Background: Androgenetic alopecia (male pattern hair loss) is caused by androgen-dependent miniaturization of scalp hair follicles, with scalp dihydrotestosterone (DHT) implicated as a contributing cause. Finasteride, an inhibitor of type II 5α-reductase, decreases serum and scalp DHT by inhibiting conversion of testosterone to DHT. Objective: Our purpose was to determine whether finasteride treatment leads to clinical improvement in men with male pattern hair loss. Methods: In two 1-year trials, 1553 men (18 to 41 years of age) with male pattern hair loss received oral finasteride 1 mg/d or placebo, and 1215 men continued in blinded extension studies for a second year. Efficacy was evaluated by scalp hair counts, patient and investigator assessments, and review of photographs by an expert panel. Results: Finasteride treatment improved scalp hair by all evaluation techniques at 1 and 2 years ( P 2 ) of balding vertex scalp, were observed with finasteride treatment (107 and 138 hairs vs placebo at 1 and 2 years, respectively; P Conclusion: In men with male pattern hair loss, finasteride 1 mg/d slowed the progression of hair loss and increased hair growth in clinical trials over 2 years. (J Am Acad Dermatol 1998;39:578-89.)

http://nnt.pharm.su.ac.th/dis/sites/default/files/answer/1443/Finasteride%20in%20the%20treatment%20of%20men%20with%20androgenic%20alopecia_0.pdf

Finasteride in the treatment of men with androgenetic alopecia

Preface 1. The medical and cultural history of testosterone and the testes Eberhard Nieschlag and Susan Nieschlag 2. Testosterone: biosynthesis, transport, metabolism and (non-genomic) actions C. Marc Luetjens and Gerhard F. Weinbauer 3. Pathophysiology of the androgen receptor Olaf Hiort, R. Werner and Michael Zitzmann 4. Methodology for measuring testosterone, DHT and SHBG in a clinical setting Manuela Simoni, Flaminia Fanelli, Laura Roli and Uberto Pagotto 5. The behavioral correlates of testosterone John Bancroft 6. The role of testosterone in spermatogenesis Liza O'Donnell and Robert I. McLachlan 7. Androgens and hair: a biological paradox with clinical consequences Valerie Anne Randall 8. Testosterone and bone Dirk Vanderschueren, Mieke Sinnesael, E. Gielen, F. Claessens and S. Boonen 9. Androgens effects on the skeletal muscle Shalender Bhasin, Ravi Jasuja, Carlo Serra, Rajan Singh, Thomas W. Storer, Wen Guo, Thomas G. Travison and Shezad Basaria 10. Testosterone and cardiovascular disease Kevin S. Channer and T. Hugh Jones 11. Testosterone, obesity, diabetes and the metabolic syndrome T. Hugh Jones and Kevin S. Channer 12. Testosterone and erection Mario Maggi and Hermann M. Behre 13. Testosterone and the prostate John T. Isaacs and Samuel R. Denmeade 14. Clinical use of testosterone in hypogonadism and other conditions Eberhard Nieschlag and Hermann M. Behre 15. Testosterone preparations for clinical use in males Hermann M. Behre and Eberhard Nieschlag 16. Androgens in male senescence Jean-Marc Kaufman, Guy T'Sojen and Alex Verleulen 17. Androgen therapy in non-gonadal disease David J. Handelsman 18. Review of guidelines on diagnosis and treatment of testosterone deficiency Ronald S. Swerdloff and Christina C. L. Wang 19. Pathophysiology of estrogen action in men Vincenzo Rochira, Daniele Santi and Cesare Carani 20. Dehydroepiandrosterone (DHEA) and androstenedione Bruno Allolio, Wiebke Arlt and Stefanie Hahner 21. The state-of-the-art in the development of selective androgen receptor modulators (SARMs) Ravi Jasuja, M. Zacharov and Shalender Bhasin 22. The essential role of testosterone in hormonal male contraception Eberhard Nieschlag and Hermann M. Behre 23. Testosterone use in women Susan R. Davis 24. Detection of illegal use of androgens and SARMs Wilhelm Schanzer and Mario Thevis 25. Clinical effects of doping with anabolic steroids Elena Vorona and Eberhard Nieschlag Index.

Testosterone : action, deficiency, substitution

Androgens are required for sexual hair and sebaceous gland development. However, pilosebaceous unit (PSU) growth and differentiation require the interaction of androgen with numerous other biological factors. The pattern of PSU responsiveness to androgen is determined in the embryo. Hair follicle growth involves close reciprocal epithelial-stromal interactions that recapitulate ontogeny; these interactions are necessary for optimal hair growth in culture. Peroxisome proliferator-activated receptors (PPARs) and retinoids have recently been found to specifically affect sebaceous cell growth and differentiation. Many other hormones such as GH, insulin-like growth factors, insulin, glucocorticoids, estrogen, and thyroid hormone play important roles in PSU growth and development. The biological and endocrinological basis of PSU development and the hormonal treatment of the PSU disorders hirsutism, acne vulgaris, and pattern alopecia are reviewed. Improved understanding of the multiplicity of factors involved in normal PSU growth and differentiation will be necessary to provide optimal treatment approaches for these disorders.

Role of Hormones in Pilosebaceous Unit Development

Air pollution and skin diseases: Adverse effects of airborne particulate matter on various skin diseases

http://www.haaronline.com/onderzoek/de_werking_van_haaruitval.pdf

Molecular mechanisms of androgenetic alopecia.

The need for a widely accepted, accurate, and reproducible standard of classification for male pattern baldness has increased with the advent and increasing popularity of hair transplant surgery. This report establishes such a classification, and reports its use in determining the incidence of male pattern baldness at various ages in 1,000 white adult male subjects. The action of testosterone as an incitant in male pattern baldness is well known, but this study points out the continued effect of time, even in later years. Since most hair transplant surgery is peformed on subjects with male pattern baldness, and because the success of hair transplant surgery is largely dependent on proper patient selection, a complete understanding of male pattern baldness is essential for consistently good results with hair transplantation.

O’Tar T. Norwood

Papers

Male pattern baldness: classification and incidence.

Male Pattern Baldness: Classification and Incidence