Explore YK-11 dosage trends, reconstitution volumes, and vial size patterns from anonymized WPA peptide calculator data.
YK-11 is a steroid-derived compound sold as a SARM and marketed as a 'myostatin inhibitor' — not a peptide. It is sold as a research chemical (capsules or an oral liquid) with no human trial data.
In cultured C2C12 myoblasts, YK-11 binds the androgen receptor as a partial agonist and increases secretion of follistatin — a protein that binds and neutralises myostatin, the principal endogenous negative regulator of muscle growth.[1][4] The follistatin-induction mechanism is what underpins the consumer "myostatin inhibitor" framing. **The follistatin-induction effect has been demonstrated in cultured cells, not in humans, and the magnitude and durability of any in-vivo human effect on circulating follistatin or myostatin is not characterised.** Because YK-11 retains the 17α-substituted steroidal scaffold, it shares some structural features with classical 17α-alkylated oral anabolic steroids, which raises the question of whether it carries hepatic-toxicity liabilities of that class.
The Kanno 2011 paper is the founding pharmacology characterisation of YK-11 and remains the most-cited primary source.[1] Subsequent in-vitro work has explored YK-11's AR-agonism profile and the follistatin/myostatin signalling effect in muscle cell lines.[4][5] There is no published human pharmacokinetic study, no Phase 1 trial, no registered clinical development program, and no peer-reviewed human safety or efficacy data.[2] Consumer-use case reports have begun to appear in the broader SARM-related drug-induced liver injury literature.[6]
Not FDA-approved. No registered clinical trial. In-vitro pre-clinical data only. WADA-prohibited at all times. Research-grade material only.
YK-11 has a reported half-life of ~6–10 hours (estimate). The pharmacokinetic reference models an interval of once or twice daily; this is not a measured community cadence or a dosing recommendation. An estimated half-life of several hours means twice-daily dosing keeps levels reasonably steady. No formal human pharmacokinetic data exist for this compound. Pharmacokinetic source: No published PK; estimate for this myostatin-inhibiting SARM. It is catalogued under Other Peptides on WPA.
6 YK-11 reconstitution calculations have been logged by the WPA community.
This is the lifetime header population. Each chart and its associated analysis below use their own selected period and denominator; frequency responses are a separate cohort.
These figures come from anonymized WPA peptide calculator sessions, not verified administrations or unique people. Separate modal inputs do not establish a joint protocol. They are community input statistics — not dosing recommendations, and not medical advice.
These figures come from anonymized WPA peptide calculator sessions.
All figures shown are aggregated from anonymized calculator inputs and are provided strictly for independent laboratory research and educational purposes. They are community usage statistics — not dosing recommendations, and not medical advice.