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
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
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
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
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
As the cells are squashed together and keratinized, the chemical
bonds form and hold the hair fiber into the shape of the hair
Hence curly hair follicles make curly hair fibers. Don't ask what
makes curly hair follicles because we don't know! There might
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
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.
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
products contain humectants and mild cleansing agents while avoiding
harsh plant oils or harsh detergents such as sodium lauryl sulfate.
differences in hair fiber and hair follicles references
- Lee HJ, Ha SJ,
Lee JH, Kim JW, Kim HO, Whiting DA. Hair counts from scalp biopsy
specimens in Asians. J Am Acad Dermatol. 2002 Feb;46(2):218-21.
- Loussouarn G.
African hair growth parameters. Br J Dermatol. 2001 Aug;145(2):294-7.
- Khumalo NP, Doe
PT, Dawber RP, Ferguson DJ. What is normal black African hair?
A light and scanning electron-microscopic study. J Am Acad Dermatol.
2000 Nov;43(5 Pt 1):814-20.
- Sperling LC.
Hair density in African Americans. Arch Dermatol. 1999 Jun;135(6):656-8.
- Lucky AW, Biro FM, Daniels SR, Cedars MI, Khoury
PR, Morrison JA. The prevalence of upper lip hair in black and
white girls during puberty: a new standard. J Pediatr. 2001 Jan;138(1):134-6.
- Pavlov IV. [Study of transverse sections
and pigment granules of the hair of persons of various nationalities].
Sud Med Ekspert. 1989 Jan-Mar;32(1):35-6.
- Nikolaeva SS, Dubinskaia VA. [Physico-chemical
properties of head hair of people of European and Negroid races].
Sud Med Ekspert. 1989 Apr-Jun;32(2):17-20.
- Dekio S, Jidoi J. Hair low-sulfur protein
composition does not differ electrophoretically among different
races. J Dermatol. 1988 Oct;15(5):393-6.
- Lindelof B, Forslind B, Hedblad MA, Kaveus U.
Human hair form. Morphology revealed by light and scanning electron
microscopy and computer aided three-dimensional reconstruction.
Arch Dermatol 1988 Sep;124(9):1359-63
- Eckes LK. [Body hair: an atavistic relic]?
Hautarzt. 1987 Mar;38(3):125-30.
- Eriksson AW, Frants RR, Kirjaranta M, Kajanoja
P. Studies on hair pigmentation and blood groups in the Bashkirs.
Ann Acad Sci Fenn A. 1986;175:25-32.
- Eckes LK. [Ethnic variations of scalp hair].
Hautarzt. 1985 Jul;36(7):381-5.
- Das-Chaudhuri AB, Chopra VP. Variation
in hair histological variables: medulla and diameter. Hum Hered.
- Bhatia RY, Rao KV, Rao NP. Site variations
in scalp hair morphology in pre-school children. Indian J Med
Res. 1980 Jun;71:890-2.
- Pandey AK, Saran S, Shukla R. Medullary
structure of head hair in Gurkha: a Mongoloid population of Dehra
Dun, India. Anthropol Anz. 1980 Aug;38(3):206-11.
- Lee LD, Ludwig K, Baden HP. Matrix proteins of
human hair as a tool for identification of individuals. Forensic
Sci. 1978 Mar-Apr;11(2):115-21.
- Hrdy DB, Baden HP, Lee LD, Kubilus J, Ludwig
KW. Frequency of an electrophoretic variant of hair alpha keratin
in human populations. Am J Hum Genet. 1977 Jan;29(1):98-100.
- Rook A. Hair II Racial and other genetic
variations in hair form. Br J Dermatol. 1975 May;92(5):599-600.
- Das BM. A study of cross sections of head
hair from some caucasoid and mongoloid populations of Assam, India.
Z Morphol Anthropol. 1974 Feb;65(3):324-8.
- Kerley ER, Rosen SI. The identification
of Polynesian head hair. J Forensic Sci. 1973 Oct;18(4):351-5.
- Hrdy D. Quantitative hair form variation
in seven populations. Am J Phys Anthropol. 1973 Jul;39(1):7-17.
- Hrdy D, Baden HP. Biochemical variation of hair
keratins in man and non-human primates. Am J Phys Anthropol. 1973
- Setty LR. Hair patterns of the external
surface of the nose of American Negro and white males. J Natl
Med Assoc. 1973 May;65(3):214-5.
- Setty LR. The distribution of posterior
cervical hair in white and Negro males. J Natl Med Assoc. 1972
- Stybalkowski M. [Microscopy studies of
cross-sections of head hair of Sevettijarvi-Skolt Laplanders].
Anthropol Anz. 1972 Jun;33(3):219-32.
- Gold RJ, Scriver CG. The amino acid composition
of hair from different racial origins. Clin Chim Acta. 1971 Jul;33(2):465-6.
- Setty LR. Hair patterns of the face of
white and negro males. J Natl Med Assoc. 1971 Mar;63(2):128-31.
- Setty LR. Hair patterns of scalp of white
and Negro males. Am J Phys Anthropol. 1970 Jul;33(1):49-55.
- Setty LR. Scrotal hair patterns of Whites
and Negroes. J Natl Med Assoc. 1970 Mar;62(2):156-8.
- Wassermann HP. Ethnic differences in natural
melanoproteins. Dermatologica. 1970;141(1):44-8.
- Setty LR. Penile hair patterns of whites
and negroes. J Natl Med Assoc. 1969 Jan;61(1):67-9.
- Setty LR. The distribution of hair of the
lower limb in white and Negro males. Am J Phys Anthropol. 1968
- Bhalla V, Kaul SS. Occipital hair whorl
as a racial criterion: a critical assessment. Am J Phys Anthropol.
- Shimode T. Morphological studies of head
hair in Ainu. Sapporo Igaku Zasshi. 1968 Oct;34(4):181-215.
- Yonemoto Y. Studies on measurements of the scalp
tissue of the Japanese adult (I). Okajimas Folia Anat Jpn. 1968
- Banerjee AR. On variation of human head
hair: hair form and medullation. Z Morphol Anthropol. 1965 Sep;57(1):56-69.
- Setty LR. Variations of the hair patterns
of the chest of white males. J Natl Med Assoc. 1965 May;57(3):211-4.