Chemical depilatory

Related Terms

Bleaching, chemical depilatory, depilation, depilatories, electrolysis, epilation, fatlah, flashlamp, hair, hair waxing, Intense Pulsed Light, IPL, khite, laser hair removal, photoepilation, phototricholysis, plucking, rotary epilators, shaving, sugaring, threading, trimming, waxing.

Background

Hair removal is the process of taking off the threadlike covering that grows from the surface of the skin. Hair grows on all areas of the human body except for the palms of the hands, the lips, certain areas of the genitals and the soles of the feet. Hair usually is most noticeable in people in the following areas: the face, head, eyebrows, eyelashes, chest, abdomen, pubic area, legs, armpits and back. There are a number of processes for removing hair; most of these processes remove the hair only temporarily.
There are two general types of hair removal: depilation and epilation. Both are temporary solutions. Depilation is a generic term for hair removal that affects the part of the hair above the surface of the skin. Depilation may last several hours to several days and may be achieved by shaving or trimming (manually or with electric shavers), depilatories (creams or shaving powders that chemically dissolve hair) or friction (rough surfaces used to buff away hair). Epilation is removal of the entire hair, including the part below the skin. Epilation lasts several days to several weeks and can be achieved by: waxing (a hot or cold layer is applied and then removed with porous strips), plucking (hairs are plucked, or pulled out, with tweezers), sugaring (similar to waxing, but with a sticky paste), threading (also called fatlah or khite, in which a twisted thread catches hairs as it is rolled across the skin) or rotary epilators (devices which rapidly grasp hairs and pull them out by the root).
There are also permanent hair removal procedures available. Methods have been developed that use chemicals, energy of varying types or a combination to target the areas that regulate hair growth. Permanently destroying these areas while sparing surrounding tissue is a difficult challenge. Methods include: electrolysis, laser and flashlamp (also called Intense Pulsed Light or IPL). Lasting hair removal for many may require the continuous use of prescribed oral medications.
Hair removal has been practiced for centuries in many human cultures. The methods used vary among times and regions, but in the United States, shaving is the most popular form of hair removal. Reasons for hair removal have included: medical, social, cultural, sexual, religious, military or as punishment.

Theory / Evidence

Each hair is contained in a pilosebaceous unit, which consists of a hair shaft, hair follicle, sebaceous gland, and erector pili muscle. Hair growth and shedding is a continuous cycle with three phases: the anagen phase (growth), the catagen phase (transition), and the telogen phase (rest). Hairs spend a variable amount of time in each phase determined by genetics, hormones, and area of the body. Hair in the anagen phase is more susceptible to injury than hair in the telogen phase. All of these factors play a role in the different methods of hair removal.
Hair is normally removed for social and sexual reasons related to the social role of hair in human society. Many cultures have an aesthetic, ideal amount of hair for males and females. People whose hair violates such standards may experience real or perceived problems with social acceptance. Many men in Western cultures shave their facial hair. Some men shave because they cannot grow a full beard, because their beard color is different than scalp hair color or because it grows in many directions, making a groomed look difficult. Some men shave because their beards are very coarse, causing itchiness and irritation. Some men grow a beard from time to time to change their appearance. In many cultures, women frequently remove some or all of their body hair, believing it is unattractive and/or not feminine. Women may also remove some or all of their pubic hair for aesthetic or sexual reasons. Men may also practice this.
Some men shave their heads, either as a fashion statement, to cover up male pattern baldness, or to attain enhanced cooling of the skull (particularly for people suffering from hyperhidrosis- excessive sweating). A much smaller number of women also shave their heads as fashion or political statements. Head shaving is a part of the Buddhist, Christian, Muslim, Jain and Hindu traditions.
A close-cropped or completely shaven haircut is common in military organizations. In field environments, soldiers are susceptible to infestation of lice, ticks and fleas. Also, due to hectic operation schedules, time allowed for personal hygiene and grooming is highly curtailed or even absent. Some have also noted that the practice of head shaving serves to remove exterior signs of individual identity, which can be helpful in the process of cultivating a team-oriented environment. In many militaries, head shaving is mandatory for males upon induction training.
In some situations, a person's hair may be shaved as a punishment. After World War II, this was a common punishment in France for women who collaborated with the Nazis during the occupation. In Arab countries, shaving off beards and eyebrows is sometimes used to shame and humiliate male prisoners.
Patients' body hair was once shaved before surgery for reasons of hygiene; however, this turned out to be counter-productive and, as a result, patients are no longer shaved in many hospitals. The shaving of hair has sometimes been used in attempts to eradicate lice or to minimize body odor due to accumulation of odor-causing microorganisms in hair. Some people with trichiasis (ingrown eyelashes) find it medically necessary to remove the eyelashes.

