YK-11
Aliases: YK11
Last verified: 2026-09-23
The short version
An atypical "SARM" — steroidal structure, partial AR agonist that reportedly raises follistatin (indirect myostatin inhibition). Popular but least researched. Key fact: No controlled human trials exist. Everything known about YK-11 in humans comes from indirect sources and self-reports. Status: preclinical. Not approved; WADA-banned (S1).
Identity & type
- Molecular type
- SARM
- Origin
- An atypical "SARM" — steroidal structure, partial AR agonist that reportedly raises follistatin (indirect myostatin inhibition).
Mechanism of action
Partial AR agonism + follistatin induction in muscle cells (in vitro).
not confirmed in humans
Dosing & routes
Official / clinical context
No approved official document exists for YK-11. Any protocols mentioned are to be read as information, not as a recommendation.
Regulator-approved labeling and published study designs — never a recommendation.
Community-reported practice
Community: 5–10 mg/day. Rapid fullness and "hardness" are reported, but data are the thinnest of all SARMs; some report joint pain at higher doses.
Unverified self-reports. Not medical advice. Not endorsement.
Expected effects (community)
Rapid fullness and "hardness" are reported, but data are the thinnest of all SARMs; some report joint pain at higher doses.
Protocol — official vs community
Official / label
No official protocol exists — this compound has no approved product.
Community (anecdotal)
5–10 mg oral daily; some experienced listings go to 15 mg.
- Cycle:
- 6–8 weeks.
- Break:
- 4+ weeks with PCT, particularly when stacked with suppressive SARMs.
Almost always run as part of a stack rather than solo — typically alongside LGD-4033 or RAD-140, framed as a 'myostatin-inhibition layer'. The follistatin mechanism is in-vitro only, and joint pain is the most reported complaint at higher doses.
Human evidence
No controlled human trials exist. Everything known about YK-11 in humans comes from indirect sources and self-reports.
Preclinical evidence
Cell studies only; no high-quality animal publications.
Known risks
- Systemically unknown; potential hepatotoxicity, suppression.characterized
- WADA prohibition (S1 anabolic agents)characterized
Teal: characterized in clinical/labeling contexts. Amber: theoretical or reported outside controlled settings.
Unknowns & evidence gaps
- All human pharmacokinetics, safety and efficacy
Frequently asked questions
References
Systematic references are being expanded; verify sources directly before any decision.