This page is reference information only. Most compounds described here are research chemicals, not FDA-approved medications. MyTRT does not sell, recommend, or endorse the use of these substances. Always consult a qualified physician.
Letrozole (Femara)
Aromatase Inhibitor (AI)
/WHAT_IT_IS
Letrozole is a third‑generation non‑steroidal aromatase inhibitor that blocks the conversion of androgens into estrogen, dramatically reducing estrogen levels.
/USAGE
Warmly utilized in breast cancer (HR+ post‑menopausal) treatment, ovulation induction in women, and off‑label in men for estrogen control, fertility enhancement, and testosterone optimization.
/MECHANISM_OF_ACTION
Reversibly binds to and competitively inhibits the aromatase (CYP19A1) enzyme, preventing conversion of testosterone and androstenedione into estradiol and estrone.:contentReference[oaicite:1]{index=1}
Reported Benefits
- +Reduces estrogen by ~98%
- +Normalizes testosterone in obese men
- +Enhances sperm parameters and fertility
- +Effective for ovulation induction
Reported Side Effects
- −Hot flashes, sweating, dizziness, headache
- −Joint, bone, or muscle pain
- −Fatigue, weakness
- −Weight gain and swelling
- −Hair loss
- −Cholesterol elevation
- −Bone mineral density reduction (long-term)
- −Rare: liver enzyme changes, neutropenia, interstitial lung issues, QT prolongation
/STACKED_WITH
/RESEARCH_NOTES
Low‑dose weekly dosing (2.5 mg) normalizes testosterone in hypogonadal obese men, though free testosterone may become supraphysiological:contentReference[oaicite:3]{index=3}. Also used in infertile men to improve sperm count and quality:contentReference[oaicite:4]{index=4}. In women, used off‑label for ovulation induction with favorable live‑birth outcomes:contentReference[oaicite:5]{index=5}.
/REFERENCE
https://pubmed.ncbi.nlm.nih.gov/18426834/Browse all 89 in the app.
MyTRT's in-app library has the same 89 peptide entries plus dosing notes, stack builders, and the ability to log them alongside your TRT protocol.