New — Free Peptide Starter Guide (2026): 13 chapters, 34 cited studies

Get it free
ToolsCompareRetatrutide vs Melanotan II

Retatrutide vs Melanotan II

Side-by-side comparison of key properties, dosing, and research.

GLP-1 / Weight Loss Agonists
Retatrutide
Sexual Health & Libido
Melanotan II
Summary
Retatrutide is an investigational triple receptor agonist targeting GLP-1, GIP, and glucagon receptors simultaneously. Phase 2 trials showed an unprecedented average 24% body weight reduction at 48 weeks — exceeding any approved medication to date. It is in Phase 3 trials as of 2024.
Melanotan II is a synthetic analog of alpha-melanocyte-stimulating hormone (α-MSH) that stimulates melanin production (skin tanning), suppresses appetite, and enhances sexual function. It is not FDA-approved and has significant safety concerns including mole changes and cardiovascular effects.
Half-Life
~10–12 days
1–2 hours
Admin Route
SubQ
SubQ
Research
Typical Dose
0.5 mg → 1 mg → 2 mg → 4 mg → 8 mg → 12 mg
0.25–0.5 mg
Frequency
Once weekly
Once daily
Key Benefits
  • ~24% body weight reduction at 48 weeks in Phase 2 (highest dose)
  • Superior to both semaglutide and tirzepatide in early trial comparisons
  • Triple receptor mechanism addresses multiple obesity pathways
  • Significant reduction in liver fat (MASH/NAFLD indication being studied)
  • Improved cardiovascular and metabolic markers
  • Once-weekly dosing
  • Potential for greatest weight loss of any currently investigated compound
  • Promotes skin tanning and melanin production
  • Reduces UV exposure needed to tan
  • Enhances libido and sexual function
  • May suppress appetite
  • Faster, deeper tan development
  • Longer-lasting tan maintenance
  • Potential photoprotective effects
Side Effects
  • Nausea and vomiting (common during titration, similar to semaglutide/tirzepatide)
  • Diarrhea
  • Constipation
  • Heart rate increase (from glucagon receptor agonism)
  • +2 more
  • Nausea (very common, especially in first days)
  • Facial flushing
  • Spontaneous erections in men
  • Darkening or changes in existing moles (monitor closely)
  • +3 more
Stacks With