MK-677 vs Tesamorelin
Well Studied vs FDA Approved
monitor Mechanism-based · 47% Both MK-677 and Tesamorelin affect insulin sensitivity or blood glucose. Monitor fasting glucose and HbA1c. Consider adding an insulin sensitizer (metformin/berberine).
Molecular Data
MK-677 Tesamorelin
Weight 624.77 Da 5,135.9 Da
Half-life ~24 hours 26-38 minutes
Chain — 44 amino acids
Type Non-peptide ghrelin receptor agonist GHRH analog
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)
Tesamorelin
01 FDA-approved formulation
02 Selective visceral fat targeting (15-20% reduction)
03 Proven clinical efficacy
04 Standardized dosing
05 37% liver fat reduction in NAFLD
06 Preserved subcutaneous fat
Dosing Protocols
MK-677
Start 12.5mg daily, increase to 25mg based on tolerance / Once daily, preferably at bedtime on empty stomach
Tesamorelin
1.4-2mg daily (FDA-approved: 2mg for HIV lipodystrophy) / Once daily (evening preferred for GH rhythm)
HIV Lipodystrophy (FDA-approved) 1.4mg Once daily
Visceral Fat Reduction 2mg Once daily
Anti-aging/Body Composition 1-2mg 5-7x weekly
NAFLD Treatment 2mg Once daily (12 months)
Cognitive Enhancement 1mg Once daily (20 weeks)
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.
Tesamorelin
Injection site reactions (17%)
Joint pain (13%)
Water retention
Contraindications
Heart disease or congestive heart failure
Diabetes or pre-diabetes
Active cancer
Severe cardiovascular disease
Pregnancy or breastfeeding
Active malignancy
Pituitary disorders
Pregnancy
Research Evidence
MK-677 Tesamorelin
Status Well Studied FDA Approved
References 7 studies 5 studies
Latest July 2024 June 2025
FDA Approved No Yes
This comparison is for educational and research purposes only. Consult a healthcare professional before use.