solid state and it is miscible with water. When in the dissolved state, it forms a colorless solution. Production includes both artificial synthesis as wel ...
,
urea
Urea, also called carbamide (because it is a diamide of carbonic acid), is an organic compound with chemical formula . This amide has two Amine, amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest am ...
,
sodium lactate,
propylene glycol
Propylene glycol ( IUPAC name: propane-1,2-diol) is a viscous, colorless liquid. It is almost odorless and has a faintly sweet taste. Its chemical formula is CH3CH(OH)CH2OH.
As it contains two alcohol groups, it is classified as a diol. An al ...
,
glycerin, or
polyvinylpyrrolidone.
Although some of the pet shampoos are highly effective, some others may be less effective for some condition than another. Yet, although natural pet shampoos exist, it has been brought to attention that some of these might cause
irritation to the skin of the pet. Natural ingredients that might be potential allergens for some pets include
eucalyptus
''Eucalyptus'' () is a genus of more than 700 species of flowering plants in the family Myrtaceae. Most species of ''Eucalyptus'' are trees, often Mallee (habit), mallees, and a few are shrubs. Along with several other genera in the tribe Eucalyp ...
,
lemon
The lemon (''Citrus'' × ''limon'') is a species of small evergreen tree in the ''Citrus'' genus of the flowering plant family Rutaceae. A true lemon is a hybrid of the citron and the bitter orange. Its origins are uncertain, but some ...
or
orange extracts and
tea tree oil
Tea tree oil, also known as melaleuca oil, is an essential oil with a fresh, camphoraceous odour and a colour that ranges from pale yellow to nearly colourless and clear. It is derived from the leaves of the tea tree, '' Melaleuca alternif ...
. On the contrary, oatmeal appears to be one of the most widely skin-tolerated ingredients that is found in pet shampoos. Most ingredients found in a shampoo meant to be used on animals are safe for the pet as there is a high likelihood that the pets will lick their coats, especially in the case of cats.
Pet shampoos which include
fragrances,
deodorants or colors may harm the skin of the pet by causing inflammations or irritation. Shampoos that do not contain any unnatural additives are known as
hypoallergenic shampoos and are increasing in popularity.
Solid shampoo bars
Invented in 1987 by Lush co-founder, Mo Constantine and cosmetic chemist, Stan Krystal, solid shampoos or shampoo bars can either be soap-based or use other plant-based surfactants, such as sodium cocoyl isethionate or sodium coco-sulfate combined with oils and waxes. Soap-based shampoo bars are high in pH (alkaline) compared to human hair and scalps, which are slightly acidic. Alkaline pH increases the friction of the hair fibres which may cause damage to the hair cuticle, making it feel rough and drying out the scalp.
Jelly and gel
Stiff, non-pourable clear gels to be squeezed from a tube were once popular forms of shampoo, and can be produced by increasing a shampoo's
viscosity
Viscosity is a measure of a fluid's rate-dependent drag (physics), resistance to a change in shape or to movement of its neighboring portions relative to one another. For liquids, it corresponds to the informal concept of ''thickness''; for e ...
. This type of shampoo cannot be spilled, but unlike a solid, it can still be lost down the drain by sliding off wet skin or hair.
Paste and cream
Shampoos in the form of pastes or creams were formerly marketed in jars or tubes. The contents were wet but not completely dissolved. They would apply faster than solids and dissolve quickly.
Antibacterial
Antibacterial shampoos are often used in
veterinary medicine for various conditions, as well as in humans before some
surgical procedures.
No Poo Movement
Closely associated with
environmentalism
Environmentalism is a broad philosophy, ideology, and social movement about supporting life, habitats, and surroundings. While environmentalism focuses more on the environmental and nature-related aspects of green ideology and politics, ecolog ...
, the "
no poo" movement consists of people rejecting the societal norm of frequent shampoo use. Some adherents of the no poo movement use
baking soda
Sodium bicarbonate (IUPAC name: sodium hydrogencarbonate), commonly known as baking soda or bicarbonate of soda (or simply “bicarb” especially in the UK) is a chemical compound with the formula NaHCO3. It is a salt (chemistry), salt compose ...
or
vinegar to wash their hair, while others use diluted honey. Further methods include the use of raw eggs (potentially mixed with salt water), rye flour, or chickpea flour dissolved in water. Other people use nothing or rinse their hair only with conditioner.
Theory
In the 1970s, ads featuring
Farrah Fawcett and
Christie Brinkley asserted that it was unhealthy not to shampoo several times a week. This mindset is reinforced by the greasy feeling of the scalp after a day or two of not shampooing. Using shampoo every day removes
sebum
A sebaceous gland or oil 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 ...
, the oil produced by the scalp. This causes the
sebaceous glands to produce oil at a higher rate, to compensate for what is lost during shampooing. According to Michelle Hanjani, a dermatologist at Columbia University, a gradual reduction in shampoo use will cause the sebum glands to produce at a slower rate, resulting in less grease in the scalp. Although this approach might seem unappealing to some individuals, many people try alternate shampooing techniques like baking soda and vinegar in order to avoid ingredients used in many shampoos that make hair greasy over time.
Whereas the use of baking soda for hair cleansing has been associated with hair damage and skin irritation, likely due to its high pH value and exfoliating properties, honey, egg, rye flour, and chickpea flour hair washes seem gentler for long-term use.
See also
*
Soap
Soap is a salt (chemistry), salt of a fatty acid (sometimes other carboxylic acids) used for cleaning and lubricating products as well as other applications. In a domestic setting, soaps, specifically "toilet soaps", are surfactants usually u ...
*
Dry shampoo
*
Baby shampoo
*
Hair conditioner
Hair conditioner is a hair care cosmetic product used to improve the feel, texture, appearance and manageability of hair. Its main purpose is to reduce friction between strands of hair to allow smoother brushing or combing, which might otherwise ...
*
Exfoliant
*
No Poo
References
External links
*
*
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{{Authority control
Drug delivery devices
Hairdressing
Indian inventions
Personal hygiene products
Toiletry