YK11
A myostatin inhibitor with SARM-like properties that promotes muscle growth by increasing follistatin levels. Uniquely acts as both a selective androgen receptor modulator and myostatin inhibitor.
Beginner Basics
Plain-English guide to YK11
What it does
YK11 works by blocking a natural protein that limits muscle growth, while also triggering your body to make more of a muscle-building protein called follistatin. Researchers study it because it appears to help muscles grow larger and stronger.
Typical dose
Researchers typically use 5-10 mg once per day, injected under the skin. Most research cycles it for 8-12 weeks, then takes a 4-week break before starting again.
When to inject
Morning injections with food is the typical timing in research protocols.
Storage
Keep the dry powder in a freezer at -20°C (about -4°F). Once you mix it with water, store it in a regular refrigerator between 2-8°C (35-46°F) and keep it away from direct light.
First-timer tip
Start at the lower end of the dose range (5 mg) for your first cycle so you can see how your body responds before increasing, and always plan your 4-week break after 8-12 weeks of use.
On This Page
Research Status
Early Research
For research purposes only. Not approved for human use. Not medical advice.
Research Areas
Side Effects
YK11 is metabolized hepatically. Limited human data, but oral SARMs have shown liver enzyme elevation in some users. Monitor liver function tests (AST, ALT, bilirubin) if using. Discontinue if jaundice or severe abdominal pain develops.
As an AR modulator, YK11 may suppress endogenous testosterone production through negative feedback. Post-cycle therapy (PCT) with SERMs may be considered after 8-12 week cycles, though evidence is limited.
May occur with oral administration, especially on an empty stomach. Take with food to minimize. Usually resolves within days of continued use.
Reported anecdotally in some users. Typically mild and self-resolving. Ensure adequate hydration.
Possible due to androgen receptor activation. Maintain good skin hygiene and consider dermatologist consultation if severe.
Possible in genetically predisposed individuals due to AR activation in hair follicles. Risk may be lower than traditional steroids but is not zero. Discontinue if significant hair loss occurs.
Anecdotal reports of mood alterations. Monitor mental health and discontinue if significant mood disturbance occurs.
YK11 has not been studied in humans. Long-term safety, efficacy, and potential organ toxicity are unknown. Use carries inherent research risk.
Dosing Reference
| Parameter | Value |
|---|---|
| Dose range | 5-10 mg |
Frequency, timing and route - members only | |
Research disclaimer
Figures drawn from published research literature and community logs. Not clinical recommendations. Consult a qualified professional. Research use only.
Reconstitution Guide
Do not use saline or bacteriostatic saline, use only bacteriostatic water for reconstitution
Do not shake the vial vigorously; gentle swirling prevents peptide degradation
Discard immediately if the solution appears cloudy, discolored, or contains visible particles
Use within 30 days of reconstitution when stored at 2-8°C
Do not freeze the reconstituted solution; freezing may denature the peptide
Use the PeptideVolt reconstitution calculator for your exact concentration
Molecular and Pharmacological Data
YK11 functions as a selective androgen receptor (AR) modulator with dual activity as a myostatin inhibitor. It promotes muscle growth by increasing follistatin expression, which suppresses myostatin — a negative regulator of muscle mass. Unlike traditional anabolic steroids, YK11 exhibits tissue-selective effects and may promote myogenic differentiation with reduced virilization potential, though human safety data remains limited.
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View all peptidesResearch Use Only. All content on this page is provided for informational and educational purposes related to scientific research. YK11 is not approved for human use by the FDA or any equivalent regulatory body. This is not medical advice. Do not use any substance discussed here for therapeutic, diagnostic, or preventative purposes. Consult a qualified healthcare professional before making any health-related decisions. The Peptide Volt does not endorse the use of any research chemicals. 18+ only.