YK-11
A synthetic steroidal compound marketed as a SARM that is also claimed to inhibit myostatin. Human data are minimal and it is poorly characterized.
- Half-life
- 12 h
- Out of system
- ~2.5 days
- Route
- Oral
- Level
- Intermediate
Daily dosing holds steady levels. After the last dose, roughly 97% has cleared in ~2.5 days (five half-lives) — the window that matters for washouts, bloodwork and surgery.
What YK-11 is used for
- Marketed for rapid strength and muscle gains via claimed myostatin inhibition
- Cell studies suggest it can raise follistatin and drive muscle protein signaling
How it's typically used
Reported user ranges are roughly 5-10 mg daily, with no clinical basis.
What to watch for
- Being steroidal, it likely carries androgenic side effects and testosterone suppression
- Almost no human safety data exist, so effects and risks are largely unknown
- Not approved for human use; an unapproved research chemical banned in sport
About SARMs
- What they are
- Selective androgen receptor modulators — oral compounds designed to hit muscle and bone androgen receptors while sparing prostate and skin. None is an approved medicine anywhere.
- How they're run
- Taken orally once a day, typically in 8–12 week blocks.
- What to watch
- The "non-suppressive" reputation is marketing: most suppress natural testosterone, and several are liver-toxic. Independent testing repeatedly finds products containing something other than the label. Bloodwork before and after is the minimum.
Full guide
YK-11: A Tracking Guide for a Steroidal Myostatin-Claim Compound
A harm-reduction look at YK-11, a steroidal compound sold as a SARM with myostatin-inhibition claims, and why the human evidence is essentially absent.
Other sarms
Peptid AI is an educational and self-tracking tool — not a medical service, and not a vendor. Nothing here is medical advice, a prescription, or an endorsement. Doses reflect what is commonly reported in research literature; they are not recommendations. Many compounds listed are experimental, not approved for human use, and/or controlled substances that are illegal to possess without a prescription in many countries. Always consult a qualified physician before starting, changing, or stopping any protocol.