Topical Finasteride for Hair Loss
Finasteride pills (Propecia etc) are FDA approved for the treatment of male balding. The drug reduces blood DHT and stops hair loss in 90 % of men. Side effects are the main limitation of finasteride.
In a new study about a topical formulation of finasteride for hair loss, DHT levels were reduced by similar amounts compared to finasteride pills. Will side effects be similar? Nobody knows. It's likely that side effects will be present. The only benefit of a topical formulation would be if side effects were lower.
A novel finasteride 0.25% topical solution for androgenetic alopecia: pharmacokinetics and effects on plasma androgen levels in healthy male volunteers. Caserini et al. Int J Clin Pharmacol Ther. 2014 Jul 30.