What is the mechanism of action of finasteride in treating androgenic alopecia?

Finasteride’s effectiveness in treating androgenic alopecia, commonly known as male pattern baldness, primarily lies in its ability to inhibit the enzyme 5-alpha reductase. This enzyme is responsible for converting testosterone into dihydrotestosterone (DHT), a potent androgen that contributes significantly to hair follicle miniaturization and the reduction of hair density in individuals genetically predisposed to androgenic alopecia.

By inhibiting 5-alpha reductase, finasteride effectively lowers levels of DHT in the scalp, which helps to mitigate the harmful effects of DHT on hair follicles. This action not only stops further hair loss but can also lead to the regrowth of hair in some patients. The reduction of DHT can lead to an increase in hair follicle size due to a healthier environment for hair growth.

Therefore, the mechanism of action involving the inhibition of 5-alpha reductase is crucial for understanding how finasteride helps manage androgenic alopecia and why it is a key therapeutic option in this condition.