Estrogen is the main female sex hormone. It is what helps in the development and maintenance of female sex characteristics. Estrogen though a female sex hormone, is also present in men in low quantities.
Estrogen becomes harmful for a bodybuilder when their bodies produce higher quantities of estrogen as compared to testosterone. As men get older their bodies naturally decrease testosterone production, which is replaced by estrogen.
A high quantity of estrogen in older men is responsible for their balding, huge tummies and moobs (male boobs). Estrogen blockers have come up to fight this issue of increasing estrogen production in the male body.
Estrogen blockers are also recommended to men who wish to have children as they fight infertility and low sperm count. They are also incredibly efficient in restoring the hormonal balance in men.
Estrogen-blocking supplements help in boosting testosterone levels in both men and women which result in increased protein synthesis, muscle mass, strength, healing, regeneration and repair and fat loss among many other benefits.