YK-11: Research Compound Overview

Looking for YK 11 for your research? We recommend readers do their own research and use YK-11 for research purposes only.

What is YK-11?

Although it has steroid-like properties, YK-11 is not a steroid. YK-11 is used strictly for research purposes and is not approved for human consumption.

How Does YK-11 Work?

Stacking and Combination

Follistatin & Myostatin Inhibition: The Research Mechanism

YK11’s most distinctive feature in preclinical research is its dual mechanism: partial agonism of the androgen receptor (AR) combined with upregulation of follistatin, a natural inhibitor of myostatin (GDF-8).

How the Follistatin Pathway Works

In the Kanno et al. (2011, 2013) studies using C2C12 myoblast cell lines, YK11 was observed to:

• Upregulate follistatin expression via activation of the androgen receptor pathway
• Inhibit myostatin (GDF-8) signaling, removing a key constraint on myogenic differentiation
• Stimulate Follistatin-Like 3 (FSTL3), a secondary myostatin antagonist extending the inhibitory effect
• Activate Akt/PKB phosphorylation, a downstream pathway linked to protein synthesis

This mechanism differentiates YK11 from traditional SARMs, which act primarily through direct AR binding. The follistatin/myostatin axis may explain why researchers classify YK11 as a potential “myostatin inhibitor” — though this classification remains under scientific debate.

All mechanistic data cited here derives from in vitro (cell culture) studies. No human trials have investigated these pathways in vivo as of 2026.

Pharmacokinetic Profile: Steroidal Structure & Half-Life

Unlike most SARMs (LGD-4033, RAD-140, Ostarine) which use non-steroidal scaffolds, YK11 is structurally derived from 5α-dihydrotestosterone (DHT). This distinction has significant pharmacokinetic implications that current research literature does not fully address — representing one of the most significant data gaps in YK11 research.

Structural Properties

• C17-alpha methyl ester modification: The ester group at C17 may affect hepatic first-pass metabolism differently than C17-alpha alkylated steroids
• Molecular weight: 430.54 g/mol (CAS: 1370003-76-1); Molecular formula: C₂₅H₃₄O₆
• Steroidal backbone: More structurally similar to anabolic steroids than non-steroidal SARMs — potentially influencing SHBG binding and metabolic clearance
• No published human pharmacokinetic data: Half-life estimates (commonly cited as ~6–12 hours) are extrapolated from structural analogy with DHT metabolites, not measured human data

The gap between YK11’s steroidal architecture and the complete absence of human pharmacokinetic studies is an unresolved limitation that distinguishes it from more extensively studied compounds in the SARM class.

Hippocampal Neurochemistry: Emerging 2024–2025 Research

Research from 2024–2025 studying AR-active DHT-derived compounds suggests potential modulation of:

Critically, YK11’s partial agonism profile means CNS effects are not predictable from full-agonist testosterone data.

WADA 2026 Regulatory Classification

YK11 is classified under the World Anti-Doping Agency (WADA) 2026 Prohibited List as a non-approved anabolic agent (Section S1.2 — Other Anabolic Agents). This classification has been in effect since the early 2020s.

Jurisdiction	Classification	Current Status
WADA (International)	Prohibited — S1.2 Other Anabolic Agents	Banned in competitive sport (2026)
United States (FDA)	Not approved for human use; not a federally scheduled substance	Research use only
Canada (Health Canada)	Not an approved drug; enforcement warnings issued 2022–2024	Unapproved therapeutic
Australia (TGA)	Schedule 4 when compounded for prescription use	Regulated
United Kingdom	Not controlled under the Misuse of Drugs Act 1971	Research chemical

As of 2026, there are no registered clinical trials for YK11 in humans on ClinicalTrials.gov. The compound remains exclusively in the preclinical research phase, with all published mechanistic data from in vitro and rodent model studies.

YK11 vs RAD-140: Research Profile Comparison

A frequent research question is how YK11 compares mechanistically to RAD-140 (Testolone). The two compounds differ significantly in chemical origin, mechanism, and evidence base.

