GHRP-6 vs MK-677
Well Studied vs Well Studied
monitor Mechanism-based · 51% Both GHRP-6 and MK-677 stimulate the ghrelin receptor. Additive GH release may increase side effects (water retention, joint pain, blood glucose elevation). Consider using one at a time or reducing doses.
Molecular Data
GHRP-6 MK-677
Weight 873 Da 624.77 Da
Half-life 15-60 minutes ~24 hours
Chain 6 amino acids —
Type Synthetic hexapeptide Non-peptide ghrelin receptor agonist
Key Benefits
GHRP-6
01 Potent stimulation of natural growth hormone release
02 Significant increase in appetite (beneficial for bulking/weight gain)
03 Enhanced muscle growth through elevated GH and IGF-1
04 Improved fat metabolism and body composition
05 Cardioprotective effects observed in research
06 Enhanced recovery from exercise and injury
07 Cytoprotective and anti-inflammatory properties
08 Maintains natural GH pulsatile release
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)
Dosing Protocols
GHRP-6
100-300 mcg per injection / 2-3 times daily (morning, post-workout optional, before bed)
GH optimization 100 mcg 2-3x daily
Enhanced results 200-300 mcg 2-3x daily
With GHRH (synergy) 100 mcg each 2-3x daily
Appetite/bulking 100-200 mcg Before meals
MK-677
Start 12.5mg daily, increase to 25mg based on tolerance / Once daily, preferably at bedtime on empty stomach
Side Effects
GHRP-6
Intense hunger/increased appetite (most notable side effect)
Water retention
Tingling or numbness in extremities
Tiredness or lethargy after injection
Mild headache
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.
Contraindications
Active cancer or history of cancer
Pregnancy or breastfeeding
Pituitary disorders
Diabetes (use with caution)
WADA prohibited for competitive athletes
Heart disease or congestive heart failure
Diabetes or pre-diabetes
Active cancer
Severe cardiovascular disease
Pregnancy or breastfeeding
Research Evidence
GHRP-6 MK-677
Status Well Studied Well Studied
References 3 studies 7 studies
Latest — July 2024
FDA Approved No No
This comparison is for educational and research purposes only. Consult a healthcare professional before use.