Author information

This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

Bibliography

American Academy of Dermatology. 15 June 2006.
American Electrology Association. 15 June 2006.
Amin SP, Goldberg DJ. Clinical comparison of four hair removal lasers and light sources. J Cosmet Laser Ther. 2006 Jun;8(2):65-8.
Dermnet New Zealand: Electrolysis. 15 June 2006.
Shapiro J, Lui H. Treatments for unwanted facial hair. Skin Therapy Lett. 2005 Dec-2006 Jan;10(10):1-4.
Tanner J, Woodings D, Moncaster K. Preoperative hair removal to reduce surgical site infection. Cochrane Database Syst Rev. 2006 Apr 19;(2):CD004122.
Toosi P, Sadighha A, Sharifian A, et al. A comparison study of the efficacy and side effects of different light sources in hair removal. Lasers Med Sci. 2006 Apr;21(1):1-4.
Warner J, Weiner M, Gutowski KA. Laser hair removal. Clin Obstet Gynecol. 2006 Jun;49(2):389-400.

Technique

Depilatory creams: These are creams that, when applied and left on the skin for a specified amount of time, remove hair. Depilatory creams contain sodium thioglycolate and calcium thioglycolate to dissolve the keratin that makes up hair, resulting in its removal. These creams typically have a strong, unpleasant odor.
Electrolysis: This hair removal technique involves a hair-thin metal probe that is slid into a hair follicle. This probe does not puncture the skin because it fits directly into the hair follicle. Once the probe is in the follicle, electricity is delivered to the follicle through the probe. This electrical current causes localized damage to the areas that generate hair. Electrolysis is completed in several visits. The total number of visits depends on the hair that is being removed and varies from person to person. Each of these sessions lasts between 15 minutes and one hour. Electrolysis was invented more than 100 years ago to remove irritating or in-grown eyelash hairs. Most areas of the body can be treated with electrolysis including: the eyebrows, face, thighs, abdomen, breasts and legs.
Friction: In this method, a rough surface is used to buff away hair at the skin's surface. A mitt with rough strips or a smoothing surface coated directly onto it is typically used.
Laser hair removal: This treatment is an option for long term or permanent results. During the procedure, a doctor holds a hand-held laser against the patient's skin and activates it for a fraction of a second. The laser light passes through the skin's surface to the hair follicles, where it generates enough heat to destroy the follicles and the bulbs. If the procedure is successful, old hair falls out and new hair does not grow back, but this requires multiple treatments. Laser hair removal was tested for about 20 years before it became available commercially in the 1990s. Laser hair removal is best at removing darker hair. It attempts to cause localized damage to targeted hair follicles by selectively heating dark target matter in the area that causes hair growth while not heating the rest of the skin. Laser hair removal selects one of three chromophores (groups with characteristic optical absorptions): carbon, hemoglobin or melanin.
Plucking: Hair is grasped and pulled out with tweezers.
Rotary epilators: These devices are similar to electric razors except instead of a cutting plate on a rotary head, they have rows of tweezers that can pull hairs out by the root.
Shaving: Shaving is generally done in the bath or shower with a razor and often a shaving foam or gel. Shaving should be done in a smooth, down-up movement. Most experts consider it important to moisturize the skin after shaving. Results may only last one to three days.
Sugaring: A hair removal technique meant to be less painful than waxing. The sugar mixture is heated and spread in the direction of hair growth. The sugar is then covered with a cotton strip and pulled off in the opposite direction of hair growth. The results of sugaring generally last a few weeks.
Threading: Called khite in Arabic and fatlah in Egyptian, threading is a less common hair removal method in the West. It is primarily used for facial hair and removes hair at the root by yanking out rows of hair with twisted cotton threads. The practitioner holds one end of the cotton thread in his or her teeth and the other in the left hand. The middle is looped through the index and middle fingers of the right hand. The practitioner then uses the loop to trap a series of unwanted hairs and pull them from the skin. There are also devices made that can hold the thread during the procedure. It is inexpensive, fast and considered less painful than plucking for most. Results may last up to two to four weeks.
Waxing: This is a temporary method of removing hair from the root that may last up to eight weeks. Areas that are most commonly waxed include the eyebrows, face, bikini area, legs, arms and back. Waxing is normally accomplished by spreading a heated wax combination thinly over the skin. A cloth or paper strip is then pressed firmly on top of the wax and ripped off in a quick movement against the direction of hair growth. This method removes the wax, along with the hair and any dead skin cells in the area. This method can be performed at home or by professionals in a spa or salon.