MK-2866 vs Rapamycin
Moderate Research vs FDA Approved
monitor Mechanism-based · 47% Both MK-2866 and Rapamycin negatively affect lipid profiles. Combined use may significantly worsen HDL/LDL ratios. Include lipid support and get bloodwork mid-cycle.
Molecular Data
MK-2866 Rapamycin
Weight 389.33 Da 914.17 Da
Half-life ~24 hours ~62 hours
Type Non-steroidal selective androgen receptor modulator (C19H14F3N3O3) Macrolide lactone (C51H79NO13)
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
Rapamycin
01 Lifespan extension demonstrated in every model organism tested (yeast, worms, flies, mice)
02 Upregulation of autophagy and cellular quality control mechanisms
03 Reduction of senescent cell burden and associated inflammatory secretome
04 Improved immune function at low pulsed doses (paradoxical immune enhancement)
05 Reduced age-related inflammation (inflammaging) via mTORC1 inhibition
06 Enhanced mitochondrial function and biogenesis
07 Potential reduction in age-related cancer risk through growth pathway suppression
08 Improved vaccine response in elderly populations at low intermittent doses
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
Rapamycin
Mouth sores / aphthous ulcers (most common, usually dose-dependent and self-limiting)
Mild lipid changes (elevated LDL cholesterol and triglycerides)
Temporary glucose elevation or mildly impaired fasting glucose
Mild gastrointestinal discomfort (nausea, loose stools)
Skin changes (mild acne, slower wound healing at injection/cut sites)
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
Active serious infection or immunocompromised state
Hypersensitivity to rapamycin/sirolimus or any macrolide compound
Severe hepatic impairment (rapamycin is extensively hepatically metabolized)
Planned major surgery within 2-4 weeks (impaired wound healing)
Pregnancy or breastfeeding
Concurrent use of strong CYP3A4 inhibitors without dose adjustment (ketoconazole, itraconazole, clarithromycin, grapefruit juice)
Research Evidence
MK-2866 Rapamycin
Status Moderate Research FDA Approved
References 5 studies 5 studies
Latest — March 2023
FDA Approved No Yes
This comparison is for educational and research purposes only. Consult a healthcare professional before use.