Clinical dose ranging studies with finasteride, a type 2 5alpha-reductase inhibitor, in men with male pattern hair loss

J Am Acad Dermatol. 1999 Oct;41(4):555-63.


Background: Androgenetic alopecia is a common condition of adult men. Finasteride, a type 2 5alpha-reductase inhibitor, decreases the formation of dihydrotestosterone from testosterone.

Objective: Two separate clinical studies were conducted to establish the optimal dose of finasteride in men with this condition.

Methods: Men from 18 to 36 years of age with moderate vertex male pattern hair loss received finasteride 5, 1, 0.2, or 0.01 mg/day or placebo based on random assignment. Efficacy was determined by scalp hair counts, patient self-assessment, investigator assessment, and assessment of clinical photographs. Safety was assessed by clinical and laboratory measurements and by analysis of adverse experiences.

Results: Efficacy was demonstrated for all end points for finasteride at doses of 0.2 mg/day or higher, with 1 and 5 mg demonstrating similar efficacy that was superior to lower doses. Efficacy of the 0.01 mg dose was similar to placebo. No significant safety issues were identified in the trials.

Conclusion: Finasteride 1 mg/day is the optimal dose for the treatment of men with male pattern hair loss and was subsequently identified for further clinical development.

Publication types

  • Clinical Trial
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 5-alpha Reductase Inhibitors*
  • Adolescent
  • Adult
  • Alopecia / blood
  • Alopecia / drug therapy*
  • Dihydrotestosterone / blood
  • Double-Blind Method
  • Enzyme Inhibitors / administration & dosage*
  • Finasteride / administration & dosage*
  • Hair / drug effects
  • Hair / growth & development
  • Humans
  • Male
  • Patient Satisfaction


  • 5-alpha Reductase Inhibitors
  • Enzyme Inhibitors
  • Dihydrotestosterone
  • Finasteride