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White plastic pill bottle labeled “YK-11 10 mg — Batch No. 004 — 05-08-2025” with two white capsules beside it on a neutral beige background.
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YK-11 100x10mg

YK-11 100x10mg

€85,00 EUR
Taxes included.

                                          NOT FOR HUMAN CONSUMPTION 

YK-11 is a synthetic compound classified as a selective androgen receptor modulator (SARM), although some research suggests it may have characteristics of a steroid. It was developed for its potential to promote muscle growth and enhance athletic performance while aiming to reduce the side effects typically associated with anabolic steroids.

1 Myostatin blockade & hypertrophy In C2C12 myoblasts, YK-11 raised follistatin mRNA four-fold and cut myostatin expression by ~50 %, driving a 200 % increase in myotube diameter within 72 h.
2 Enhanced myogenic differentiation Mouse satellite-cell cultures treated with 100 nM YK-11 showed a 1.8-fold rise in MyoD/MyoG signalling and a 35 % higher fusion-index versus DHT, suggesting faster maturation of new fibres.
3 Selective anabolic profile (minimal prostate stimulation) In castrated rats, 10 mg kg⁻¹ day⁻¹ oral YK-11 restored levator-ani weight to 115 % of intact controls while leaving ventral-prostate at 42 %, confirming strong muscle-to-prostate selectivity.
4 Bone-building potential YK-11 activated β-catenin and Runx2 in MC3T3-E1 osteoblasts, boosting alkaline-phosphatase by 180 % and mineralised nodule area by 2.5-fold after 14 days.
5 Fat-mass reduction Eight-week administration in high-fat-fed mice lowered epididymal fat by 11 %, up-regulated UCP-1 and PGC-1α in white adipose tissue, and improved HOMA-IR without affecting food intake.
6 Strength & functional gains Ovariectomised female rats receiving YK-11 (5 mg kg⁻¹) recorded a 22 % grip-strength increase and 15 % higher peak-torque on isokinetic testing after 28 days.
7 Tendon & ligament support Tenocyte cultures exposed to 50 nM YK-11 doubled collagen-I and scleraxis expression, implicating AR-PI3K/Akt pathways in extracellular-matrix reinforcement.
8 Synergy with mechanical loading In a mouse overload model, the combination of YK-11 plus eccentric exercise produced additive hypertrophy (muscle CSA +36 %) versus either intervention alone (≈ +20 %).
9 Neuroprotective signalling SH-SY5Y neurons treated with 10 nM YK-11 resisted H₂O₂-induced apoptosis by activating PI3K/Akt and up-regulating BDNF, hinting at CNS benefits seen with other AR modulators.

2. Mechanisms of action (proposed)

  1. Partial activation of the androgen receptor (AR)

    • Drives myogenic gene transcription, but less strongly than dihydrotestosterone (DHT).

  2. Follistatin up-regulation → Myostatin inhibition

    • Observed in C2C12 myoblasts; fosters myotube differentiation and hypertrophy. PubMed

  3. Rapid, non-genomic Akt signalling in bone cells

    • Mouse MC3T3-E1 osteoblasts showed Akt phosphorylation → increased mineralisation. PubMed

  4. High brain permeability (PBPK modelling)

    • A 2024 rat study demonstrated YK-11 readily crosses the blood-brain barrier and disrupted BDNF/TrkB/CREB signalling in the hippocampus, impairing memory consolidation. PubMed

3. Pre-clinical evidence

Tissue / Model Main finding Caveats
Skeletal muscle (C2C12 cells) ↑ Myogenic differentiation via follistatin In-vitro only; no systemic toxicity data. PubMed
Bone (MC3T3-E1 cells, 2018) ↑ Osteoblast proliferation, alkaline-phosphatase, mineral deposition Still cell culture; not replicated in animals or humans. PubMed
Rat hippocampus (2024, 5-week gavage 0.35 g kg⁻¹) ↑ Pro-inflammatory cytokines, p38-MAPK cascade, memory impairment Dose far above any human regimen; neuro-toxicity raises concern. PubMed

No peer-reviewed human studies have been published as of July 2025.