Parameter	YK11	RAD-140 (Testolone)
Chemical class	Steroidal (DHT derivative)	Non-steroidal (SARM)
Primary mechanism	Partial AR agonist + Follistatin upregulation	Full selective AR partial agonist
Myostatin inhibition	Yes — via follistatin/FSTL3 pathway	No direct myostatin pathway
Osteogenic activity	Yes — osteoblast stimulation observed in vitro	Minimal bone-specific data
Limited; hippocampal interactions emerging (2024–2025)
Human clinical trials	None (0 registered ClinicalTrials.gov entries)	Phase I completed; Phase II ongoing (breast cancer, 2025–2026)
WADA status (2026)	Prohibited — S1.2	Prohibited — S1.2
HPG axis suppression	Likely — AR agonism + steroidal structure both contribute	Documented in Phase I human trial data
Liver safety data	No human data; steroidal C17 modification raises monitoring consideration	No major hepatotoxicity signal in Phase I

The critical asymmetry: RAD-140 has progressed to human clinical trials, providing actual safety and pharmacokinetic data. YK11 has no equivalent human data — a fundamental evidence gap that should be considered when evaluating these compounds for research purposes.

Why Choose Loti Labs for YK-11?

Loti Labs is a trusted provider of high-quality research compounds at competitive prices. Many customers have given positive feedback and trust Loti Labs as a reliable supplier.

They offer third-party testing, Certificates of Analysis, fast shipping, and excellent customer service, making them a preferred choice for researchers. Loti Labs has a good reputation in the research compound market for quality and reliability.

YK-11 is in stock to fulfill all customer orders.

Quality Control

Each batch of YK-11 from Loti Labs is tested in an independent laboratory to verify purity and potency for research use.

Customer Service

Loti Labs provides good customer support to help researchers with questions and make the purchasing process smooth.

Pricing

Loti Labs offers competitive pricing with bulk discounts; YK-11 is affordable for research budgets.

Product Information

• Form: Viscous, cloudy liquid
• Concentration: 10 mg/ml
• Molecular Formula: C25H34O6
• CAS Number: 1370003-76-1
• Packaging: Available in 30 ml bottles of liquid or bottles with capsules
• Availability: Liquid and capsule forms available

YK-11 can be purchased for research purposes in many countries but is not for human consumption.

Buy YK-11 Online

You can order YK-11 online at https://lotilabs.com. YK-11 is in stock for fast shipping. They offer quality products, good customer service, and competitive pricing for research.

FAQs

What is YK-11 and how is it classified?

YK-11 is a synthetic SARM and myostatin inhibitor used in research. It is not a steroid but shows some steroid-like properties in lab studies.

How does YK-11 work in research studies?

Why choose Loti Labs for YK-11?

Loti Labs provides high-quality research materials with third-party testing, competitive pricing, and good customer support for consistency and reliability in research.

What are the product specifications of YK-11 from Loti Labs?

YK-11 is supplied in 30 ml bottles with a concentration of 10 mg/ml, viscous and cloudy in appearance, molecular formula C25H34O6, and CAS Number 1370003-76-1.

References

1. Kahn, B. B., & Flier, J. S. (2000). J Clin Invest, 106, 473-481. doi:10.1172/JCI10842
2. Lee, S. J., & McPherron, A. C. (2001). Proc Natl Acad Sci U S A, 98, 9306-9311. doi:10.1073/pnas.151270098
3. Schuelke, M., et al. (2004). N Engl J Med, 350, 2682-2688. doi:10.1056/NEJMoa0409334
4. Zhao, B., Wall, R. J., & Yang, J. (2005). Biochem Biophys Res Commun, 337, 248-255. doi:10.1016/j.bbrc.2005.08.1867
5. McPherron, A. C., Lawler, A. M., & Lee, S. J. (1997). Nature, 387, 83-90. doi:10.1038/387083a0
6. Grobet, L., et al. (1997). A myostatin mutation associated with double muscling in cattle. Nat Genet, 17, 71-74. doi:10.1038/ng0997-71