What is Tamoxifen?
Tamoxifen blocks estrogen receptors in breast tissue and is a standard drug for treating and preventing recurrence of hormone-sensitive breast cancer. In the hypothalamus it acts similarly to clomiphene and can raise LH and testosterone. In the bodybuilding scene it is used without a medical indication against steroid-induced breast enlargement (gynecomastia) and as a "PCT" agent.
How well studied is Tamoxifen?
Very well studied: large randomised trials and decades of use in breast cancer. There are no registration trials for use after steroid use, only observational data.
What side effects and risks does Tamoxifen have?
Boxed warning: increased risk of uterine cancer, stroke and pulmonary embolism/blood clots, sometimes fatal. Also visual problems and cataracts, liver changes and interactions with other medicines. In men, use without medical supervision is particularly problematic because of the thrombosis risk.
Is Tamoxifen approved in Germany?
In short: yes. Approved in the EU/Germany and prescription-only. WADA: S4.2 (anti-estrogenic substances) – prohibited at all times. Possession and trafficking for doping purposes can fall under the German Anti-Doping Act (AntiDopG); black-market products are frequently counterfeit.
Sources
Note: We deliberately do not list any doses here. For approved medicines, your doctor sets the dose; for unapproved substances there is no reliable information.