MK-677 vs Rapamycin
Well Studied vs FDA Approved
monitor Mechanism-based · 47% Both MK-677 and Rapamycin affect insulin sensitivity or blood glucose. Monitor fasting glucose and HbA1c. Consider adding an insulin sensitizer (metformin/berberine).
Molecular Data
MK-677 Rapamycin
Weight 624.77 Da 914.17 Da
Half-life ~24 hours ~62 hours
Type Non-peptide ghrelin receptor agonist Macrolide lactone (C51H79NO13)
Key Benefits
MK-677
01 97% increase in 24-hour growth hormone secretion
02 40-72% elevation in IGF-1 levels
03 Enhanced sleep quality with improved REM patterns
04 Preferential lean tissue gains of 1.1-2.7kg over 8-12 months
05 15% basal metabolic rate increase within 2 weeks
06 Oral administration (no injections required)
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-677
Appetite stimulation (>50% of users)
Water retention (30-40%)
Lethargy (20-30%)
Fasting glucose elevation (5-15mg/dL)
Note on testosterone suppression: at doses up to 20 mg daily, MK-677 is unlikely to cause significant testosterone suppression on its own. Above 20 mg daily, the likelihood of suppression and other side effects (insulin resistance, water retention, lethargy) increases. The case report documenting 85.7% testosterone suppression involved co-administration with LGD-4033, a SARM known to be profoundly suppressive, making the SARM the likely primary driver of that suppression.
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
Heart disease or congestive heart failure
Diabetes or pre-diabetes
Active cancer
Severe cardiovascular disease
Pregnancy or breastfeeding
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-677 Rapamycin
Status Well Studied FDA Approved
References 7 studies 5 studies
Latest July 2024 March 2023
FDA Approved No Yes
This comparison is for educational and research purposes only. Consult a healthcare professional before use.