Letrozole: How It Works, What It's Studied For & Safety
Letrozole is a non-steroidal aromatase inhibitor that blocks androgen-to-estrogen conversion; FDA-approved for hormone-receptor-positive breast cancer in postmenopausal women. Clinicians consider it for adjuvant therapy for hormone-receptor-positive early breast cancer in postmenopausal women (FDA-approved). Compounded variants are dispensed by Wells Pharmacy Network only after a clinician evaluation.
Also known as: Femara
How does Letrozole work?
Letrozole reversibly binds the heme group of aromatase, blocking conversion of androgens to estrogens. It is more potent than anastrozole on a milligram basis and produces near-complete estradiol suppression in postmenopausal women.
What is Letrozole studied for?
- Adjuvant therapy for hormone-receptor-positive early breast cancer in postmenopausal women (FDA-approved)
- Off-label ovulation induction (often preferred over clomiphene in PCOS)
- Off-label estradiol management in male testosterone replacement
How is Letrozole taken?
FDA-approved as a 2.5-mg daily oral tablet. Compounded co-formulations exist for selected protocols.
Is Letrozole FDA-approved? Is it safe?
FDA-approved as a finished drug product when prescribed under its labeled indications. Compounded variants on this site are separate from the branded product and are dispensed only when a clinician determines a compounded preparation is appropriate. Long-term use is associated with reduced bone mineral density. Estradiol monitoring is essential during off-label TRT-adjunct use. Compounded prescription-only preparations are dispensed by Wells Pharmacy Network. Eligibility is decided by a licensed clinician based on intake and labs, not by checkout. Compounded products on this site are not FDA-approved and are not generic equivalents of any branded medication.
In the Regen Therapy catalog
This compound does not currently appear in an active Regen Therapy protocol. Browse the full catalog for adjacent options.
What does the research say about Letrozole?
BIG 1-98 trial in adjuvant breast cancer; PPCOS II trial supported off-label ovulation induction in PCOS.
Citations & further reading
Considering Letrozole as part of a protocol?
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