SARMs

YK-11: Complete Research Guide

YK-11 is a synthetic steroidal compound studied as a partial androgen receptor agonist with additional reported activity as a myostatin inhibitor, making its proposed mechanism distinct from the nonsteroidal SARMs it is…

📖 5 min read 🗓️ Updated August 2026 ✍️ Compound X Research Team 🇺🇸 US, UK, CA & AU Sourcing
YK-11 research guide cover

🔬 Studied for: Myostatin-Pathway Research

💊 Also studied for: Steroidal-SARM Research

🧪 Not FDA-approved — sold strictly for laboratory research

📈 No standardized human dosage established in published literature

What Is YK-11?

YK-11 is a synthetic steroidal compound studied as a partial androgen receptor agonist with additional reported activity as a myostatin inhibitor, making its proposed mechanism distinct from the nonsteroidal SARMs it is often grouped with commercially.

Mechanism of Action

YK-11 is studied for activating the androgen receptor while also increasing expression of follistatin, a protein that inhibits myostatin — a negative regulator of muscle growth — giving YK-11 a proposed dual mechanism distinct from receptor-selective SARMs alone.

Studied Benefits

These are effects YK-11 has been studied for in available preclinical and early research — not claims about guaranteed outcomes.

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Myostatin-Pathway Research

In-vitro studies have investigated YK-11's effect on follistatin expression and myostatin inhibition in muscle cell cultures, which is the basis for research-community interest in it as a potentially more potent anabolic signal than androgen receptor activation alone.

Steroidal-SARM Research

Because YK-11 is structurally a steroid rather than the nonsteroidal chemotype of most SARMs, it is sometimes studied separately as a distinct structural class within androgen receptor modulator research.

Dosing Guide

What the research shows

No dosage of any kind has been clinically validated for YK-11 in humans or animals in vivo. Any protocols circulating in research-community sources are not supported by peer-reviewed in-vivo or clinical trial data.

Compound X does not provide dosing recommendations. YK-11 is sold for laboratory research use only and is not intended for human consumption.

Reported Side Effects

YK-11's published research is limited almost entirely to in-vitro (cell culture) studies rather than animal or human trials. It has no established human safety data, has never been evaluated in human clinical trials, and is not FDA-approved.

FAQ

Is YK-11 FDA-approved?

No. YK-11 is not FDA-approved for any indication and is sold strictly as a research chemical, not a medication or dietary supplement.

What is YK-11 commonly studied for?

Myostatin-Pathway Research — In-vitro studies have investigated YK-11's effect on follistatin expression and myostatin inhibition in muscle cell cultures, which is the basis for research-community interest in it as a potentially more potent anabolic signal than androgen receptor activation alone.

Is YK-11 legal to buy in the US?

In the US, UK, Canada and Australia, YK-11 is generally sold labeled "for research use only, not for human consumption." It is not approved as a dietary supplement or medication in any of these countries.

References

YK-11 in-vitro research is indexed on PubMed under search terms such as "YK11 myostatin follistatin androgen receptor."

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