YK-11 (YK-11 (Myostatin Inhibitor / SARM))
A synthetic steroidal compound classified as both a SARM and a myostatin inhibitor. Combines AR partial agonism with follistatin induction.
How it works
Partial androgen receptor agonist that induces follistatin expression, creating dual myostatin inhibition and AR activation.
Key facts
- Molecular weight: 430.54 Da
- Half-life: ~6-10 hours
- Bioavailability: ~70% oral
- Storage: Room temperature, protect from light.
Dosing overview
- Typical dose: 5-10 mg
- Frequency: Once daily
- Duration: 6-8 weeks
- Route: Oral
Reported benefits
- Dual anabolic mechanism
- Follistatin induction
- Oral convenience
- Muscle hardening
Possible side effects
- Liver stress potential
- Testosterone suppression
- Joint dryness
- Hair shedding risk
Research
- YK-11 follistatin induction in myocytes (2018): Increased follistatin expression 4-5x in C2C12 cells, exceeding effects of DHT.
- Selective AR modulation by YK-11 (2019): Tissue-selective anabolic activity with minimal androgenic effects on prostate.
Community reviews of YK-11
- dose_diary_alex rated it 5/5 - Genuinely effective after 3 months: Been using YK-11 for about 3 months and the results are clear. Not overnight dramatic, but a steady, consistent improvement that became undeniable by the end of the first month. The mechanism makes sense based on what I have read in the literature, and my subjective experience matches the expected timeline. Benefits built gradually and plateaued at a good level. Side effects were minimal to none at the dose I used. Followed proper protocols for sourcing, storage, and administration. Would recommend to others who have done their research and have realistic expectations.
- protocol_planner rated it 4/5 - Worth adding to the protocol: YK-11 has been a worthwhile addition. I am data-driven and tracked relevant markers before, during, and after. The improvement is measurable and correlates with the intervention timeline. What sets this apart from some compounds I have tried is the consistency. Benefits did not fluctuate wildly or disappear. They built up and maintained. That gives me confidence in the mechanism. Tolerance has been excellent. Nothing in my bloodwork or subjective experience raised any flags. This is the kind of compound that does its job quietly without causing problems. Exactly what you want.
- steady_hand_jen rated it 5/5 - Noticed clear benefits within weeks: Added YK-11 to my protocol about 1 month ago and it has earned its place. The benefits became noticeable around week 2-3 and have been consistent since. What I appreciate about this compound is the predictability. It does what the research suggests it should do, at roughly the timeline you would expect. No surprises, no dramatic swings, just steady improvement. No notable side effects to report at my dose. Sourcing is always the challenge with research compounds, insist on third-party testing. Storage and reconstitution per standard protocols. Plan to continue.
- formernico rated it 5/5 - Skeptical at first, but YK-11 changed my training: I went into YK-11 pretty skeptical, since a lot of these things talk big and do not do much. For me, that skepticism faded in about 4 weeks. My lifts moved up, muscles felt harder, and recovery seemed better after long clinic days and training in the humid South.
- optimizer920 rated it 4/5 - Leaner look, but I still liked RAD more: I ran YK-11 for about 8 weeks while I was deep into ultrarunning and trying to keep some muscle in the middle of high mileage. For me it did seem to give that harder, denser look, and my legs felt a bit more solid in training. I liked it, but I preferred RAD for overall size and strength. YK felt a bit sharper, just less complete for my goal. Could be just my experience, na.
- recovery_renee rated it 5/5 - Dense, harder muscle in about 6 weeks: For me, the biggest change was how much harder and denser I looked by week 6, especially through my shoulders and upper back. I’m a pharmacist on the East Coast, lifting after long shifts, and that visual tightening was exactly what I was chasing. Could be my own response, but I loved it.
Compare YK-11
Research and educational reference only. Not medical advice.