The effects of finasteride (Proscar) on hair growth, hair cycle stage, and serum testosterone and dihydrotestosterone in adult male and female stumptail macaques (Macaca arctoides)

J Clin Endocrinol Metab. 1994 Oct;79(4):991-6. doi: 10.1210/jcem.79.4.7962310.


Finasteride, a 5 alpha-reductase inhibitor, was administered orally (1 mg/ for 6 months to six male and five female stumptail macaques. Vehicle was given to five male and five female animals over the same period of time. Hair weights in a defined 1-in.2 area of frontal scalp were measured periodically every 1-2 months, and serum was collected for measurement of testosterone and dihydrotestosterone. In addition, scalp biopsies were taken before and 6 months after treatment to evaluate the micromorphometry of hair follicles. Results showed that both male and female serum dihydrotestosterone levels were significantly reduced (60-70%) by finasteride treatment. Both males and females showed statistically significant increases in mean hair weight over the treatment period compared to controls (P = 0.034). In addition, there was a statistically significant increase in mean follicle length (measured histologically in scalp biopsies) compared to baseline in the finasteride-treated animals (P = 0.028). These data show that an inhibition of 5 alpha-reductase in the stumptail macaque can reverse the balding seen with age in both the male and female animals.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Dihydrotestosterone / blood*
  • Female
  • Finasteride / pharmacology*
  • Hair / anatomy & histology
  • Hair / drug effects*
  • Hair / growth & development*
  • Macaca / physiology*
  • Male
  • Organ Size / drug effects
  • Reference Values
  • Testosterone / blood*


  • Dihydrotestosterone
  • Testosterone
  • Finasteride