Effects of a novel finasteride 0.25% topical solution on scalp and serum dihydrotestosterone in healthy men with androgenetic alopecia

In 2015, two randomized, parallel-group studies were conducted to investigate the effects of a novel 0.25% finasteride topical solution on scalp and serum dihydrotestosterone (DHT) in men with androgenetic alopecia. The first study involved 18 men who received 1 mL of the solution once or twice a day, or a 1 mg oral tablet once a day for a week. The second study involved 32 men who received varying doses of the solution or a placebo for a week. The results showed that the solution reduced scalp DHT by 70% when applied once a day and by approximately 50% when applied twice a day or taken as a tablet. Serum DHT decreased by 60-70%. The 100 and 200 μL doses resulted in a 47-52% scalp DHT reduction, similar to the 300 and 400 μL doses. Serum DHT was reduced by only 24-26% with the 100 and 200 μL doses and by 44-48% with the 300 and 400 μL doses. No significant changes occurred for serum testosterone. The study concluded that the 0.25% finasteride solution applied once a day at the doses of 100 and 200 μL effectively inhibits scalp DHT, potentially minimizing the sexual side-effects linked to a systemic DHT reduction.