Compare · Aromatase inhibitor
Exemestane vs Letrozole
Both are aromatase inhibitor compounds. Here's how they line up on the evidence — graded the same way.
| Exemestane | Letrozole | |
|---|---|---|
| Evidence | Strong human | Strong human |
| Class | Aromatase inhibitor | Aromatase inhibitor |
| Summary | 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. | Letrozole is an oral, nonsteroidal third-generation aromatase inhibitor — an FDA-approved breast-cancer and (off-label) fertility 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. |
| Full profile → | Full profile → |
Exemestane
Exemestane, sold as Aromasin, is an oral, steroidal third-generation aromatase inhibitor (AI) — a legitimate, well-studied oncology drug. It is important to be precise about what it is: exemestane is not a peptide, not a SERM (selective estrogen receptor modulator like tamoxifen), and not an…
Letrozole
Letrozole, sold as Femara, is an oral, nonsteroidal third-generation aromatase inhibitor (AI) — a legitimate, well-studied drug with a strong evidence base in both oncology and fertility medicine. It is important to be precise about what it is: letrozole is not a peptide, not a SERM (selective…