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SARMs

YK-11: a steroidal compound sold as a SARM, with no human data

Compound: YK-11Evidence base: Preclinical onlyUpdated: 2026-09-05Last reviewed: September 2026By: APEDRA editorial team

YK-11 is a steroidal androgen receptor ligand studied only in cell culture and marketed on a myostatin-inhibition claim. No human pharmacokinetic, dosing or safety study of any kind has been published.

Key points

  • Evidence is limited to in-vitro work in muscle cell lines; there is no animal safety programme and no human trial.
  • It is structurally steroidal, so grouping it with non-steroidal SARMs is misleading.
  • The follistatin and myostatin claims derive from cell-culture observations, not measured human outcomes.
  • Absence of data is not evidence of safety — nothing about tolerability in humans is established.

What the literature shows

In-vitro studies reported that YK-11 induced follistatin expression in myoblast cultures, which is the origin of the myostatin-inhibitor marketing claim.

Further cell work described partial androgen receptor agonism with a steroidal backbone, distinguishing it from compounds such as ostarine.

No published pharmacokinetic data exist in any species, so dose translation from cell culture concentrations is not possible.

SARM adverse-event and analytical literature includes YK-11 among compounds detected in unregulated products.

What remains unknown

  • Bioavailability, half-life and metabolism in humans are all unknown.
  • No safe or studied dose range exists to reference.
  • Hepatic, cardiovascular and endocrine effects are entirely uncharacterised.

Safety and monitoring implications

  • There is no human evidence base from which to derive monitoring, dosing or risk expectations.
  • Its steroidal structure means hepatic and lipid effects associated with oral steroids are plausible but unmeasured.
  • Community protocols for this compound are constructed from other compounds' data, not its own.

Cited literature

  1. 1.Kanno Y, Ota R, Someya K, et al. (2013). Selective androgen receptor modulator, YK11, regulates myogenic differentiation of C2C12 myoblasts by follistatin expression. Biological & Pharmaceutical Bulletin. Find on PubMed
  2. 2.Kanno Y, Hikosaka R, Zhang SY, et al. (2011). (17α,20E)-17,20-[(1-methoxyethylidene)bis(oxy)]-3-oxo-19-norpregna-4,20-diene-21-carboxylic acid methyl ester (YK11) is a partial agonist of the androgen receptor. Biological & Pharmaceutical Bulletin. Find on PubMed
  3. 3.Hilkens L, Cruyff M, Woertman L, et al. (2021). Use of and attitudes towards SARMs and other performance-enhancing substances. Frontiers in Psychiatry. Find on PubMed

Community reports

Anecdotal — not scientific evidence

Lived experience is valuable context and often surfaces problems before the literature does. It is also uncontrolled, unverified and subject to bias, so it never overrides published findings here.

Aggregated community threads

Mixed

Reports are polarised: some describe pronounced strength changes, others describe nothing beyond joint discomfort and fatigue.

Harm-reduction discussion groups

Negative

Commonly discouraged even within pro-use communities on the grounds that nothing is known about it in humans.

Buying YK-11 in Australia: what to check first

APEDRA does not sell YK-11 or any other product, and takes no commission from suppliers. If you are researching where to buy it, the biggest practical risk is not the compound itself but what is actually in the bottle: under-dosing, substitution with a different compound, and contamination are all documented in independent testing of online research chemicals.

  • Ask for a batch-specific third-party lab report (HPLC/mass spectrometry), not a generic certificate.
  • Check independent review platforms, not only reviews hosted on the seller's own site.
  • Read the shipping, returns and refund policies before ordering.
  • Be wary of prices far below the market or exaggerated results claims.

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Terms used here are defined in our glossary, and the evidence-grading scale explains what this analysis's grade means. If you believe something here is wrong, tell us.

This analysis is educational. It is not medical advice, a dosing recommendation, or an endorsement of use. Speak with a qualified medical practitioner about your circumstances.