Relaxer
Encyclopedia
A relaxer is a type of lotion
or cream generally used by people with afro textured hair, which makes hair less curly and also easier to straighten
by chemically "relaxing" the natural curls. The active agent is usually a strong alkali
, although some formulations are based on ammonium thioglycolate
instead.
The relaxer is applied to the roots of the hair and remains in place for a "cooking" interval, during which it alters the hair's texture by a process of controlled damage to the protein structure. The hair can be significantly weakened by the physical overlap of excessive applications or by a single excessive one, leading to brittleness, breakage, or even widespread alopecia
.
When the relaxer has worked to the desired degree, the hair is rinsed clean. Regardless of formula, relaxers are always alkaline to some degree, so it is prudent to neutralize or even slightly acidify the hair with a suitable shampoo
immediately afterward. The prompt use of hair conditioner
is also important in order to replace some of the natural oils that were stripped away by the process.
which had been made with excess lye
.
A lye relaxer consists of sodium hydroxide (also known as NaOH or lye) mixed with water, petroleum jelly
, mineral oil
, and emulsifiers to create a creamy consistency. On application, the caustic "lye cream" permeates the protein structure of the hair and weakens its internal bonds, causing the natural curls to loosen out as the entire fiber swells open. No special deactivation step is required after washing the lye cream out, other than the routine pH adjustment and hair-conditioning.
Manufacturers vary the sodium hydroxide content of the solution from 5% to 10% and the pH between 10 and 14.
as a wider definition for "alkaline", lye relaxers may be labelled as "base" or "no base". In this instance, the "base" refers to a preliminary coating of petroleum jelly onto the scalp to protect it from being irritated or burned by the lye cream. "No base" creams have a lower concentration of lye and may be applied directly to the hair roots without requiring the protective "base" layer, although these weaker products may still irritate the skin of some people who must therefore coat their scalps beforehand anyway.
, lithium hydroxide
, or guanidine
hydroxide. The last of these is not pre-formulated, but rather is generated at the time of use by combining a cream containing calcium hydroxide
(slaked lime) with an "activating solution" of guanidine carbonate.
Another type of "no-lye" relaxer uses ammonium thioglycolate
, which is also known as perm salt for its use in permanent waves. Perm salt is a chemical reducing agent
which selectively weakens the hair's cystine
bonds instead of disrupting the entire protein, but strips out the natural oils even more thoroughly than the alkali hydroxide products. Afterward, the thioglycolate must be oxidized with a special solution of hydrogen peroxide
or sodium bromate
.
Lastly, in most relaxers sold for home use, the active agents are ammonium sulfite
and ammonium bisulfite (the two compounds are interchangeable, depending on the surrounding pH). These also selectively reduce the cystine bonds, but are much weaker and work more slowly. Nevertheless, their mild action minimizes (but does not entirely eliminate) collateral irritation to the skin.
, led to a class action lawsuit against the manufacturer, the World Rio Corporation Inc., when the acidic chemicals it contained caused scalp damage and/or hair loss to thousands of users. The product was eventually withdrawn from the market.
Lotion
A lotion is a low- to medium-viscosity, topical preparation intended for application to unbroken skin. By contrast, creams and gels have higher viscosity.Lotions are usually applied to external skin with bare hands, a clean cloth, cotton wool or gauze...
or cream generally used by people with afro textured hair, which makes hair less curly and also easier to straighten
Hair straightening
Hair straightening is a hair styling technique which involves the flattening and straightening of hair in order to give it a smooth, streamlined, and 'sleek' appearance. It may be accomplished by using hair irons and hot combs, chemical relaxers, Japanese hair straightening, or Brazilian hair...
by chemically "relaxing" the natural curls. The active agent is usually a strong alkali
Alkali
In chemistry, an alkali is a basic, ionic salt of an alkali metal or alkaline earth metal element. Some authors also define an alkali as a base that dissolves in water. A solution of a soluble base has a pH greater than 7. The adjective alkaline is commonly used in English as a synonym for base,...
, although some formulations are based on ammonium thioglycolate
Ammonium thioglycolate
Ammonium thioglycolate, also known as perm salt, is the chemical compound with the formula HSCH2CO2NH4.Being the salt of a weak acid and weak base, ammonium thioglycolic acid exists in solution as an equilibrium mixture of the salt itself as well as the free carboxylic acid thioglycolic acid and...
instead.
