MK-2866 vs Winstrol
Moderate Research vs Well Studied
avoid Mechanism-based · 64% Both MK-2866 and Winstrol carry hepatotoxic risk. Combining hepatotoxic compounds significantly increases liver damage potential. If unavoidable, include liver support (TUDCA/NAC) and monitor ALT/AST frequently.
Molecular Data
MK-2866 Winstrol
Weight 389.33 Da 328.49 Da
Half-life ~24 hours ~9 hours (oral), ~24 hours (injectable)
Type Non-steroidal selective androgen receptor modulator (C19H14F3N3O3) 17-alpha-alkylated anabolic-androgenic steroid (C21H32N2O)
Key Benefits
MK-2866
01 Increases lean body mass in a dose-dependent manner with clinical trial support
02 Preserves muscle mass during caloric deficit or catabolic conditions
03 Selective tissue activity reduces androgenic side effects compared to anabolic steroids
04 Oral bioavailability eliminates the need for injections
05 Does not aromatize to estrogen, avoiding gynecomastia and water retention
06 Improves physical function and stair-climbing power in clinical populations
07 Long 24-hour half-life allows convenient once-daily dosing
08 Mild side effect profile at commonly studied doses
Winstrol
01 Produces a dry, hard, and vascular appearance without water retention
02 Significant strength increases without proportional weight gain, favored in weight-class sports
03 Does not aromatize to estrogen, eliminating gynecomastia and bloating concerns
04 Potent suppression of SHBG, increasing free testosterone and enhancing the effectiveness of stacked compounds
05 Available in both oral and injectable formulations
06 High anabolic-to-androgenic ratio (320:30) relative to methyltestosterone
07 FDA-approved for hereditary angioedema prophylaxis
08 Enhances vascularity and muscle definition during caloric deficit
Dosing Protocols
MK-2866
10-25 mg/day oral / Once daily
Winstrol
25-50 mg/day (oral), 50 mg EOD (injectable) / Daily (oral) or every other day (injectable)
Performance - Standard Injectable 50 mg every other day Every other day (EOD)
Side Effects
MK-2866
Mild testosterone suppression (dose-dependent, typically 10-30% reduction at 25 mg)
HDL cholesterol reduction (10-20% suppression observed in clinical trials)
Headaches, particularly during the first 1-2 weeks
Mild back pain or muscle cramps
Transient fatigue toward the end of longer cycles
Slight reduction in libido at higher doses or extended cycle lengths
Winstrol
Severe HDL cholesterol suppression (winstrol is among the worst oral steroids for lipid damage)
Significant LDL cholesterol elevation
Joint dryness and pain, particularly in knees, shoulders, and elbows (notorious side effect)
Hepatic stress with elevated liver enzymes (ALT/AST)
Suppression of endogenous testosterone production
Hair loss and accelerated male pattern baldness (DHT derivative, particularly harsh on hairline)
Acne and oily skin
Tendon and ligament stress due to rapid strength gains combined with reduced joint lubrication
Dry, painful shin splints during cardiovascular exercise
Contraindications
Active liver disease or significantly elevated liver enzymes
Hormone-sensitive cancers (breast, prostate) without oncologist clearance
Pregnancy or breastfeeding (potential endocrine disruption to fetus/infant)
Individuals under 21 years of age (risk of premature HPTA disruption during development)
Concurrent use of hepatotoxic medications without liver function monitoring
Known hypersensitivity to MK-2866 or any formulation excipients
Competitive athletes subject to WADA or USADA anti-doping testing
Known or suspected prostate cancer
Breast cancer in males
Breast cancer with hypercalcemia in females
Pregnancy (Category X - known to cause fetal harm)
Severe hepatic dysfunction or active liver disease
Nephrosis or nephrotic phase of nephritis
Pre-existing severe cardiovascular disease or dyslipidemia
Hypersensitivity to stanozolol or any formulation component
Research Evidence
MK-2866 Winstrol
Status Moderate Research Well Studied
References 5 studies 5 studies
Latest — June 2023
FDA Approved No Yes
This comparison is for educational and research purposes only. Consult a healthcare professional before use.