![Banff Centre lotion and shampoo](https://upload.wikimedia.org/wikipedia/commons/6/65/Banff_Centre_lotion_and_shampoo.jpg)
Lotion is a low-
viscosity
The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water.
Viscosity quantifies the inte ...
topical preparation intended for application to the
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 ...
. By contrast,
creams and
gels
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 dif ...
have higher viscosity, typically due to lower water content.
Lotions are applied to external skin with bare hands, a brush, a clean cloth, or
cotton wool.
While a lotion may be used as a medicine delivery system, many lotions, especially hand lotions and body lotions and lotion for
allergies
Allergies, also known as allergic diseases, refer a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic derma ...
are meant instead to simply smooth, moisturize, soften and, sometimes, perfume the skin.
Some skincare products, such as
sunscreen and
moisturizer
A moisturizer, or emollient, is a cosmetic preparation used for protecting, moisturizing, and lubricating the skin. These functions are normally performed by sebum produced by healthy skin. The word "emollient" is derived from the Latin verb ''m ...
, may be available in multiple formats, such as lotions, gels, creams, or sprays.
Medicine delivery
![Calamine lotion](https://upload.wikimedia.org/wikipedia/commons/5/51/Calamine_lotion.png)
Dermatologists can prescribe lotions to treat or prevent skin diseases.
It is not unusual for the same drug ingredient to be formulated into a lotion,
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 ...
and
ointment. Creams are the most convenient of the three but inappropriate for application to regions of hairy skin such as the scalp, while a lotion is less viscous and may be readily applied to these areas (many medicated
shampoos
Shampoo () is a hair care product, typically in the form of a viscous liquid, that is used for cleaning hair. Less commonly, shampoo is available in solid bar format. Shampoo is used by applying it to wet hair, massaging the product into the ...
are in fact lotions). Historically, lotions also had an advantage in that they may be spread thinly compared to a cream or ointment and may economically cover a large area of skin, but product research has steadily eroded this distinction.
Non-comedogenic lotions are recommended for use on acne prone skin.
Lotions can be used for the delivery to the skin of medications such as:
*
Antibiotic
An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of ...
s
*
Antiseptic
An antiseptic (from Greek ἀντί ''anti'', "against" and σηπτικός ''sēptikos'', "putrefactive") is an antimicrobial substance or compound that is applied to living tissue/skin to reduce the possibility of infection, sepsis, or putre ...
s
*
Antifungals
An antifungal medication, also known as an antimycotic medication, is a pharmaceutical fungicide or fungistatic used to treat and prevent mycosis such as athlete's foot, ringworm, candidiasis (thrush), serious systemic infections such as cryp ...
*
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 ...
s
* Anti-
acne
Acne, also known as ''acne vulgaris'', is a long-term skin condition that occurs when dead skin cells and oil from the skin clog hair follicles. Typical features of the condition include blackheads or whiteheads, pimples, oily skin, and ...
agents
* Soothing, smoothing, moisturizing or protective agents (such as
calamine
Calamine, also known as calamine lotion, is a medication used to treat mild itchiness. This includes from sunburn, insect bites, poison ivy, poison oak, and other mild skin conditions. It may also help dry out skin irritation. It is applie ...
)
*Anti Allergens
Occupational use
Since health care workers must wash their hands frequently to prevent disease transmission, hospital-grade lotion is recommended to prevent skin
dermatitis
Dermatitis is inflammation of the skin, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened. The area of skin involved can v ...
caused by frequent exposure to cleaning agents in the soap. A 2006 study found that application of hospital-grade lotion after hand washing significantly reduced skin roughness and dryness.
Care must be taken not to use consumer lotions in a hospital environment, as the
perfume
Perfume (, ; french: parfum) is a mixture of fragrant essential oils or aroma compounds (fragrances), fixatives and solvents, usually in liquid form, used to give the human body, animals, food, objects, and living-spaces an agreeable scent. Th ...
s and
allergen
An allergen is a type of antigen that produces an abnormally vigorous immune response in which the immune system fights off a perceived threat that would otherwise be harmless to the body. Such reactions are called allergies.
In technical terms ...
s may be a danger to those who are immunodeficient or with allergies.
Cosmetic uses
Most cosmetic lotions are
moisturizing lotions, although other forms, such as
tanning lotion
Indoor tanning lotions accelerate the tanning process, by promoting the production of melanin. Increasing blood flow to the skin is a proposed mechanism, which may in turn stimulate production of melanin by melanocytes. Indoor tanning lotions u ...
, also exist.
Cosmetic lotions may be marketed as anti-aging lotions, which can also be classified as a cosmetic in many cases, and may contain fragrances. 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 respon ...
voiced concern about lotions not classified as drugs that advertise anti-aging or anti-wrinkle properties.
