Anastrozole
Anastrozole is a potent, selective, reversible inhibitor of the aromatase enzyme (CYP19A1), which catalyzes the conversion of adrenal androgens (androstenedione and testosterone) to estrogens (estrone and estradiol) in peripheral tissues. In postmenopausal women, this substantially reduces circulating estrogen without affecting adrenal corticosteroid or aldosterone synthesis. In males, anastrozole reduces estradiol produced by peripheral aromatization of testosterone. Estrogen suppression at physiologically important levels can adversely affect bone mineral density and lipid profiles with prolonged use.
Injectable esters release over days to weeks depending on the ester; oral agents act within hours. Hormonal effects accrue over weeks, and dosing is individualized by a clinician.
Oral tablet; store at controlled room temperature (20-25 degrees C) in a dry place, protected from moisture.
Clinical Evidence
What the literature says
Pharmacokinetics
- Routes
- Oral
Citations (3)
Last reviewed: 2026-06-15
Research Guide
How users approach this compound
The following reflects patterns observed in research literature and community protocols. This is not medical advice and does not constitute a clinical recommendation.
Reported Uses
- FDA-approved adjuvant treatment of hormone receptor-positive early breast cancer in postmenopausal women
- FDA-approved treatment of advanced breast cancer in postmenopausal women
- Off-label: estradiol management in males receiving testosterone replacement therapy (prescriber-directed)
Key Research Benefits
- Potent suppression of estrogen biosynthesis via aromatase (CYP19A1) inhibition, as demonstrated in FDA-approved oncology indications
- Studied off-label in males to reduce estradiol elevation during androgen therapy
Potential Side Effects
Considerations and Cautions
- Premenopausal women (not appropriate; efficacy and safety not established)
- Pregnancy or breastfeeding
- Hypersensitivity to anastrozole or any component
- Concurrent use with tamoxifen or estrogen-containing medications (pharmacodynamic antagonism)
- Severe osteoporosis (relative; fracture risk consideration)
Labs to monitor
Educational context only, not a testing mandate. Any bloodwork decisions belong with your clinician.
- Estradiol (E2): Primary pharmacodynamic endpoint; overly suppressed E2 causes bone loss and joint symptoms.
- LH and FSH: Estrogen removal affects gonadotropin feedback; useful context in male use.
- Lipid panel: Estrogen suppression may adversely affect HDL and total cholesterol.
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Not medical advice
Information on DoseVault is for educational purposes only and is not a substitute for medical advice, diagnosis, or treatment from a qualified healthcare provider.