The effects of transdermal dihydrotestosterone in the aging male: a prospective, randomized, double blind study

The objective of the study was to investigate the effects of dihydrotestosterone (DHT) gel on general well-being, sexual function, and the prostate in aging men. A total of 120 men participated in this randomized, placebo-controlled study (60 DHT and 60 placebo). All subjects had nocturnal penile tumescence once per week or less, andropause symptoms, and a serum T level of 15 nmol/liter or less and/or a serum SHBG level greater than 30 nmol/liter. The mean age was 58 yr (range, 50-70 yr). Of these subjects, 114 men completed the study. DHT was administered transdermally for 6 months, and the dose varied from 125-250 mg/d. General well-being symptoms and sexual function were evaluated using a questionnaire, and prostate symptoms were evaluated using the International Prostate Symptoms Score, transrectal ultrasonography, and assay of serum prostate-specific antigen. Early morning erections improved transiently in the DHT group at 3 months of treatment (P < 0.003), and the ability to maintain erection improved in the DHT group compared with the placebo group (P < 0.04). No significant changes were observed in general well-being between the placebo and the DHT group. Serum concentrations of LH, FSH, E2, T, and SHBG decreased significantly during DHT treatment. Treatment with DHT did not affect liver function or the lipid profile. Hemoglobin concentrations increased from 146.0 +/- 8.2 to 154.8 +/- 11.4 g/liter, and hematocrit from 43.5 +/- 2.5% to 45.8 +/- 3.4% (P < 0.001). Prostate weight and prostate-specific antigen levels did not change during the treatment. No major adverse events were observed. Transdermal administration of DHT improves sexual function and may be a useful alternative for androgen replacement. As estrogens are thought to play a role in the pathogenesis of prostate hyperplasia, DHT may be beneficial, compared with aromatizing androgens, in the treatment of aging men.