Production
Most lotions are oil-in-water
emulsion
An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Althoug ...
s using a substance such as
cetearyl alcohol
Cetostearyl alcohol, cetearyl alcohol or cetylstearyl alcohol is a mixture of fatty alcohols, consisting predominantly of cetyl (16 C) and stearyl alcohols (18 C) and is classified as a fatty alcohol. It is used as an emulsion stabilizer, op ...
to keep the emulsion together, but water-in-oil lotions are also formulated. The key components of a skin care lotion, cream or gel emulsion (that is mixtures of oil and water) are the
aqueous
An aqueous solution is a solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula. For example, a solution of table salt, or sodium chloride (NaCl), in water would be re ...
and oily phases, an
emulsifier
An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Altho ...
to prevent separation of these two phases, and, if used, the
drug
A drug is any chemical substance that causes a change in an organism's physiology or psychology when consumed. Drugs are typically distinguished from food and substances that provide nutritional support. Consumption of drugs can be via insuffla ...
substance or substances. Various other ingredients such as
fragrance
An aroma compound, also known as an odorant, aroma, fragrance or flavoring, is a chemical compound that has a smell or odor. For an individual chemical or class of chemical compounds to impart a smell or fragrance, it must be sufficiently ...
s,
glycerol
Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids known ...
,
petroleum jelly,
dyes,
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 by ...
s,
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
s and stabilizing agents are commonly added to lotions.
Manufacturing lotions and creams can be completed in two cycles:
*Emollients and lubricants are dispersed in oil with blending and thickening agents.
*Perfume, color and preservatives are dispersed in the water cycle. Active ingredients are broken up in both cycles depending on the raw materials involved and the desired properties of the lotion or cream.
A typical oil-in-water manufacturing process may be:
*Step 1: Add flake/powder ingredients to the oil being used to prepare the oil phase.
*Step 2: Disperse active ingredients.
*Step 3: Prepare the water phase containing emulsifiers and stabilizers.
*Step 4: Mix the oil and water to form an emulsion. (Note: This is aided by heating to between 110 and 185 F (45-85 C) depending on the formulation and viscosity desired.)
*Step 5: Continue mixing until the end product is 'completed'
Potential health risks
Acne
Depending on their composition, lotions can be comedogenic, meaning that they can result in the increased formation of
comedo
A comedo is a clogged hair follicle (pore) in the skin. Keratin (skin debris) combines with oil to block the follicle. A comedo can be open (blackhead) or closed by skin (whitehead) and occur with or without acne. The word "comedo" comes from the ...
nes (clogged hair follicles).
People who are prone to
acne
Acne, also known as ''acne vulgaris'', is a long-term skin condition that occurs when dead skin cells and oil from the skin clog hair follicles. Typical features of the condition include blackheads or whiteheads, pimples, oily skin, and ...
or forming comedones often prefer lotions that are designed to be non-comedogenic (not causing outbreaks).
Systemic absorption
All topical products, including lotions, can result in the
percutaneous (through the skin) absorption of their ingredients. Though this has some use as a route of drug administration, it more commonly results in unintended
side effect
In medicine, a side effect is an effect, whether therapeutic or adverse, that is secondary to the one intended; although the term is predominantly employed to describe adverse effects, it can also apply to beneficial, but unintended, consequence ...
s. For example, medicated lotions such as
diprolene are often used with the intention of exerting only
local effects, but absorption of the drug through the skin can occur to a small degree, resulting in systemic side effects such as
hyperglycemia
Hyperglycemia is a condition in which an excessive amount of glucose circulates in the blood plasma. This is generally a blood sugar level higher than 11.1 mmol/L (200 mg/dL), but symptoms may not start to become noticeable until even ...
and
glycosuria
Glycosuria is the excretion of glucose into the urine. Ordinarily, urine contains no glucose because the kidneys are able to reabsorb all of the filtered glucose from the tubular fluid back into the bloodstream. Glycosuria is nearly always caused ...
.
Absorption through the skin is increased when lotions are applied and then covered with an
occlusive
In phonetics, an occlusive, sometimes known as a stop, is a consonant sound produced by occluding (i.e. blocking) airflow in the vocal tract, but not necessarily in the nasal tract. The duration of the block is the ''occlusion'' of the consonan ...
layer, when they are applied to large areas of the body, or when they are applied to damaged or broken skin.
Allergens
Lotions containing some aromas or food additives may trigger an immune reaction or even cause users to develop new allergies.
There is currently no regulation over use of the term "hypoallergenic", and even pediatric skin products with the label were found to still contain allergens. Those with
eczema
Dermatitis is inflammation of the skin, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened. The area of skin involved can ...
are especially vulnerable to an allergic reaction with lotion, as their compromised skin barrier allows preservatives to bind with and activate immune cells.
The
American Academy of Allergy, Asthma, and Immunology
Founded in 1943, the American Academy of Allergy, Asthma & Immunology (AAAAI) is a professional medical membership organization of nearly 6,800 allergist/ immunologists and related professionals around the world with advanced training and experie ...
released a warning in 2014 that natural lotion containing ingredients commonly found in food (such as goats milk, cow's milk, coconut milk, or oil) may introduce new allergies, and an allergic reaction when those foods are later consumed.
A paper published in 2020 by researchers at
St. George's, University of London found that "frequent skin moisturization in early life might promote the development of food allergy, most likely through transcutaneous sensitization".
See also
*
Cold cream
Cold cream is an emulsion of water and certain fats, usually including beeswax and various scent agents, designed to smooth skin and remove makeup. Cold cream is an emulsion of water in a larger amount of oil, unlike the oil in water emulsion of ...
*
Barrier cream
A barrier cream is a topical formulation used in industrial applications and as a cosmetic to place a physical barrier between the skin and contaminants that may irritate the skin (contact dermatitis or occupational dermatitis). There are many o ...
References
External links
Lotions during the early 19th century
{{cosmetics
Dosage forms
Drug delivery devices
Skin care
Emollients and protectives
Toiletry