Changes in hair weight in men with androgenetic alopecia after treatment with finasteride (1 mg daily): Three- and 4-year results

BackgroundWe previously reported the effects of finasteride on scalp hair weight and count over a 2-year period in men with androgenetic alopecia (AGA).ObjectiveOur purpose was to evaluate the effects of finasteride on hair weight and count over 4 years in men with AGA.MethodsMen with AGA were randomized to receive finasteride (1 mg/d) or placebo for 192 weeks. Results of the second (weeks 96-144) and third (weeks 144-192) extension periods are reported.ResultsFinasteride increased hair weight at 144 and 192 weeks (week 192: finasteride, 21.6% increase from baseline; placebo, 24.5% decrease from baseline; net increase in hair weight for finasteride vs placebo = 46.0%, P < .001). Hair count also increased with finasteride at 144 and 192 weeks (week 192: finasteride, 7.2% increase from baseline; placebo, 13.0% decrease from baseline; net increase in hair count for finasteride vs placebo = 20.3%, P < .05). Finasteride was generally well tolerated.LimitationsBecause this study was extended from its original 48-week duration to nearly 4 years, the sample size available for analysis decreased with time.ConclusionLong-term finasteride treatment led to sustained improvement in hair weight compared with placebo. Hair weight increased to a larger extent than hair count, implying that factors other than the number of hairs, such as increased growth rate (length) and thickness of hairs, contribute to the beneficial effects of finasteride in treated men.