Description
YK11 has the CAS number 1370003-76-1 . Its molecular formula is C25H34O6. The molecular weight is 430.53 g/mol . The compound is a steroidal SARM. It is distinct from nonsteroidal SARMs like Ostarine or RAD140.
Mechanism of Action
YK11 acts as a partial agonist of the androgen receptor . It accelerates AR nuclear translocation. However, it does not induce N/C interaction . This explains its partially agonistic nature. Consequently, it acts as a gene-selective agonist. Its effects vary depending on the gene context .
Myostatin Inhibition Pathway
A key feature sets YK11 apart from other SARMs. It inhibits myostatin, a negative regulator of muscle growth . YK11 achieves this by upregulating follistatin . Follistatin is a potent antagonist of myostatin. Treatment with YK11 leads to significant follistatin mRNA expression. This effect does not occur with DHT treatment .
Research Applications and Preclinical Findings
Myogenic Differentiation
Research demonstrates YK11’s potent myogenic effects. In C2C12 myoblast cells, it induces myogenic differentiation . It enhances key myogenic regulatory factors (MRFs). These include Myf5, MyoD, and myogenin . Importantly, YK11 shows greater MRF induction than DHT. This is due to its unique follistatin-induction mechanism .
Osteogenic Activity
YK11 also exhibits osteogenic properties. In MC3T3-E1 osteoblast cells, it accelerates proliferation . It also enhances mineralization. Furthermore, it upregulates osteoblast differentiation markers. These include osteoprotegerin (OPG) and osteocalcin (OC) . The EC50 for AR-mediated transcriptional activation is 7.85 nM . The compound also activates the Akt signaling pathway. This occurs through rapid non-genomic signaling .
Potential Therapeutic Applications
Researchers have explored YK11 for several conditions. These include muscle wasting and sarcopenia. It has also been studied for sepsis-related muscle atrophy . Animal studies show it may reduce mortality in sepsis models. This occurs through myostatin inhibition . However, the compound remains investigational. It is not approved for human use.
Safety and Side Effect Profile
Neurotoxicity Concerns
A 2024 study raised significant safety concerns. The research examined YK11’s impact on the rat hippocampus . Physiologically Based Pharmacokinetic (PBPK) modeling demonstrated remarkable brain permeability . YK11 also showed inhibitory effects on 5-alpha-reductase type II .
Inflammatory and Apoptotic Effects
The 5-week experiment revealed concerning findings. YK11 increased pro-inflammatory cytokines. These included IL-1β and IL-6. Conversely, it reduced anti-inflammatory IL-10 levels . It also heightened p38 MAPK activity. This initiated an apoptotic cascade. The cascade involved Bax/Bcl-2/cleaved caspase-3 .
Memory and Cognitive Impact
The study concluded that YK11 significantly alters hippocampal neurochemistry. It downregulates BDNF/TrkB/CREB signaling. This occurs irrespective of exercise combination . Consequently, it leads to impairments in aversive memory consolidation . These findings underscore concerns about misuse risks. They challenge common perceptions of minimal side effects .
Metabolism and Detection
Metabolic Profile
A 2018 study examined YK11 metabolism . Researchers conducted an elimination study with deuterated YK11. They identified fourteen deuterated urinary metabolites . These included unconjugated, glucuronidated, and sulfoconjugated metabolites. Importantly, no intact YK11 was observed in urine samples .
Detection Window
Unconjugated metabolites disappeared within 24 hours . However, glucuronidated and sulfated metabolites remained traceable for more than 48 hours . This has implications for sports drug testing. WADA likely prohibits YK11 due to its anabolic properties.
Legal Status and Regulatory Actions
World Anti-Doping Agency (WADA)
WADA likely places YK11 on its prohibited list. It belongs to class S1.2 “Other Anabolic Agents”. Athletes cannot use it during or outside competition.
Regulatory Status
YK11 remains an unapproved drug. It cannot be legally sold as a dietary supplement. This applies in most countries. It is classified as a research chemical. Consequently, it is strictly intended for laboratory use only. Its steroidal backbone makes it more similar to traditional AAS than other SARMs.
Internal and External Links
Internal Resources
Visit our Research Chemical Library for related SARMs. Explore our Guide to Androgen Receptor Modulators. Review our Safety Protocols and Regulatory Compliance FAQ.
External Resources
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[PubMed]: Access the 2024 neurotoxicity study at PubMed.
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[ACS Omega]: Read the computational study at ACS Publications.
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[J-Stage]: View the original 2011 paper at J-Stage.
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[Benchchem]: Find research data at Benchchem.
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[MedChemExpress]: View chemical data at MedChemExpress.
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[WADA]: Check the prohibited list at WADA.
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