The side effects of taking finasteride mainly affect the sexual function of men, mainly the erectile function, so it is generally recommended that patients under 50 years of age with prostate enlargement do not take finasteride in the first place. The actual fact is that the actual androgenic hormones in the male body play a vital role in prostate enlargement, and finasteride, as a 5 alpha-reductase inhibitor, can inhibit the male hormones in the male body from turning into dihydrotestosterone, which leads to prostate enlargement, so it has an effect on the formation of androgens in the male body, which can cause the male androgen level to drop and thus affect the male sexual function.