Since most steroids aromatize to a greater or lesser extent, i.e. part of their active ingredient is converted into estrogens, male bodybuilders may experience a significant increase in estrogen levels. This can lead to growth of the mammary glands (gynecomastia) and an increased amount of fat. A first sign of a possible gynecomastia is slight pain when touching the nipples.
Antiestrogen Tamoxifen Citrate counteracts this by blocking the estrogen receptors of the affected body tissue and thus preventing a connection between estrogen and receptor. It is important to understand that Tamoxifen Citrate does not prevent aromatisation, but is exclusively an estrogen antagonist. This property has the disadvantage that a rebound effect can occur after weaning, i.e. the estrogen receptors suddenly released can absorb the estrogen accumulated in the blood.
It is also important to know that Tamoxifen Citrate has a tissue-specific effect, i.e. it is stronger in some tissues than in others. For example, it has a very strong effect in mammary gland tissue, but a very weak effect in fatty tissue. For this reason Tamoxifen Citrate is excellently suited for fighting gynecomastia, but can hardly do anything against the usual water and fat storage in the tissue.
In order to prevent gynecomastia, water and fat storage, aromatase inhibitors such as anastrozole (Arimidex) or exemestane (Aromasin) can be used to prevent the formation of estrogen from scratch.
However, this is not always desirable, especially when the athlete is primarily concerned with muscle building, as estrogens have an anabolic effect and inhibiting the formation of estrogen inhibits an important anabolic component in muscle building.