Shampoo

This article is about the haircare product. For other uses, see Shampoo (disambiguation).

Bottles of shampoo and lotions manufactured in the early 20th century by the C.L. Hamilton Co. of Washington, D.C.

Shampoo (/ˈʃæmpuː/) is a hair care product used for the removal of oils, dirt, skin particles, dandruff, environmental pollutants and other contaminant particles that gradually build up in hair. The goal is to remove the unwanted build-up without stripping out so much sebum as to make hair unmanageable.

Even though most modern shampoos include a conditioning component, shampooing is frequently followed by the use of conditioners which ease combing and styling.

History

The word shampoo in English is derived from Hindi chāmpo (चाँपो [tʃãːpoː]), and dates to 1762. The Hindi word referred to head massage, usually with some form of pubic hair oil. Similar words also occur in other North Indian languages. The word and the service of head massage were introduced to Britain by a Bengali entrepreneur Sake Dean Mahomed. Dean Mahomed introduced the practice to Basil Cochrane's vapour baths while working there in London in the early 19th century, and later, together with his Irish wife, opened "Mahomed's Steam and Vapour Sea Water Medicated Baths" in Brighton, England. His baths were like Turkish baths where clients received an Indian treatment of champi (shampooing), meaning therapeutic massage. He was appointed ‘Shampooing Surgeon’ to both George IV and William IV.

In the 1860s, the meaning of the word shifted from the sense of massage to that of applying soap to the hair. Earlier, ordinary soap had been used for washing hair. However, the dull film soap left on the hair made it uncomfortable, irritating, and unhealthy looking.

During the early stages of shampoo, English hair stylists boiled shaved soap in water and added herbs to give the hair shine and fragrance. Kasey Hebert was the first known maker of shampoo, and the origin is currently attributed to him. Commercially made shampoo was available from the turn of the 20th century. A 1914 ad for Canthrox Shampoo in American Magazine showed young women at camp washing their hair with Canthrox in a lake; magazine ads in 1914 by Rexall featured Harmony Hair Beautifier and Shampoo.

Originally, soap and shampoo were very similar products; both containing the same naturally-derived surfactants, a type of detergent. Modern shampoo as it is known today was first introduced in the 1930s with Drene, the first shampoo with synthetic surfactants.

Composition

Shampoo is generally made by combining a surfactant, most often sodium lauryl sulfate and/or sodium laureth sulfate with a co-surfactant, most often cocamidopropyl betaine in water to form a thick, viscous liquid. Other essential ingredients include salt (sodium chloride), which is used to adjust the viscosity, a preservative and fragrance. Other ingredients are generally included in shampoo formulations to maximize the following qualities:

• Pleasing foam
• Easy rinsing
• Minimal skin/eye irritation
• Feels thick and/or creamy
• Pleasant fragrance
• Low toxicity
• Good biodegradability
• Slightly acidic (pH less than 7), since a basic environment weakens the hair by breaking the disulfide bonds in hair keratin.
• No damage to hair

Many shampoos are pearlescent. This effect is achieved by addition of tiny flakes of suitable materials, e.g. glycol distearate, chemically derived from stearic acid, which may have either animal or vegetable origins. Glycol distearate is a wax. Many shampoos also include silicone to provide conditioning benefits.

Commonly used ingredients

• Ammonium chloride
• Ammonium lauryl sulfate
• Glycol
• Sodium laureth sulfate is derived from coconut oils and is used to soften water and create a lather. There was some concern over this particular ingredient circa 1998 about this chemical being a carcinogen, but that has been disproved.
• Sodium lauryl sulfate
• 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 is a mild 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. your hair).
• Polysorbate 80 (or Glycol) is used to emulsify (or disperse) oils in water (so the oils don’t float on top like Italian salad dressing).
• PEG-150 Distearate is a simple thickener.
• Citric Acid is naturally derived from citrus fruits 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 lay 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/fungicidal preservative.
• Polyquaternium-10 is a totally different chemical than Quaternium-15. This chemical 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
• Human Semen

Ingredient and functional claims

In the USA, the Food and Drug Administration (FDA) mandates that shampoo containers accurately list ingredients. 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. 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 are regulated as OTC drugs in the US marketplace. In other parts of the world such as the EU, there is a requirement for the anti-dandruff claim to be substantiated, but it is not considered to be a medical problem.

