YK-11

evidence score

sarm

Research Only

23 studies

YK11steroidal SARM

YK-11 is a synthetic steroidal compound that acts as both a partial androgen receptor agonist and a myostatin inhibitor — making it structurally unique among compounds marketed as SARMs (it is more accurately classified as a synthetic steroid with SARM-like properties). In vitro data shows suppression of myostatin (MSTN) via Follistatin upregulation, potentially removing the primary biological brake on muscle growth. Exclusively in vitro evidence; no animal pharmacokinetic or efficacy data. No human data. The most speculative compound in common use.

Evidence

Moderate evidence

Safety

Unknown safety profile

Clinical Status

Preclinical

Research Sync

Feb 19, 2026

Dosing

Typical

5 mg

2 mgRange10 mg

FrequencyOnce or twice daily oral

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Pharmacology

Half-lifeUnknown

OnsetUnknown; in vitro effects only

DurationUnknown

Routes

oral

Evidence Score

Level B — Moderate

23 studies indexed

Scoring Factors

Volume(40%)~28/100

Quality(30%)~40/100

Sample Size(10%)~100/100

Consistency(10%)~100/100

Replication(5%)~100/100

Recency(5%)~100/100

Scores estimated from study counts. Exact breakdown computed after research sync.

Evidence Levels

AScore ≥75 with at least 1 meta-analysis and 3+ RCTs

BScore ≥50 with at least 1 RCT or meta-analysis

CScore ≥25 — observational or animal evidence only

DScore <25 — very limited or preclinical data

Plain-English Snapshot

YK-11 is currently categorized as a sarm compound.

Evidence is moderate (57/100): promising signal from 23 indexed studies, but context and population still matter.

Safety scoring is incomplete. Start conservatively and monitor carefully.

Core mechanism

Partial AR agonist with structural similarity to DHT; upregulates Follistatin to inhibit myostatin, potentially removing the ceiling on muscle hypertrophy

Practical Context

Strongest current signals

Level D: Detection of nonsteroidal and steroidal selective androgen receptor modulators in equine hair after oral administrations.
Level D: Discovery and optimization of novel indolecarboxylic acid derivative as potent glucagon-like peptide‑1 receptor agonists.
Level D: These data show that ORX in mice with renal injury is associated with changes in muscle growth and differentiation factors, and are informative for attempts to develop treatments for sarcopenia in patients with kidney disease.

Elevated caution signals

2 severe/high side effect flags