Dictionary Definition
relaxer n : any agent that produces relaxation;
"music is a good relaxer"
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Extensive Definition
A relaxer is a type of lotion or cream which straightens
hair by chemically "relaxing" the natural curls. The active
agent is usually a strong alkali, although some
formulations are based on ammonium
thioglycolate 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 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 successive 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.
Types of hair relaxers
Lye relaxers
Alkaline relaxers were informally discovered in the United States during the 19th century, when African-Americans observed that their hair's texture could be altered by washing and combing it with soap which had been made with excess lye. Proline, the manufacturers of Dark and Lovely, officially "invented" the commercial "lye relaxer" in 1971.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 factor between 10 and
14.
"Base" and "no base" formulas
Entirely distinct from the chemical concept of base as a synonym 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
"No-lye" relaxers are of three main types. One type operates on the same general principle as lye relaxers but use a slightly weaker alkaline agent, such as potassium hydroxide, 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.