General usage
Hair relaxing, or lanthionization, can be performed by a professional cosmetologist in a salon, or at home with relaxer kits purchased from discount stores and pharmacies. As with hair dye, the treated portion of the hair moves away from the scalp as the new growth of untreated hair sprouts up from the roots, requiring periodic retreatment (about every 6–8 weeks) to maintain a consistent appearance.The relaxer is applied to the roots of the hair and remains in place for a "cooking" interval, during which it alters the hair's texture by a process of controlled damage to the protein structure. The hair can be significantly weakened by the physical overlap of excessive applications or by a single excessive one, leading to brittleness, breakage, or even widespread alopecia
Alopecia
Alopecia means loss of hair from the head or body. Alopecia can mean baldness, a term generally reserved for pattern alopecia or androgenic alopecia. Compulsive pulling of hair can also produce hair loss. Hairstyling routines such as tight ponytails or braids may induce Traction alopecia. Both...
.
When the relaxer has worked to the desired degree, the hair is rinsed clean. Regardless of formula, relaxers are always alkaline to some degree, so it is prudent to neutralize or even slightly acidify the hair with a suitable shampoo
Shampoo
Shampoo 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...
immediately afterward. The prompt use of hair conditioner
Hair conditioner
Hair conditioner is a hair care product that alters the texture and appearance of hair.-History:For centuries, natural oils have been used to condition human hair. These natural products are still used today, including essential oils such as tea tree oil and carrier oils such as jojoba oil...
is also important in order to replace some of the natural oils that were stripped away by the process.
Alkaline and Lye relaxers
Garrett Augustus Morgan, an African-American, observed that it is possible to change the basic structure of the hair shaft when certain chemicals penetrate the cortical layer. Hair relaxing products often require washing and combing with soapSoap
In chemistry, soap is a salt of a fatty acid.IUPAC. "" Compendium of Chemical Terminology, 2nd ed. . Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford . XML on-line corrected version: created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN...
which had been made with excess lye
Lye
Lye is a corrosive alkaline substance, commonly sodium hydroxide or historically potassium hydroxide . Previously, lye was among the many different alkalis leached from hardwood ashes...
.
A lye relaxer consists of sodium hydroxide (also known as NaOH or lye) mixed with water, petroleum jelly
Petroleum jelly
Petroleum jelly, petrolatum, white petrolatum or soft paraffin, CAS number 8009-03-8, is a semi-solid mixture of hydrocarbons , originally promoted as a topical ointment for its healing properties...
, mineral oil
Mineral oil
A mineral oil is any of various colorless, odorless, light mixtures of alkanes in the C15 to C40 range from a non-vegetable source, particularly a distillate of petroleum....
, and emulsifiers to create a creamy consistency. On application, the caustic "lye cream" permeates the protein structure of the hair and weakens its internal bonds, causing the natural curls to loosen out as the entire fiber swells open. No special deactivation step is required after washing the lye cream out, other than the routine pH adjustment and hair-conditioning.
Manufacturers vary the sodium hydroxide content of the solution from 5% to 10% and the pH between 10 and 14.
"Base" and "no base" formulas
Entirely distinct from the chemical concept of baseBase (chemistry)
For the term in genetics, see base A base in chemistry is a substance that can accept hydrogen ions or more generally, donate electron pairs. A soluble base is referred to as an alkali if it contains and releases hydroxide ions quantitatively...
as a wider definition for "alkaline", lye relaxers may be labelled as "base" or "no base". In this instance, the "base" refers to a preliminary coating of petroleum jelly onto the scalp to protect it from being irritated or burned by the lye cream. "No base" creams have a lower concentration of lye and may be applied directly to the hair roots without requiring the protective "base" layer, although these weaker products may still irritate the skin of some people who must therefore coat their scalps beforehand anyway.
"No lye" relaxers
Because of increasing awareness of the potential dangers of sodium hydroxide found in traditional relaxer formulas, many women have begun abandoning them. "No-lye" relaxers have become the preferred formula for those unwilling to give up relaxers completely. "No-lye" relaxers are of three main types. One type operates on the same general principle as lye relaxers but uses a slightly weaker alkaline agent, such as potassium hydroxidePotassium hydroxide
Potassium hydroxide is an inorganic compound with the formula KOH, commonly called caustic potash.Along with sodium hydroxide , this colorless solid is a prototypical strong base. It has many industrial and niche applications. Most applications exploit its reactivity toward acids and its corrosive...
, lithium hydroxide
Lithium hydroxide
Lithium hydroxide is an inorganic compound with the formula LiOH. It is a white hygroscopic crystalline material. It is soluble in water and slightly soluble in ethanol...
