While higher testosterone levels help explain why baldness is common among men and uncommon among women, this is an incomplete picture of the underlying physiology. Rather, it is a testosterone metabolite called dihydrotestosterone (DHT) that contributes to male-pattern hair loss and mediates the discrepancy in baldness rates between sexes.
One of the most effective treatments for male-pattern hair loss is finasteride, a drug that inhibits the conversion of testosterone into DHT.[1] In fact, by blocking the metabolism of testosterone in this way, finasteride can increase testosterone levels,[2][3] further emphasizing the limitations of testosterone as a marker of hair loss risk.
Having very low levels of circulating testosterone can reduce the amount of DHT synthesized, explaining why women (and men with very low testosterone) seem more resistant to baldness.[4] However, it is not necessarily the case that alterations to testosterone levels within normal levels will automatically translate into changes in DHT levels or, more importantly, risk of hair loss.
References
- ^Kaufman KD, Olsen EA, Whiting D, Savin R, DeVillez R, Bergfeld W, Price VH, Van Neste D, Roberts JL, Hordinsky M, Shapiro J, Binkowitz B, Gormley GJFinasteride in the treatment of men with androgenetic alopecia. Finasteride Male Pattern Hair Loss Study Group.J Am Acad Dermatol.(1998-Oct)
- ^Olsen EA, Hordinsky M, Whiting D, Stough D, Hobbs S, Ellis ML, Wilson T, Rittmaster RS,The importance of dual 5alpha-reductase inhibition in the treatment of male pattern hair loss: results of a randomized placebo-controlled study of dutasteride versus finasteride.J Am Acad Dermatol.(2006-Dec)
- ^Uygur MC, Arik AI, Altuğ U, Erol DEffects of the 5 alpha-reductase inhibitor finasteride on serum levels of gonadal, adrenal, and hypophyseal hormones and its clinical significance: a prospective clinical study.Steroids.(1998-Apr)
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