SERM vs AI, is selective estrogen receptor modulators vs aromatase inhibitors.
Both SERM and AI are used by bodybuilder to reduce and prevent estrogen-related adverse reactions in the AAS cycle.
Serms are estrogen receptor modulators, including tamoxifen and clomiphene.
AI is an aromatase inhibitor that includes exemestane and Arimidex.
AI is divided into two types, one is an irreversible steroid inhibitor, such as exemestane, which forms a permanent bond with the aromatase complex. Another nonsteroidal inhibitor, such as anastrozole and letrozole, inhibits aromatase through reversible competition.
The key difference between SERM vs AI is what they do to the body and how they affect estrogen. Serms work by blocking the effects of estrogen by binding to estrogen receptors in certain parts of the body. SERM acts on estrogen receptors, not estrogen itself, and does not reduce serum estrogen levels.
AI works by lowering estrogen levels in the body. AI prevents aromatase from converting testosterone into estrogen by blocking the action of aromatase in the body, thus reducing estrogen levels in the body, increasing testosterone levels and reducing the occurrence of male developmental disorders.
Simply put, SERM prevents estrogen from reaching certain parts of the body, while AI prevents the body from producing estrogen, and the two work in completely different ways.
SERM is very effective in controlling a large number of AAS-induced estrogen side effects. Serms like tamoxifen and Clomid help control gynecomastixia because they are designed to prevent the development of estrogen receptors in breast tissue. During PCT, SERM is generally chosen over AI, because PCT basically addresses the problem of endogenous testosterone inhibition.
AI is good for water retention, SERM is not. Therefore, bodybuilder will choose AI because of water retention issues. However, when bodybuilder is faced with gynecomastia, it will choose SERM.
SARMs do not aromatize, so using SARMs does not require AI.AAS do aromatize, so AAS cycle usually requires AI. However, some AAS that do not aromatize, such as DHT derivatives, do not require AI.