Percutaneous absorption of 5α-dihydrotestosterone in man

The distribution of 5α-dihydrotestosterone to the blood following application of a solution of this androgen to the skin in a hydro-alcoholic gel was studied in order to evaluate the adequacy of the percutaneous route in correcting androgen deficiencies. In 14 adult men, daily percutaneous administration of 5α-dihydrotestosterone (125 mg in 5 g gel) increases, on the average, 4 to 5 times its initial concentration in plasma. On the 14th day of treatment, repeated evaluations of plasma 5α-dihydrotestosterone, between 2 and 21 h after final administration of gel, demonstrated the stability of diurnal 5α-dihydrotestosterone levels and showed the regular distribution of the steroid from a presumably cutaneous reservoir. Plasma 5α-androstane-3α, 17β-diol levels evolve parallel to those of 5α-dihydrotestosterone. Plasma testosterone and luteinizing hormone, on the contrary, decrease considerably. No variation of follicle-stimulating-hormone is observed during treatment. The percutaneous absorption represents an interesting method for administration of a natural androgen in men, particularly because one avoids the deleterious effects of supra-physiological levels in the liver achieved with oral administration.