There are two types of estrogen use in men. In the first case, when men who have not reached puberty take estrogen, male secondary sex characteristics will not appear as they grow and develop, but female secondary sex characteristics will appear, such as no beard, flattened throat nodes, developing breasts, undeveloped testicles or even atrophy, and no male sexual and reproductive functions; in the second case, when men who have reached puberty take estrogen, male secondary sex characteristics will gradually decline, showing a decrease in beard, delicate facial skin, change in voice, developing breasts, enlarged nipples, shrinking testicles, and a decline in male sexual functions, low libido, and virility. In this case, male secondary sexual characteristics gradually decline, showing a decrease in beard, delicate facial skin, change in voice, breast development, larger nipples, atrophy of testicles, decline in male sexual function, low libido, impotence, etc. Moreover, after taking estrogen, endocrine disorders, obesity, personality changes, affecting fertility, and in serious cases, causing tumors and other diseases.