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Approved (oncology) / off-label (male) — clinician-directed. For ER-positive breast cancer the standard adjuvant dose is 20 mg once daily for 5-10 years. For off-label male gynecomastia, the randomized trials used roughly 10-20 mg daily (10 mg/day prophylactically alongside an antiandrogen, 20 mg/day to treat established gynecomastia). For idiopathic male infertility, the trials typically used 20 mg/day. Bodybuilding 'post-cycle therapy' commonly uses 10-40 mg/day tapered — a use with no controlled-trial evidence. There is no FDA-approved male dose.

Any time

Tamoxifen citrate tablets (approved for breast cancer; off-label in men)

Prescription-only and clinician-directed — this is a controlled substance, NOT a self-administered supplement, and we do not provide a non-medical dosing protocol. For context only: TRT for diagnosed hypogonadism is titrated to a mid-normal testosterone level. Intramuscular testosterone esters (cypionate/enanthate) are commonly dosed around 50–100 mg weekly (or ~100–200 mg every 2 weeks); long-acting testosterone undecanoate is dosed less frequently. Transdermal gels (~50–100 mg/day applied) and subcutaneous injection are alternative routes. Supraphysiologic anabolic-steroid doses are far higher, illegal, and dangerous — not a regimen this library endorses.

Any time

Clinician-prescribed testosterone (intramuscular ester or transdermal gel) for diagnosed hypogonadism — controlled substance, prescription-only

• History of venous thromboembolism (deep-vein thrombosis or pulmonary embolism) or stroke — tamoxifen raises clot risk
• Concurrent warfarin / anticoagulant therapy in the prevention setting (per label)
• Pregnancy and breastfeeding (can harm the fetus)

• Warfarin / anticoagulants
• Strong CYP2D6 inhibitors (e.g. paroxetine, fluoxetine, bupropion)
• Aromatase inhibitors / other SERMs / exogenous estrogens

• Use without a prescription / without medical supervision — testosterone is a Schedule III controlled substance and prescription-only
• Active prostate cancer or active breast cancer in men
• Untreated severe erythrocytosis / hematocrit above the safe threshold

• Anticoagulants / warfarin
• Other anabolic steroids / SARMs / hCG / aromatase inhibitors
• Insulin / glucose-lowering drugs