Estrogen injections are generally not allowed for men. Estrogen is secreted by the ovaries of women, which can promote the maturation of female accessory sex organs and the emergence of secondary sexual characteristics, and has a certain role in maintaining normal libido and reproductive function, which is very important for women, and also has a certain role in some other systems, too. The hormones in male body are mainly androgens, if injected estrogen will cause some changes to the body, and feminization may occur, which is mainly manifested as thinning of voice. In addition, the hair on the body parts will be reduced, and the beard will degenerate, and in serious cases, the development of mammary glands as well as the shrinkage of testicles will occur, which will also have certain effects on the sexual function and libido. Men who are not feeling well are advised to go to the hospital in time for examination and treatment, and not to blindly inject estrogen by themselves to avoid some adverse effects on the body.