What Is YK-11?
YK-11 is an experimental synthetic steroidal compound that is widely discussed online as both a selective androgen receptor modulator and a myostatin-pathway modulator. Popular descriptions commonly attribute its discovery or synthesis to Japanese researcher Yuichiro Kanno in 2011 and identify it as a derivative or analogue of dihydrotestosterone (DHT). The compound is structurally different from the non-steroidal SARMs that dominate pharmaceutical research. It is often marketed as unusually potent because it is proposed to combine androgen-receptor signaling with increased follistatin expression and consequent reduction of myostatin signaling. Those descriptions are based mainly on preclinical findings, secondary reporting, and commercial claims rather than on adequately controlled human trials.
YK-11 is sometimes described as a partial androgen-receptor agonist, although the available public evidence is too limited to define its receptor pharmacology, tissue selectivity, dose-response relationship, oral bioavailability, metabolism, or clinical potency with confidence. A frequently repeated estimate places its half-life at approximately 6–10 hours, but this figure is not supported by a robust, publicly established human pharmacokinetic study and should not be treated as a validated parameter. The compound has no approved therapeutic indication, no established safe human dose, and no reliable evidence that it produces a clinically meaningful or safe reduction in myostatin activity. Because it may affect androgen signaling and because its long-term effects are unknown, it should be regarded as an advanced research compound rather than a supplement or a proven performance-enhancing medicine.
Quick Reference
Member reference tables summarize the compound's research parameters.
Research Indications
Research Protocols
As reported in cited literature and research-community logs (see Research Citations below), not a personal dosing recommendation.
This member section describes parameters reported in the research literature.
Peptide Interactions
This member section summarizes reported compound interactions and evidence limitations.
Reported Research Time Points
This member section summarizes reported research time points.
Safety Notes
Included for harm-reduction awareness only, in the event this compound is encountered outside its labeled research use. Inclusion here does not imply RUO Codes endorses, recommends, or instructs human use.
This member section discusses research safety considerations and uncertainties.
Quality Indicators
Research Citations
- Selective androgen receptor modulator, YK11, regulates myogenic differentiation of C2C12 myoblasts by follistatin expression.
Kanno, Y., Hikosaka, K., Iqbal, J., et al., 2011, Biological & Pharmaceutical Bulletin - The safety, pharmacokinetics, and effects of LGD-4033, a novel nonsteroidal oral selective androgen receptor modulator, in healthy young men.
Basaria, S., Jasuja, R., Huang, G., et al., 2013, The Journals of Gerontology: Series A - The selective androgen receptor modulator GTx-024 (enobosarm) improves lean body mass and physical function in healthy elderly men and postmenopausal women: results of a double-blind, placebo-controlled phase II trial.
Dalton, J. T., Barnette, K. G., Bohl, C. E., et al., 2011, Journal of Cachexia, Sarcopenia and Muscle - The effects of supraphysiologic doses of testosterone on muscle size and strength in normal men.
Bhasin, S., Storer, T. W., Berman, N., et al., 1996, New England Journal of Medicine