Hair removal

Hair removal, also known as epilation or depilation, is the deliberate removal of body hair.

Hair typically grows all over the human body. Hair can become more visible during and after puberty and men tend to have thicker, more visible body hair than women. Both men and women have visible hair on the head, eyebrows, eyelashes, armpits, pubic region, arms, and legs; men also have thicker hair on their face, abdomen, back and chest. Hair does not generally grow on the lips, the underside of the hands or feet or on certain areas of the genitalia.

Forms of hair removal are practised for various and mostly cultural, sexual, medical or religious reasons. Forms of hair removal have been practised in almost all human cultures since at least the Neolithic era. The methods used to remove hair have varied in different times and regions, but shaving is the most common method.

Cultural and sexual aspects

Each culture of human society has developed social norms relating to the presence or absence of body hair, which has changed from one time to another. Different standards can apply to males and females. People whose hair falls outside a culture's aesthetic standards may experience real or perceived social acceptance problems. For example, for women in several societies, exposure in public of body hair other than head hair, eyelashes and eyebrows is generally considered to be unaesthetic, unattractive and embarrassing. In Middle Eastern societies, removal of the female body hair has been considered proper hygiene, necessitated by local customs, for many centuries.

Hair

Hair is a protein filament that grows from follicles found in the dermis, or skin. Hair is one of the defining characteristics of mammals. The human body, apart from areas of glabrous skin, is covered in follicles which produce thick terminal and fine vellus hair. Most common interest in hair is focused on hair growth, hair types and hair care, but hair is also an important biomaterial primarily composed of protein, notably keratin. Attitudes towards hair, such as hairstyles and hair removal, vary widely across different cultures and historical periods, but it is often used to indicate a person's personal beliefs or social position, such as their age, gender, or religion.

Overview

The word "hair" usually refers to two distinct structures:

Pubic hair

Pubic hair is the hair in the frontal genital area of adolescent and adult humans, located on and around the sex organs, the crotch, and sometimes at the top of the inside of the thighs, in the pubic region around the pubis bone.

Although fine vellus hair is present in the area in childhood, pubic hair is considered to be the heavier, longer and coarser hair that develops during puberty as an effect of rising levels of androgens. Pubic hair is therefore part of the androgenic hair (or body hair) and is a secondary sex characteristic. Many cultures regard pubic hair to be erotic while in most cultures, both men and women are expected to cover their pubic hair at all times.

Development

The Tanner scale looks at the development of pubic hair. Before the onset of puberty, the genital area of both boys and girls has very fine vellus hair, referred to as Tanner stage 1 hair. As puberty begins, the body produces rising levels of the sex hormones, and in response the skin of the genital area begins to produce thicker and rougher, often curlier, hair with a faster growth rate. The onset of pubic hair development is termed pubarche. The change for each hair follicle is relatively abrupt, but the extent of skin which grows androgenic hair gradually increases over several years.

Laser hair removal

Laser hair removal is the process of removing unwanted hair by means of exposure to pulses of laser light that destroy the hair follicle. It had been performed experimentally for about twenty years before becoming commercially available in the mid-1990s. One of the first published articles describing laser hair removal was authored by the group at Massachusetts General Hospital in 1998. The efficacy of laser hair removal is now generally accepted in the dermatology community, and laser hair removal is widely practiced in clinics, and even in homes using devices designed and priced for consumer self-treatment. Many reviews of laser hair removal methods, safety, and efficacy have been published in the dermatology literature.

Mechanism of action

The primary principle behind laser hair removal is selective photothermolysis (SPTL), the matching of a specific wavelength of light and pulse duration to obtain optimal effect on a targeted tissue with minimal effect on surrounding tissue. Lasers can cause localized damage by selectively heating dark target matter, melanin, in the area that causes hair growth, the follicle, while not heating the rest of the skin. Light is absorbed by dark objects, so laser energy can be absorbed by dark material in the skin, but with much more speed and intensity. This dark target matter, or chromophore, can be naturally-occurring or artificially introduced.