A 'chemical depilatory' is a
cosmetic preparation used to remove the
hair from the
skin on the
human body. Currently, a common active ingredient is
calcium thioglycolate, which breaks down the
disulfide bonds in
keratin and weakens the hair so that it is easily scraped off where it emerges from the
hair follicle.
This break down reaction is affected by the
calcium hydroxide (an alkali). The resulting combination of calcium hydroxide and thioglycolic acid is calcium thioglycolate(CaTG). The calcium hydroxide is present in excess to enable the thioglycolic acid to react with the
cystine present in hair
protein. The reaction is 2SH-CH2-COOH(thioglycolic acid) +R-S-S-R(cystine)-----> 2R-SH + COOH CH2 SS CH2 COOH (dithiodiglycolic acid).
As the
epidermis is also rich in keratin, the skin may become irritated and sensitive if the preparation is left on for too long. Chemical depilatories are used primarily for the arms and legs. They should not be used on the face unless specifically listed for that purpose on the product's label.
Chemical depilatories are available in
gel,
cream,
lotion,
aerosol, roll-on, and
powder forms. Common brands include
Nair and
Veet.
Advantages
:
★ Inexpensive
:
★ Fast
:
★ Various strength products available to dissolve even the strongest of hairs
:
★ Can be done at home
:
★ Available
over-the-counter
Disadvantages
:
★ Effect lasts a short time. Regrowth appears generally within 2-5 days.
:
★ Dark-haired users may be left with a visible "shadow" of dark hair under skin.
:
★ Chemical depilatory creams are generally foul in odor and messy to use.
:
★ Can cause severe skin
irritation or
allergic reactions.
See also
★
Hair removal