Does finasteride lower testosterone?

No, finasteride (Propecia) increases testosterone.

Finasteride stops some testosterone from being turned into DHT. As a result, you may have an increase in testosterone levels (up to 25%) when you start taking it. But this increase doesn’t seem to cause any issues and may not have noticeable effects for most people.

Finasteride, erectile dysfunction, and low libido

However, finasteride may cause erectile dysfunction and low libido (sexual desire) in some men, despite the fact that it increases testosterone levels. It’s not clear why this happens, and it’s less common with low finasteride doses. But let your care team know if sex-related side effects are an issue for you. A different hair-loss treatment may be a better option.