Comparison of oral versus transdermal testosterone supplementation in hypogonadal men.

Objective: To compare mean serum total testosterone, bioavailable-testosterone, and dihydrotestosterone levels between transdermal testosterone and oral testosterone undecanoate treatment.

Methods: Multicentre, randomized, cross-over study; 44 men >18 years, testosterone ≤2.5 ng/mL. Two patches (Testopatch®) every other day in the morning or two capsules Pantestone® 40 mg bid in each 22-day period. Hormone serum levels of four blood samples over the first and last 48 h of each treatment period.

Results: Mean age 49 years. Mean testosterone before inclusion 1.99 ng/mL. Mean testosterone serum levels over the last 48 h of Testopatch treatment were superior to Pantestone (4.64 vs. 2.58 ng/mL, p<0.001). Testosterone trough levels at the end of each treatment period were significantly higher for Testopatch (3.15 vs. 2.45 ng/mL, p<0.01). Bioavailable-testosterone levels over the first and last 48 h of treatment were significantly greater with Testopatch than with Pantestone (p=0.001 and p<0.01). Dihydrotestosterone levels over the first and last 48 h of treatment (0.71 vs. 1.05 ng/mL and 0.68 vs. 0.89 ng/mL) as well as at trough (0.59 vs. 0.96 ng/mL) were significantly lower with Testopatch than with Pantestone (p<0.001, p<0.05, and p<0.001). SHBG levels decreased by Pantestone but not by Testopatch (p<0.001).

Conclusions: Testopatch was superior to Pantestone to increase testosterone and bioavailable-testosterone levels in hypogonadal men from the first days and throughout the three weeks of treatment. Pantestone increased dihydrotestosterone to a larger extent and decreased SHBG.