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SARM / Myostatin-Related

YK-11

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Overview

A steroidal compound claimed to act as a SARM and to raise follistatin (a myostatin inhibitor) in cell studies; there is no meaningful human evidence.

How it works

YK-11 is an unusual entry: it has a steroidal structure and is marketed as a SARM, but it's also claimed to work as a myostatin inhibitor.

The dual claim is that it both partially activates the androgen receptor and, based on cell studies, raises follistatin — a protein that blocks myostatin, the body's natural 'brake' on muscle growth. Releasing that brake is the theoretical basis for the muscle-growth hype.

This rests almost entirely on in-vitro work; there's essentially no human data. Its steroidal structure also raises liver and hormonal concerns, and it is not approved.

Mechanism · Detailed Analysis
Molecular targetA gestrinone-derived steroidal partial AR agonist; in vitro reported to raise follistatin.
Proposed downstream effectsAR signalling plus proposed follistatin-mediated antagonism of myostatin/GDF-8.
Evidence & caveatsEssentially no human data; its steroidal structure raises hepatic and hormonal concerns. Not approved.
Published EvidenceLoading cited studies from PubMed…
Human Data ···

Searching the published record…

Animal ···

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In Vitro ···

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Educational aggregation of public literature. Not medical advice and not a recommendation to use any compound. Many compounds here are not approved for human use. Consult a licensed clinician.