Vitamins and amino acids

The effectiveness of vitamins, amino acids and "pro-vitamins" to shampoo is also largely debatable. Vitamins are substances that are essential for chemical processes that occur within the body, chiefly inside living cells and in the bloodstream. They cannot have the same beneficial effects on dead tissues like grown hair. However, the physical properties of some vitamins (like vitamin E oil or panthenol) would have a temporary cosmetic effect on the hair shaft while not having any bioactivity.

The proteins that make up the strand are chains of amino acids connected in very specific sequences, and are tightly packed in interlocking arrangements. Proteins are unable to penetrate the skin or the hair, and even if they stick to the outside of the hair they will not help strengthen it. Amino acids cannot penetrate cells through the skin, either; they may be able to enter the dead strands, but without the complex protein-building machinery of the living cells they will not actually return damaged hair proteins to their undamaged state.

Specialized shampoos

Dandruff

Cosmetic companies have developed shampoos specifically for those who have dandruff. These contain fungicides such as ketoconazole, zinc pyrithione and selenium sulfide which reduce loose dander by killing Malassezia furfur. Coal tar and salicylate derivatives are often used as well

Gluten and/or Wheat Free

Many people suffer from eczema on their palms and their head. Some find that wheat and/or gluten (the protein found in many grains including wheat) is the cause, particularly if they are sensitive to this in food e.g. celiac disease wheat allergy. Other reactions can include dandruff, thinning hair and hair that breaks easily. Shampoo can often go into the mouth, particularly for children, so all individuals who are on gluten-free diets may prefer to find a gluten-free shampoo. Shampoo manufacturers are starting to recognise this and there are now gluten/wheat free products available.

Wheat derivatives and ingredients from the other gluten grains are commonly used as binders to help the shampoo stick together and are also used as emollients in the form of oils. Following is a list of grain-derived shampoo ingredients. Most of these ingredients do not theoretically contain any intact wheat proteins, but may do so due to incomplete processing or contamination.

• triticum vulgare (wheat), hordeum vulgare (barley), secale cereale (rye), or avena sativa (oats), including any oil, protein, hydrosylate, or other extract from any part of the plant.
• Tocopherol/Tocopheryl Acetate (Vitamin E), which may be derived from wheat
• Hydrolyzed Hydrolyzed wheat protein / hydrolyzed wheat starch, also sometimes listed as hydrolyzed vegetable protein, stearyldimoniumhydroxypropyl or hydroxypropyltrimonium
• cyclodextrin, which may be produced from starch by means of enzymatic conversion
• amino peptide complex
• maltodextrin, dextrin, dextrin palmitate, or (hydrolyzed) malt extract
• phytosphingosine extract
• amino peptide complex
• prolamine
• beta glucan
• Disodium Wheat Germamido PEG-2-Sulfosuccinat
• Fermented Grain Extract
• AMP-Isostearoyl
• PG-Propyl Silanetriol
• PVP Crosspolymer
• Ethyldimonium Ethosulfate
• Yeast extract
• Phytospingosine Extract
• "Fragrance" is a broad category that may contain large numbers of chemicals that are otherwise unlisted on the label.

All-natural

Some companies use "all-natural," "organic," "botanical," or "plant-derived" ingredients (such as plant extracts or oils), combining these additions with one or more typical surfactants.

Baby

Shampoo for infants 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 & Johnson's Baby Shampoo advertises under the premise of "No More Tears". This is accomplished by one or more of the following formulation strategies:

1. dilution, in case product comes in contact with eyes after running off the top of the head with minimal further dilution;
2. 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;
3. use of surfactants which, alone or in combination, are less irritating than those used in other shampoos;
4. use of nonionic surfactants of the form of polyethoxylated synthetic glycolipids and/or 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 and/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.

