Does finasteride block dht? if does, does it also means no hair loss?

Yes and Maybe: Finateride, by inhibiting the enzyme (5-alpha-reductase) blocks the conversion of testosterone to dht. Depending on your unique genetic endowment and your lifetime exposure to stress and environmental toxins, it might prevent male pattern baldness. Given your young age, however, it might be wiser to consider natural 5 Alpha reductase inhibitors such as saw palmetto, pumpkin seed, and pygeum.

Finasteride: It works by preventing testosterone from being converted into Dht (dihydrotestosterone). In order to understand why inhibiting the production of Dht prevents hair loss and allows new hair to grow, one must first know why male pattern baldness occurs. You would take a 1/4 of a pill a day of finasteride.