🔬 YK‑11 – Research Use Only

🧪 Chemical Identity

• Name: YK‑11 (Methyl (2E)-…acetate)

• Synonyms: Myostine; 17α‑methyl‑δ²‑17β‑hydroxyestra‑4,9‑dien‑3‑one

• CAS No.: 1370003‑76‑1; Formula: C₂₅H₃₄O₆ reddit.com+15en.wikipedia.org+15reddit.com+15

⚙️ Mechanism of Action

• Steroidal SARM/analogue: Binds androgen receptors (AR) as a partial agonist—unlike full agonists, it does not support classic N/C terminal interactions pathofpeds.com+5en.wikipedia.org+5wikibolics.com+5.

• Myostatin inhibition: Upregulates follistatin, reducing myostatin activity and promoting muscle differentiation in vitro pubmed.ncbi.nlm.nih.gov+10en.wikipedia.org+10publichealthlaw.net+10.

🔬 Research Applications & Evidence

• Enhanced muscle development: Improved growth in C2C12 myoblasts; superior anabolic activity vs. DHT in lab settings reddit.com+15en.wikipedia.org+15publichealthlaw.net+15.

• Bone health potential: May support osteoblast proliferation/mineralization, signaling through Akt pathway publichealthlaw.net+1steroiduck.com+1.

• Neurochemical effects: Animal study (~350 mg/kg in rats for 5 weeks) found hippocampal inflammation, oxidative stress, and memory impairments reddit.com+7pubmed.ncbi.nlm.nih.gov+7chemicalbook.com+7.

⚠️ Safety & Side Effects

• No approved clinical data: No human or formal animal clinical trials exist steroiduck.com+6selfhacked.com+6musclemastery.net+6.

• Potential liver toxicity: Derived from steroid structure; hepatotoxicity is a concern reddit.com+8sarms.io+8musclemastery.net+8.

• Hormonal suppression: Likely stronger than non-steroidal SARMs—common testosterone suppression noted nanotechproject.org+5musclemastery.net+5sarms.io+5.

• Joint/tendon issues: Frequently reported by users steroiduck.com+15sarms.io+15anabolica.net+15.

• Neurological risk: Anxiety, aggression, and potential panic; inflammation and oxidative stress in neuronal tissue .

⚠️ Regulatory & Ethical Notice

• Research-only substance: Not approved by FDA for human or veterinary use. Must include “Not for human use” on all documentation.

• Banned in sports: Listed on WADA’s prohibited list sarms.io+2selfhacked.com+2musclemastery.net+2.

• Unregulated gray-market risks: Purity and accurate labeling are not guaranteed outside certified lab suppliers selfhacked.com+2musclemastery.net+2pathofpeds.com+2.

🛠️ Handling & Storage Guidelines

• Form: ≥98 % purity research-grade powder or oral/injectable solution.

• Dosage (anecdotal only): 5–15 mg/day orally, often split doses; injectable dosing unstudied and potential for injection-site risks reddit.com+15selfhacked.com+15wikibolics.com+15.