Source comparison
Melanotan-1 vs Melanotan-2: Receptor Selectivity and Side Effect Profiles
Receptor Selectivity Highly selective for MC1R (melanocortin-1 receptor). Minimal binding to MC3R, MC4R, MC5R Non-selective. Binds MC1R, MC3R, MC4R, MC5R with similar affinity Melanotan-1's selectivity limits systemic effects; melanotan-2's promiscuity causes
This comparison does not assign a generated winner or score.
- Receptor Selectivity
- Highly selective for MC1R (melanocortin-1 receptor). Minimal binding to MC3R, MC4R, MC5R
- Non-selective. Binds MC1R, MC3R, MC4R, MC5R with similar affinity
- Melanotan-1's selectivity limits systemic effects; melanotan-2's promiscuity causes appetite suppression, sexual side effects, and nausea
- Half-Life
- ~33 minutes in plasma; effects persist weeks due to stable melanin production
- ~1 hour in plasma; pigmentation effects similar duration post-cessation
- Both require repeated dosing; neither offers true 'long-lasting' systemic presence
- FDA Status
- FDA-approved (Scenesse) for erythropoietic protoporphyria (EPP) as a subcutaneous implant
- Not FDA-approved; available only through research suppliers or compounding sources
- Melanotan-1 has clinical validation; melanotan-2 lacks formal safety data
- Primary Side Effects
- Injection site reactions, nausea (mild, transient), darkening of existing moles
- Nausea, flushing, appetite suppression, spontaneous erections, darkening of moles
- Melanotan-2's MC4R activation causes CNS effects absent with melanotan-1
- Dosing Protocol (Research Context)
- 0.16–0.25 mg/kg subcutaneous every 2–3 days or via sustained-release implant
- 0.5–2 mg subcutaneous daily during loading phase, then maintenance dosing
- Melanotan-1 protocols derive from clinical trials; melanotan-2 dosing is anecdotal
- The receptor specificity difference is what separates the two peptides functionally. Melanotan-1 binds almost exclusively to MC1R, the receptor responsible for pigmentation. Melanotan-2 binds to MC1R with similar affinity but also activates MC3R (involved in energy homeostasis) and MC4R (involved in appetite regulation, sexual function, and cardiovascular tone). This explains why melanotan-2 causes appetite suppression, nausea, and spontaneous erections. Effects entirely absent with melanotan-1. If your goal is pigmentation alone, melanotan-1's selectivity is an advantage. If you're using peptides in a research context exploring metabolic or sexual dysfunction pathways, melanotan-2's broader activity may be relevant, but it comes with a significantly higher side effect burden.