SARMs & Related Compounds
YK-11
myostatin inhibitor · steroidal SARM
What it is
YK-11 is technically not a true SARM — it's a steroidal compound derived from DHT that's marketed as a SARM. Its main claim to fame is being a myostatin inhibitor. Myostatin is the body's natural brake on muscle growth; blocking it removes the cap.
How it works
Two mechanisms: (1) partial androgen receptor agonism (the "SARM-like" activity), and (2) inhibition of myostatin via follistatin upregulation. The myostatin inhibition is what gives YK-11 its reputation for "uncapped" muscle growth.
Benefits
- Significant muscle gains via myostatin inhibition
- Hardness/density (not water weight)
- Strength gains
Timeline
- Week 1–2
- Strength gains begin.
- Week 4–6
- Hard, dense muscle gains.
- Week 6–8
- End of cycle; PCT required.
Dosing & titration
Standard dose5–10 mg orally daily
Cycle length6–8 weeks ON, 8–12 weeks OFF
When to titrate upLiver toxicity rises with dose. Most users stay at 5–10 mg.
Side effects & risks
- Liver toxicity (hepatotoxic — methylated structure)
- Testosterone suppression
- HDL reduction
- Joint dryness
- Headaches
Liver toxic. Use liver support supplements during cycle (TUDCA, NAC). Get baseline and post-cycle liver enzymes. Do NOT stack with other liver-toxic compounds. Banned in sports.
Typical price
$60–$120/moFrom research suppliers.
Studies
- Kanno Y et al. The discovery of a new class of androgen receptor partial agonists — YK-11's mechanism. PubMedEndocrinology, 2011
- Search PubMed for YK-11 — PubMed searchLive PubMed search
Educational reference only. Not medical advice. Not FDA-approved.