Tamoxifen

A dose-response trial in men taking bicalutamide for prostate cancer found fewer breast events with tamoxifen at 6 months (8.8% at the highest 20 mg dose vs 96.7% with placebo), without reducing PSA suppression. It does not establish that tamoxifen reliably treats every cause of gynecomastia or restores endocrine function after AAS use.^[1]

• Prevention of bicalutamide-associated events differs from established gynecomastia treatment and post-AAS recovery.
• Abstract-checked; full paper not confirmed open access as of 2026-09-09. A secondary citation lead (a 2001 Spanish-language review reporting tamoxifen use after AAS-associated gynecomastia, PMID 11715139) was identified via a 2023 plastic-surgery review but not independently retrieved or verified. No qualified clinical review.

In breast-cancer patients, tamoxifen coadministration lowered anastrozole plasma concentration by 27%. The combination offered no efficacy advantage over tamoxifen in the ATAC trial and that treatment arm was discontinued from the trial; ARIMIDEX labeling states that tamoxifen should not be administered with anastrozole.^[2]

• Postmenopausal breast-cancer population; no inference of a specific clinical outcome in men using these drugs after androgen exposure.
• Does not generalize to every SERM/aromatase-inhibitor pair.

Breast-cancer prevention trials found more thromboembolic events with individual SERMs including tamoxifen and raloxifene. Whether combining the two further increases that risk is unquantified.^[3]

• Trials in women; no dual-SERM trial and no evidence for a recovery regimen.

Testosterone-related hematocrit increases and tamoxifen/raloxifene thromboembolic findings come from different study populations. They motivate a possible overlapping concern, not evidence of a measured thrombosis increase from the selected pair.^[4][3]

• This evidence does not establish the magnitude or frequency of harm from the selected combination.