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hair follicle growth rates

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Hair follicle growth rates by age and body region

Below is a brief table of hair growth rates defined for people of different age and by the region of the body where the growth rate analysis was made (after Myers 1951). Typically, females will have slightly faster growing scalp hair than males of the same age but slower growing hair elsewhere such as on the leg.

Age category Daily growth rate for scalp hair (mm) Daily growth rate for eyebrow hair (mm) Daily growth rate for thigh hair (mm)
Pre puberty 0.41 0.14 0.13
Adolescent/young adult 0.30 0.14 0.16
Mature adult 0.34 0.16 0.25
Retirement age 0.32 0.16 0.19

Thus the long hairs of the scalp have the fastest rate of hair growth whereas the short hairs as in the eyebrow have the slowest growth rate.


Hair follicle regeneration after plucking by body region

Below is a brief table showing the number of days it took for a hair follicle from which a hair was plucked to regenerate a new hair fiber.

Age category Regeneration rate for scalp hair (days) Regeneration rate for eyebrow hair (days) Regeneration rate for thigh hair (days)
Pre puberty 134 58 77
Adolescent/young adult 138 65 88
Mature adult 112 56 141
Retirement age 139 73 240

The average number of days required for regeneration of hairs in 90% of the follicles from which hairs were plucked was 129 in the crown of the scalp, 123 in the under arm, 121 in the thigh, 92 in the chin, and 64 in the eyebrow. Hairs of the scalp regenerate more quickly for males than females, but hairs of the under arm, and thigh regenerate more quickly in females than males. Regions in which hairs are long and grow at the fastest rate require the longest interval for regeneration.


Hair follicle growth rates references

  • Seago SV, Ebling FJ. The hair cycle on the human thigh and upper arm. Br J Dermatol. 1985 Jul;113(1):9-16.
  • Randall VA, Ebling FJ. Seasonal changes in human hair growth. Br J Dermatol. 1991 Feb;124(2):146-51.
  • Nagl W. Different growth rates of pigmented and white hair in the beard: differentiation vs. proliferation? Br J Dermatol. 1995 Jan;132(1):94-7.
  • Van Neste D, De Brouwer B, Dumortier M. Reduced linear hair growth rates of vellus and of terminal hairs produced by human balding scalp grafted onto nude mice. Ann N Y Acad Sci. 1991 Dec 26;642:480-2.
  • Astore IP, Pecoraro V, Pecoraro EG. The normal trichogram of pubic hair. Br J Dermatol. 1979 Oct;101(4):441-5.
  • Katz M, Wheeler KE, Radowsky M, Gordon W. Assessment of rate of hair growth using a simple trichometer. Med Biol Eng Comput. 1979 May;17(3):333-6.
  • Saadat M, Khan MA, Gutherlet RL, Heald FP. Measurements of hair in normal newborns. Pediatrics. 1976 Jun;57(6):960-2.
  • Pecoraro V, Astore I, Barman JM. Growth rate and hair density of the human axilla. A. Comparative study of normal males and females and pregnant and post-partum females. J Invest Dermatol. 1971 May;56(5):362-5.
  • Saitoh M, Uzuka M, Sakamoto M. Human hair cycle. J Invest Dermatol. 1970 Jan;54(1):65-81.
  • Priestley GC. Rates and duration of hair growth in the albino rat. J Anat. 1966 Jan;100(1):147-57.
  • Braun-Falco O. [Dynamics of normal and pathological hair growth]. Arch Klin Exp Dermatol. 1966;227(1):419-52.
  • Barman JM, Astore I, Pecoraro V. The normal trichogram of the adult. J Invest Dermatol. 1965;44:233-43.
  • Barth JH. Measurement of hair growth. Clin Exp Dermatol. 1986 Mar;11(2):127-38.
  • Munro DD. Hair growth measurement using intradermal sulfur 35 cystine. Arch Dermatol. 1966 Jan;93(1):119-22.
  • Myers RJ, Hamilton JB. Regeneration and rate of growth of hairs in man. Ann N Y Acad Sci. 1951 Mar 27;53:562-8.
  • Trotter M. The life cycles of hair in selected regions of the body. Am J Phys Anthrop. 1924;7:427-37.
  • Trotter M. Hair growth and shaving. Anat Rec. 1928;37:373-79.
  • Giovannini S. De la régénération des poils aprés l'epilation. Arch f Mikrosec Anat. 1890;36:528-64.
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