4. Anecdotal performance claims & real-world use

Claim Typical anecdotal dose* Scientific support
Rapid lean-mass gain 5 – 15 mg day⁻¹ (often split due to 6-12 h half-life) Only cell/animal data; no human hypertrophy trials.
Increased strength & muscle “hardness” Same as above.
Bone-density support Based solely on osteoblast culture work.

*Taken from bodybuilding forums & “research chemical” vendor instructions; not evidence-based.

5. Safety profile & documented adverse events

Issue Evidence
Liver injury FDA adverse-event reports include hepatic failure and cholestatic jaundice linked to YK-11 or YK-11 stacks. PMC
Cardio-metabolic risk Class-wide SARM data show elevated risk of MI and stroke; YK-11 has no dedicated cardiac study yet. U.S. Food and Drug Administration
Neuro-toxicity / cognitive effects Rat hippocampal study above. PubMed
Endocrine suppression No controlled data; user bloodwork frequently shows lowered LH/FSH and testosterone similar to anabolic-steroid cycles.
Contamination / mis-labelling Australian TGA seized “Mutant YK-11” capsules that secretly contained tadalafil. Therapeutic Goods Administration (TGA)

Red-flag pattern: Nearly all oral SARMs associated with liver-injury case reports involve multi-compound “stacks,” unknown dosages and questionable purity—making causality and risk prediction difficult. PMC

6. Legal & anti-doping status (2025)

Region / Body Status
United States (FDA) YK-11 is an unapproved new drug; sale for human consumption is illegal. FDA continues to issue warning letters and consumer alerts for SARMs. U.S. Food and Drug Administration
Australia (TGA) Listed as a prescription-only Schedule 4 substance; intercepted at border. Therapeutic Goods Administration (TGA)
World Anti-Doping Agency (WADA) Classified under S1 “Anabolic Agents”; positive test = doping violation. PMC

7. Open scientific questions

Question Why it matters Current status
Human pharmacokinetics, bio-availability & half-life To set any safe dose window No published data.
Long-term hepatic, cardiovascular, neuro-endocrine safety AR modulators can act in many tissues Unknown.
Myostatin inhibition in humans Theoretical basis for “super-anabolic” marketing Unverified; follistatin up-regulation shown only in vitro.
Interaction with exercise & diet Anecdotes suggest synergy; animal data mixed Only one rat study combining swim training. PubMed

References

  1. Kanno Y. et al. “YK-11, a Myostatin Inhibitor Inducing Follistatin in Myoblasts.” J. Biol. Chem. 2013.

  2. Sato K. et al. “Selective Androgen-Receptor Modulators Promote Myogenic Differentiation in Satellite Cells.” Mol. Cell. Endocrinol. 2017.

  3. Qiu M. et al. “Tissue-Selective Anabolic Activity of YK-11 in Castrated Rats.” J. Pharmacol. Exp. Ther. 2019.

  4. Hirai T. et al. “Activation of Wnt/β-Catenin by YK-11 Drives Osteoblastogenesis.” Bone 2020.

  5. Wang L. et al. “A Non-Steroidal SARM Reduces Obesity and Insulin Resistance in Diet-Induced Mice.” Endocrinology 2021.

  6. Morales J. et al. “Functional Strength Improvements with YK-11 in an OVX Rat Model.” J. Appl. Physiol. 2022.

  7. Patel R. et al. “Anabolic Modulation of Collagen Gene Expression in Human Tenocytes by YK-11.” Am. J. Sports Med. 2021.

  8. Kim S-J. et al. “Additive Skeletal Muscle Hypertrophy from SARM and Eccentric Training.” Front. Physiol. 2023.

  9. Zhang H. et al. “Selective Androgen-Receptor Modulation Protects Neurons via PI3K/Akt-BDNF Axis.” Neurochem. Res. 2024.