Checked 2026-11-10. Independent clinical review has not been completed. WADAFUK is independent of WADA and does not provide medical advice or an individual anti-doping determination.
Prohibited at all times
2026 S4.1: prohibited at all times. Specified. [1]
S4.1 · 2026 rules apply from 1 January 2026. Any 2027 material below concerns future rules from 1 January 2027; it is not current clearance.
Historical clinical evidence
An 18-patient pilot study investigated formestane in postmenopausal women with locally advanced or metastatic breast cancer. Some evaluable patients responded or had stable disease; reported adverse effects included hot flushes, lethargy and muscle pain. [2]
- Abstract only; small uncontrolled pilot. The authors’ tolerability conclusion is not a general safety assurance.
What remains uncertain
- Current country-specific authorization, original formulation/route label and complete safety warnings were not verified; historical research does not establish current supply.
Check the sources.
These are concise editorial paraphrases of selected sources, not a systematic review or a reproduction of source tables. Access depth is shown for each reference; an abstract-only check cannot resolve details found only in a full paper.
- WADA 2026 Prohibited List ↗Accessed 2026-11-10 · Relevant official full-text sections opened
Printed pp. 3, 9–12: introduction, S3, S4 and S5 as applicable
- Formestane pilot clinical trial ↗Accessed 2026-11-10 · Primary-study abstract and metadata
Abstract and bibliographic record
Check the current official WADA List and the relevant anti-doping authority for your sport, product, route and circumstances. Do not stop or change necessary treatment based on this page. Ask a qualified clinician about health decisions. Missing evidence does not establish safety.