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ethnic differences in hair fiber and hair follicles

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Ethnic differences in hair fiber and hair follicles

Each individual is unique and hair production rate, size, and shape differs for everyone, but in general there are some differences in the nature of hair fiber for people of different ethnic backgrounds.

Asian hair is on average the thickest and most coarse hair compared to Caucasian and African American hair. It is almost always straight and circular in cross section. The density of Asian hair on the scalp (follicles per unit area of skin) is less than that typically observed in Caucasians. The density of hair follicles in African Americans is also somewhat lower than for Caucasians on average. At the lowest end of the spectrum the density of Asian may be just 90,000 scalp follicles and rarely gets above 120,000 scalp follicles.

Caucasian hair can be quite variable in its presentation with straight, wavy or curly hair. The fiber can be circular or oval in cross section and is on average thinner than Asian hair. Hair follicle density varies and density can be approximately related to hair color. Red haired people have the least dense scalp hair growth of Caucasians, blonds the most dense and brown haired people somewhere in the middle. Denstiy can range from 100,000-150,000 scalp hair follicles

African American hair is frequently tightly coiled, or spiral hair. In cross section it is elliptical or almost flat and ribbon-like in some cases. This means that there is more strength and rigidity to the fiber across the area of greatest cross section but the hair is much more pliable across the narrow section. This results in the curls of hair all naturally flexing and coiling along the ribbon while there is little or no coiling from side to side.

Different hair fiber types are produced by different hair follicles. Large, straight hair follicles with a circular cross section produce thick straight hair. Curly, flat hair follicles make curly elliptical or ribbon shaped cross section hair. Many African Americans have very curly, flattened hair follicles in their skin that produce highly coiled hair. Some research suggests that the hair follicles are actually spiral/spring shaped if you were able to look down the length of these hair follicles.

The shape of the hair follicle acts as a mold for the creation of the hair fiber. Deep in the hair follicle, where cells are added to the fiber at the root, the hair is soft and pliable. The cells of the fiber take the shape of the surrounding hair follicle sheath. As the cells are squashed together and keratinized, the chemical bonds form and hold the hair fiber into the shape of the hair follicle. Hence curly hair follicles make curly hair fibers. Don't ask what makes curly hair follicles because we don't know! There might also be racial differences in the chemical composition of the fiber. Some research studies suggest African American hair has a greater amount of low sulfur protein compared to high sulfur protein than observed in Asian or Caucasian individuals. However, other more recent studies have not found a significant difference in the sulfur content of hair fiber from people of different ethnicities.

People with very coiled hair often claim it seems to weather more rapidly with cuticle flaking and deterioration in hair quality. In part this is probably due to the coling putting stress on the hair fiber cuticle. The outer side of a coiled hair has cuticle that is stretched thin and the scales are relatively exposed and easy to catch and damage as when bushing for example. In contrast, the cuticle in the inner side of a coiled hair is relatively thick and scrunched together. Because the hair on the outer side of the coil is so thin and stretched it takes less physical or chemcial action to flake and damage the cuticle exposing the softer cortex of the hair underneath.

If anything, African American hair follicles produce more oils and sebum than follicles in other ethnic groups, but the oils are not evenly distributed along the length of the hair fiber because of its coiled shape. As a result, the hair fiber is typically very dry Consequently, African Americans are more likely to need hair oils to supplement their natural oil production and help keep the hair fiber flexible. In addition, tight spiral hair is difficult to brush and comb. Using oils helps reduce the friction and static from combing and make the hair more manageable. African Americans often find they need to use specially formulated oils and shampoos. African American hair responds differently than Caucasian and Asian hair and preferred grooming products contain humectants and mild cleansing agents while avoiding harsh plant oils or harsh detergents such as sodium lauryl sulfate.

Ethnic differences in hair fiber and hair follicles references

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