Oral Testosterone With and Without Concomitant Inhibition of 5α-Reductase by Dutasteride in Hypogonadal Men for 28 Days

The study involved 43 hypogonadal men, 32 of whom completed a 28-day trial examining the effects of oral testosterone (T) with and without the 5α-reductase inhibitor dutasteride (D). Participants were given varying doses of T with or without D, or D alone. Results indicated that T levels increased with all T-containing regimens, with the highest T and D combination leading to above-normal T levels. D co-administration suppressed dihydrotestosterone (DHT) and improved T bioavailability. Oral T alone reduced serum luteinizing hormone and follicle-stimulating hormone by 25% to 50%, except in the lowest T plus D dose group, and significantly decreased serum sex hormone-binding globulin (SHBG) by 50% in the 400 mg T groups. No significant adverse effects on hemoglobin, blood counts, serum chemistry, liver markers, or PSA were noted, although two serious adverse events occurred but were unrelated to the drug. The study suggests that oral T, with or without D, could be a viable therapy for testosterone deficiency, but longer-term studies are needed to confirm safety and efficacy.