YK-11
preclinical onlyWADA bannedNot FDA approvedResearch only
Published Dose Range
Low5 mg/day
Typical5-10 mg/day
High15 mg/day
Marketed as a SARM but classified as a steroidal myostatin modulator in the literature. No published human trials — dosing is anecdotal.
Published Cycle Range
Short4 wks
Typical6 wks
Long8 wks
Short cycles recommended due to hepatotoxicity concerns and lack of human safety data.
Off-cycle: 8 weeks
Administration
Routesoral
FrequencyTwice daily
Preferred timingSplit AM/PM
Short half-life ~6 hours — usually split into 2 doses.
Safety Profile
Contraindications
- • Liver disease
- • Cardiovascular disease
- • Pregnancy
Common side effects
- • HPG axis suppression
- • Hair shedding
- • Aggression
Serious risks
- • Hepatotoxicity — steroidal structure, higher liver stress than non-steroidal SARMs
- • Tendon issues reported anecdotally
- • Long-term safety completely unknown — no human trials
Drug interactions
- • Avoid with hepatotoxic compounds
Requires monitoring
- • Liver function
- • Testosterone
- • Creatine kinase
Pregnancy / breastfeeding
Contraindicated
Sex-Specific Notes
Male
Strong suppression expected
Female
Not recommended — no female data and virilization risk
Common Misconceptions
- Often mislabeled as "non-suppressive myostatin inhibitor" — HPG suppression is documented
- Steroidal structure — closer to a designer steroid than a non-steroidal SARM
Next Steps
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