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
Osilodrostat is covered by S1.2 of the effective 2026 WADA List and is prohibited in and out of competition. The S1.2 examples do not exhaust the category. [3]
S1.2; 2026 List, printed pages 5–6 · 2026 rules apply from 1 January 2026. Any 2027 material below concerns future rules from 1 January 2027; it is not current clearance.
Medical context and mechanism
EMA describes osilodrostat in Isturisa for adults with Cushing’s syndrome. It inhibits 11-beta-hydroxylase, reducing cortisol production. Its placement in S1.2 should not be mistaken for proof that it acts as a conventional androgen-receptor agonist. [1]
Human evidence and health risks
EMA’s main-study account includes 137 initially treated patients, followed by a randomized withdrawal phase in selected responders. Continued treatment maintained cortisol control more often than placebo. Adrenal insufficiency is a key risk, alongside symptoms such as nausea, fatigue and vomiting. [1]
- The withdrawal comparison applies to selected responders, not all enrolled patients. Treatment requires specialist monitoring; no regimen is recommended here.
List year
The 2026 List is the effective edition on this review date. The checked 2027 S1 text showed no change, but the 2027 edition does not take effect until 1 January 2027. [3] [4] [2]
- Consult the official edition and responsible anti-doping organization for consequential decisions. This reference does not provide medical advice, a TUE decision, product certification or individual clearance.
What remains uncertain
- This is a targeted source check, not a systematic review or independent clinical/regulatory sign-off. Uncited draft claims remain unpublished.
- Chemical registry identifiers, every alias and jurisdiction-specific product availability have not been exhaustively reconciled.
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.
- Isturisa EPAR ↗Accessed 2026-11-10 · relevant primary-source text read
Overview, mechanism, study design and risks
- 2027 Prohibited List resource page ↗Accessed 2026-11-10 · relevant primary-source text read · FUTURE 2027 SOURCE
Resource description and effective date
- WADA 2026 Prohibited List ↗Accessed 2026-11-10 · relevant primary-source text read
Introduction and S1, printed pages 3, 5–6
- WADA 2027 Prohibited List, currently linked English file ↗Accessed 2026-11-10 · relevant primary-source text read · FUTURE 2027 SOURCE
Cover and S1, printed pages 1, 5–6
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.