What is YK-11?
YK-11 is a steroidal compound that acts as both a partial androgen receptor agonist and a myostatin inhibitor. Unlike traditional SARMs which are non-steroidal, YK-11's chemical structure is derived from DHT (dihydrotestosterone), making it a unique hybrid compound in research literature.
It was first described by Japanese researcher Yuichiro Kanno in 2011. Research interest centres primarily on its ability to inhibit myostatin (GDF-8), a protein that limits muscle growth, while also exhibiting anabolic activity via androgen receptor partial agonism. For research purposes only.
⚠ Research Purposes Only: YK-11 is a research chemical with no approved human use. It is not approved by the FDA or MHRA. Human data is extremely limited and preclinical in nature.
YK-11 Research Profile
| Parameter | Research Data |
|---|---|
| Compound Class | Steroidal SARM / Myostatin Inhibitor |
| Mechanism | Partial AR agonist + myostatin inhibitor |
| Half-Life | ~6–10 hours (estimated, limited data) |
| Research Area | Muscle cell differentiation, anabolism |
| Androgenic Activity | Partial (less than testosterone) |
| Suppression | Expected (steroidal structure) |
The Myostatin Angle
Myostatin (GDF-8) is a protein that acts as a biological brake on muscle growth. Individuals with naturally lower myostatin levels — or animals with myostatin gene knockouts — display dramatically increased muscle mass. YK-11 research suggests it may inhibit myostatin signalling in muscle cells, potentially removing this ceiling on muscle protein synthesis.
In vitro research published by Kanno (2011) demonstrated that YK-11 increased follistatin levels — a myostatin antagonist — in C2C12 myoblasts more than DHT alone at equivalent concentrations. However, in vivo human data confirming these effects remains absent.
Suppression Considerations
Given YK-11's steroidal structure, researchers studying extended protocols typically include HPTA suppression monitoring. Unlike non-steroidal SARMs, the DHT-derived backbone may produce stronger androgenic side effects in research models. Post-cycle research compounds such as Enclomiphene are often studied alongside it.
Hepatotoxicity Research
Preliminary in vitro data suggests YK-11 may exhibit hepatotoxic properties at higher concentrations. Research protocols studying this compound should include hepatic biomarker monitoring. TUDCA is commonly researched alongside hepatically active compounds.
🔬 Where to Source YK-11 for Research (USA & UK)
For USA and UK researchers, BehemothLabz stocks YK-11 with third-party certificates of analysis. All products are for research purposes only and not approved for human consumption.
Visit BehemothLabz →⚠ Affiliate link — use code Tomjunkie for 20% off. Research purposes only.
Frequently Asked Questions
YK-11 is often categorised as a SARM but it is technically a steroidal compound derived from DHT. Unlike most SARMs which are non-steroidal, YK-11 acts as a partial androgen receptor agonist and myostatin inhibitor.
YK-11 uniquely inhibits myostatin, a protein that limits muscle growth. This dual mechanism — AR partial agonism plus myostatin inhibition — sets it apart from non-steroidal SARMs like RAD-140 or Ostarine. For research purposes only.
Yes — because of its steroidal structure, YK-11 is expected to cause HPTA suppression. Research protocols studying it typically include post-cycle support compounds. For research purposes only.
BehemothLabz is a widely used vendor for YK-11 with HPLC certificates of analysis available. All products are for research purposes only.