Independent reference & toolkit 100 compounds graded · Last reviewed June 2026

Compare · Aromatase inhibitor

Anastrozole vs Exemestane

Both are aromatase inhibitor compounds. Here's how they line up on the evidence — graded the same way.

AnastrozoleExemestane
Evidence 10/10 10/10
ClassAromatase inhibitorAromatase inhibitor
SummaryAnastrozole is a non-steroidal aromatase inhibitor — a prescription breast-cancer drug, not a peptide — with strong trial evidence in postmenopausal women and a separate, unstudied off-label use by men to suppress estrogen. It is banned in sport at all times.Exemestane is an oral, steroidal third-generation aromatase inhibitor — an FDA-approved breast-cancer drug, not a peptide. Bodybuilders use it off-label to suppress estrogen, an unapproved and unstudied practice that is banned in sport (WADA S4) and can be genuinely harmful when estrogen is crashed.
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Anastrozole

Anastrozole, sold as Arimidex, is a non-steroidal aromatase inhibitor: a prescription breast-cancer drug that lowers the body's estrogen by blocking the enzyme that makes it. It helps to be clear about what anastrozole is and isn't. It is not an anabolic-androgenic steroid (a muscle-building…

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Exemestane

Exemestane, sold as Aromasin, is a pill you swallow that lowers the body's estrogen. It is a steroidal third-generation aromatase inhibitor (AI) — a real, well-studied cancer drug. It is worth being clear about what it is and isn't: exemestane is not a peptide, not a SERM (selective estrogen…

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