YK-11

YK-11 is a compound often classified as a Selective Androgen Receptor Modulator (SARM), though its structure is steroidal, setting it apart from most other non-steroidal SARMs.

It is also sometimes referred to as a Myostatin Inhibitor due to its unique mechanism of action.

Detailed Explanation (Different Name)

• Chemical Name: YK-11 is chemically a steroid derivative, closely related to Dihydrotestosterone (DHT).

• Common Name/Synonym: YK 11, YK-11, Myostine (referencing its myostatin-inhibiting effect).

• Classification: It is generally marketed as a SARM, but its steroidal backbone and mechanism that strongly involves inhibiting myostatin make it distinct. It functions as a partial agonist of the Androgen Receptor (AR).

Benefits (Purported)

• Enhanced Muscle Growth: YK-11 is reported to be highly anabolic. Unlike traditional SARMs, it has a dual mechanism:

  1. Partial Androgen Receptor Agonism: It binds to the AR, promoting anabolic signaling.

  2. Myostatin Inhibition: It significantly increases the expression of Follistatin, a natural antagonist of Myostatin. Myostatin is a protein that limits muscle growth; by inhibiting it, YK-11 allows for potentially greater muscle cell differentiation and hypertrophy (growth).

• Bone Health: Preclinical studies suggest it may have osteogenic activity, promoting bone cell proliferation and differentiation, which could be beneficial for conditions like osteoporosis.

• Minimal Androgenic Effects (claimed): As a SARM, it's theorized to preferentially target muscle and bone tissue, aiming to minimize the androgenic side effects typically associated with anabolic steroids (like prostate enlargement or hair loss).

Side Effects (Reported/Theorized)

Since YK-11 is an experimental compound and has not been approved for human medical use, its safety profile and long-term side effects are poorly understood and not clinically validated. Information is largely based on anecdotal user reports or extrapolated from its steroidal nature.

• Androgen Suppression: Being a partial AR agonist, it is likely to suppress natural testosterone production, requiring Post-Cycle Therapy (PCT) to restore hormonal balance.

• Hepatotoxicity (Liver Strain): Due to its steroidal structure, there is a potential risk of liver toxicity, which is a concern often associated with orally active anabolic steroids.

• Androgenic Side Effects: While marketed as selective, its steroidal structure suggests it may still pose a higher risk of typical androgenic side effects than non-steroidal SARMs, such as acne, increased aggression, and potential hair loss in genetically predisposed individuals.

• Cardiovascular Strain: Like many performance-enhancing drugs, there is a risk of negatively impacting cholesterol levels (lowering HDL "good" cholesterol and increasing LDL "bad" cholesterol).

Pros and Cons (Based on claims/preclinical data)

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Dosage and Frequency

Note: There are no standardized medical dosages for YK-11 as it is not an approved drug. User reports and suggested dosages vary widely, but common anecdotal ranges are:

• Dosage: 5 mg to 15 mg per day (some advanced users report up to 20 mg/day).

• Frequency: Typically taken once per day (ED) or divided into twice per day (BID) due to its short half-life.

Half-Life and Detection Time

• Half-Life: The exact, verified half-life in humans is not definitively established in clinical literature. Based on anecdotal reports and how users dose the compound, its half-life is estimated to be relatively short, often cited in the range of 5 to 10 hours. This is why users often divide the dose.

• Detection Time: YK-11 is banned by the World Anti-Doping Agency (WADA). Detection times can vary greatly based on the test type, sensitivity, metabolism, dosage, and duration of use.

  • One study investigating the metabolism of YK-11 for doping control found that some metabolites were traceable for more than 48 hours (2 days) in urine.

  • However, SARMs, in general, are often detectable for weeks or potentially over a month after cessation, particularly using modern, highly sensitive drug testing methods (LC-MS/MS).

Sterogenic, Progestronic, and Prolactin Effects

• Sterogenic: Yes. YK-11 has a steroidal backbone, chemically deriving from Dihydrotestosterone (DHT). This classifies it structurally as a steroidal SARM.

• Progestronic: Generally considered minimal/none. It is not typically reported to bind significantly to the Progesterone Receptor (PR), unlike some traditional anabolic steroids (like Nandrolone or Trenbolone) that can exhibit progestogenic activity.

• Prolactin: Generally considered minimal/none. Direct prolactin elevation is not a commonly reported or expected side effect, unlike compounds with progestogenic activity.

Anabolic Androgenic Ratio

The Anabolic Androgenic Ratio is a relative measure of a compound's muscle-building properties (Anabolic) versus its masculinizing properties (Androgenic), compared to Testosterone (which is 100:100 or 1:1).

• Numerical Ratio: A precise, clinically validated Anabolic:Androgenic Ratio for YK-11, determined through standardized in vivo (in a living organism) assays, is not available in the public scientific literature.

• Conceptually: YK-11 is designed to be a selective modulator, meaning its intended ratio would be highly favorable towards anabolism (e.g., 300:25 or similar), implying much stronger muscle-building effects than masculinizing effects. However, due to its steroidal structure, its actual androgenic score in non-muscle tissues may be higher than many non-steroidal SARMs.