MK-2866 vs Oxandrolone
Moderate Research vs Well Studied
avoid Mechanism-based · 64% Both MK-2866 and Oxandrolone 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 Oxandrolone
Weight 389.33 Da 306.44 Da
Half-life ~24 hours ~9-10 hours
Type Non-steroidal selective androgen receptor modulator (C19H14F3N3O3) 17-alpha-alkylated anabolic-androgenic steroid (C19H30O3)
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
Oxandrolone
01 Promotes lean muscle mass gains with minimal water retention
02 Supports recovery of lost body weight following surgery, trauma, or chronic illness
03 Reduces bone pain associated with osteoporosis and improves bone mineral density
04 Does not aromatize to estrogen, avoiding estrogen-related side effects
05 Well-studied safety profile in women, children, and burn patients
06 Enhances nitrogen retention and protein synthesis during caloric deficit
07 Attenuates glucocorticoid-induced catabolism in post-surgical and burn patients
08 Lower androgenic potency compared to most oral anabolic steroids
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
Oxandrolone
HDL cholesterol suppression (dose-dependent, most significant lipid effect)
LDL cholesterol elevation
Mild hepatic stress (elevated liver enzymes ALT/AST)
Suppression of endogenous testosterone production
Mild headaches
Nausea or gastrointestinal discomfort
Changes in libido (increase or decrease depending on hormonal context)
Oily skin and mild acne
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)
Nephrosis or nephrotic phase of nephritis
Hypercalcemia
Severe hepatic dysfunction or active liver disease
Hypersensitivity to oxandrolone or any formulation component
Research Evidence
MK-2866 Oxandrolone
Status Moderate Research Well Studied
References 5 studies 5 studies
Latest — September 2023
FDA Approved No Yes
This comparison is for educational and research purposes only. Consult a healthcare professional before use.