Tamoxifen
About
About Tamoxifen
Tamoxifen is an FDA-approved SERM used in breast cancer treatment and prevention, applied off-label in men's health to treat gynecomastia, manage estrogen during TRT, and stimulate endogenous testosterone production post-cycle. In the context of hormone optimization, it blocks estrogen receptors in breast tissue and the hypothalamus-pituitary axis. It is one of the oldest and most studied SERMs available.
Science
Mechanism of Action
Acts as a competitive estrogen receptor antagonist in breast tissue and hypothalamus while exhibiting partial agonist effects in bone and uterine tissue; pituitary ER blockade increases LH/FSH secretion and downstream testosterone production in men.
Dosing
Typical Protocol
10–40 mg oral daily for gynecomastia; 20 mg daily for post-cycle testosterone recovery; duration 4–8 weeks.
⚠ Protocol information is for educational purposes only. Dosing must be determined by a licensed physician based on individual health status and goals.
Regulatory
Legal Status in 2026
This compound has completed clinical trials and received formal FDA approval for one or more indications. It can be legally prescribed by licensed physicians, filled at any licensed pharmacy, and may be covered by insurance. Off-label use by physicians is also legal. This is the highest level of regulatory clearance available in the US.
Evidence
Evidence Tier
Supported by the clinical trial data required for FDA approval, representing the highest evidence bar. Safety and efficacy have been established in multiple phases of human clinical trials.
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