, or guanidine
Guanidine
Guanidine is a crystalline compound of strong alkalinity formed by the oxidation of guanine. It is used in the manufacture of plastics and explosives. It is found in urine as a normal product of protein metabolism. The molecule was first synthesized in 1861 by the oxidative degradation of an...
hydroxide. The last of these is not pre-formulated, but rather is generated at the time of use by combining a cream containing calcium hydroxide
Calcium hydroxide
Calcium hydroxide, traditionally called slaked lime, is an inorganic compound with the chemical formula Ca2. It is a colourless crystal or white powder and is obtained when calcium oxide is mixed, or "slaked" with water. It has many names including hydrated lime, builders lime, slack lime, cal, or...
(slaked lime) with an "activating solution" of guanidine carbonate.
Another type of "no-lye" relaxer uses ammonium thioglycolate
Ammonium thioglycolate
Ammonium thioglycolate, also known as perm salt, is the chemical compound with the formula HSCH2CO2NH4.Being the salt of a weak acid and weak base, ammonium thioglycolic acid exists in solution as an equilibrium mixture of the salt itself as well as the free carboxylic acid thioglycolic acid and...
, which is also known as perm salt for its use in permanent waves. Perm salt is a chemical reducing agent
Reducing agent
A reducing agent is the element or compound in a reduction-oxidation reaction that donates an electron to another species; however, since the reducer loses an electron we say it is "oxidized"...
which selectively weakens the hair's cystine
Cystine
Cystine is a dimeric amino acid formed by the oxidation of two cysteine residues that covalently link to make a disulfide bond. This organosulfur compound has the formula 2. It is a white solid, and melts at 247-249 °C...
bonds instead of disrupting the entire protein, but strips out the natural oils even more thoroughly than the alkali hydroxide products. Afterward, the thioglycolate must be oxidized with a special solution of hydrogen peroxide
Hydrogen peroxide
Hydrogen peroxide is the simplest peroxide and an oxidizer. Hydrogen peroxide is a clear liquid, slightly more viscous than water. In dilute solution, it appears colorless. With its oxidizing properties, hydrogen peroxide is often used as a bleach or cleaning agent...
or sodium bromate
Sodium bromate
Sodium bromate, the inorganic compound with the chemical formula of NaBrO3, is the sodium salt of bromic acid. It is a strong oxidant, mainly used in continuous or batch dyeing processes involving sulfur or vat dyes and as a hair-permagent, chemical agent, or gold solvent in gold mines when used...
.
Lastly, in most relaxers sold for home use, the active agents are ammonium sulfite
Ammonium sulfite
Ammonium sulfite is the ammonium salt of sulfurous acid with the chemical formula 2SO3.-Preparation:Ammonium sulfite can be prepared by the reaction of ammonia with sulfur dioxide in aqueous solution:-Uses:...
and ammonium bisulfite (the two compounds are interchangeable, depending on the surrounding pH). These also selectively reduce the cystine bonds, but are much weaker and work more slowly. Nevertheless, their mild action minimizes (but does not entirely eliminate) collateral irritation to the skin.
Commercial sale
Early in the 1800s hair relaxing products emerged, such as "G.A. brandi's hair Cream." Sale of "lye relaxers" began in 1971 by companies such as Proline. They also produced the first commercial "no lye relaxer" using potassium hydroxide in 1919. A product falsely marketed as chemical-free in the 1990s, the Rio Hair Naturalizer SystemRio Hair Naturalizer System
The Rio Hair Naturalizer System was a hair relaxer distributed by The World Rio Corporation Inc. It was available in two types; "Neutral" as well as another one that claimed to have a "Color Enhancement Formula" that contained a black hair dye...
, led to a class action lawsuit against the manufacturer, the World Rio Corporation Inc., when the acidic chemicals it contained caused scalp damage and/or hair loss to thousands of users. The product was eventually withdrawn from the market.
See also
- Afro textured hair
- Hair ironHair ironA hair iron or hair tong is a tool used to change the structure of the hair using heat. There are three general kinds: curling irons, used to make the hair curly, straightening irons, commonly called straighteners or flat irons, used to straighten the hair, and crimping irons, used to create crimps...
- Hair straighteningHair straighteningHair straightening is a hair styling technique which involves the flattening and straightening of hair in order to give it a smooth, streamlined, and 'sleek' appearance. It may be accomplished by using hair irons and hot combs, chemical relaxers, Japanese hair straightening, or Brazilian hair...
- Hot combHot combA hot comb is a metal comb that is used to straighten moderate or coarse hair and create a smoother hair texture.-Overview:...
- Natural hair