GHRP-6 vs Retatrutide
Well Studied vs Extensively Studied
monitor Mechanism-based · 47% Both GHRP-6 and Retatrutide affect insulin sensitivity or blood glucose. Monitor fasting glucose and HbA1c. Consider adding an insulin sensitizer (metformin/berberine).
Molecular Data
GHRP-6 Retatrutide
Weight 873 Da 4,731.33 Da
Half-life 15-60 minutes ~6 days
Chain 6 amino acids 39 amino acids
Type Synthetic hexapeptide Triple GLP-1/GIP/glucagon 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
Retatrutide
01 Superior weight loss (24.2% at 48 weeks)
02 Improved glycemic control (HbA1c reduction up to 2.16%)
03 Enhanced cardiovascular benefits
04 Hepatic fat reduction (up to 82%)
05 Triple mechanism addresses obesity through multiple pathways
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
Retatrutide
0.5mg starting, titrate up to 8-12mg weekly / Once weekly (same day each week)
Starting Dose (Week 1-4) 0.5mg Once weekly
Low Maintenance (Week 4-8) 1mg Once weekly
Escalation (Week 8-12) 2mg Once weekly
Moderate (Week 12-16) 4mg Once weekly
Advanced (Week 16-20) 8mg Once weekly
Maximum Efficacy (Week 20+) 12mg Once weekly
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
Retatrutide
Gastrointestinal effects (nausea, vomiting, diarrhea)—typically mild to moderate
Heart rate increases—common especially in first 24 weeks
Appetite suppression
Mild dehydration
Contraindications
Active cancer or history of cancer
Pregnancy or breastfeeding
Pituitary disorders
Diabetes (use with caution)
WADA prohibited for competitive athletes
Personal or family history of medullary thyroid carcinoma
MEN2 syndrome
Severe renal impairment
Research Evidence
GHRP-6 Retatrutide
Status Well Studied Extensively Studied
References 3 studies 6 studies
Latest — 2025-10
FDA Approved No No
This comparison is for educational and research purposes only. Consult a healthcare professional before use.