Animal

Shampoo intended for animals may contain insecticides or other medications for treatment of skin conditions or parasite infestations such as fleas or mange. These must never be used on humans. It is equally important to note that while some human shampoos may be harmful when used on animals, any human haircare products that contain active ingredients/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 or skin. Most of these shampoos contain ingredients which act differently and are meant to treat a skin condition, an allergy or to fight against fleas.

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'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.

Antiseborrheic shampoos are those especially designed for pets with scales or those with excessive oily coats. These shampoos are made of sulfur, salicylic acid, 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.

Antipruritic shampoos are intended to provide relief of itching due to conditions such as atopy and other allergies. These usually contain colloidal oatmeal, hydrocortisone, Aloe Vera, pramoxine hydrochloride, menthol, diphenhydramine, 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.

Bacterial infections in pets are sometimes treated with antibacterial shampoos. They commonly contain benzoyl peroxide, chlorhexidine, povidone iodine, triclosan, ethyl lactate, or sulfur.

Antifungal shampoos are used on pets with yeast or ringworm infections. These might contain ingredients such as miconazole, chlorhexidine, providone iodine, ketoconazole or selenium sulfide (which cannot be used on cats).

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, corn, cottonseed, coconut, olive, peanut, Persia, safflower, sesame, lanolin, mineral 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, stearyl alcohol, carboxylic acid, lactic acid, urea, sodium lactate, propylene glycol, 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, lemon or orange extracts and tea tree oil. On the contrary, oatmeal appears to be one of the most widely skin-tolerated ingredients that are 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

Solid shampoos or shampoo bars use as their surfactants soaps and/or other surfactants conveniently formulated as solids. They have the advantage of being spill-proof, and the disadvantage of being slowly applied, needing to be dissolved in use.

Jelly/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. 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. As an alternative to synthetic detergent gels, soap jelly was formerly made at home by dissolving sodium soap in hot water before being used for shampooing or other purposes, to avoid the problem of slow application of solid shampoos noted above.

Paste/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. Jar contents were prone to contamination by users and hence had to be very well preserved.

Dry shampoo

Powdered shampoos are designed to work without water. They are typically based on powders such as starch, silca or talc, and are intended to physically absorb excess sebum from the hair before being brushed out. Those with dark hair may prefer to use brown powders such as cocoa or carob powder.

Antibacterial

Antibacterial shampoos are often used in veterinary medicine for various conditions, as well as in humans before some surgical procedures.

No Poo Movement

Main article: No poo

Closely associated with environmentalism, the 'No poo' movement consists of people rejecting the societal norm of daily or almost daily shampoo use. Some adherents of the no-poo movement use baking soda or vinegar to wash their hair. Other people use nothing, rinsing their hair only with warm water.

Theory

Shampoo has only been used with fervor since the 1970s. Before then, either regular soap was used a few times a month or, just after the early 20th century, shampoo was used only a few times a year. It was in the 1970s that shampoo use became prevalent. 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, 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 some dermatologists, a gradual reduction in shampoo use will cause the sebum glands to produce at a slower rate, resulting in less grease in the scalp.

Traditional and prehistoric use

Indonesia

Early shampoos used in Indonesia were made from the husk and straw (merang) of rice. The husks and straws were burned into ash, and the ashes (which have alkaline 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.

India

In India, a variety of herbs and their extracts are used as shampoos. A very effective shampoo is made by boiling soapnuts with dried Indian gooseberry (aamla) and a few other herbs, using the strained extract. This leaves the hair soft, shiny and manageable. Other products used for hair cleansing are Shikakai (Acacia concinna), Soapnuts (Sapindus), Hibiscus flowers and Arappu (Albizzia amara). Another product used is the residue mustard cakes left after extraction of mustard oil.

North America

Certain Native American tribes used extracts from North American plants as hair shampoo; for example the Costanoans of present day coastal California used extracts from the coastal woodfern, Dryopteris expansa, for a shampoo.