Understand the source comparison
Melanotan I vs Melanotan II: Receptor Selectivity Comparison
MC1R Selectivity High (13x selective for MC1R) Low (non-selective across MC1R, MC3R, MC4R, MC5R) MT-I produces pigmentation with fewer systemic side effects but requires higher cumulative dose Pigmentation Speed Moderate (2–3 weeks to plateau) Rapid (7–10 days
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This page preserves a source comparison for education. It does not add a rating, recommendation or clinical judgment.
- MC1R Selectivity
- High (13x selective for MC1R)
- Low (non-selective across MC1R, MC3R, MC4R, MC5R)
- MT-I produces pigmentation with fewer systemic side effects but requires higher cumulative dose
- Pigmentation Speed
- Moderate (2–3 weeks to plateau)
- Rapid (7–10 days to plateau)
- MT-II's faster onset reflects higher receptor affinity and broader melanocortin activation
- Nausea Incidence
- 15–25% of users during loading
- 40–60% of users during loading
- MT-II's MC4R activity in the hypothalamus drives nausea. Dose-dependent and tolerance develops
- Sexual Side Effects
- Minimal to none
- Common (spontaneous erections, increased libido)
- MT-II's MC3R/MC4R activity affects sexual arousal pathways. Not present with MT-I
- FDA Approval Status
- Approved for erythropoietic protoporphyria (rare disease)
- Not FDA-approved for any indication
- MT-I (Scenesse) has regulatory approval; MT-II remains research-only with no clinical approval
- Typical Research Dose
- 0.5–1mg daily (loading), 16mg total cumulative
- 0.25–0.5mg daily (loading), 7–10mg total cumulative
- MT-I requires longer loading due to lower receptor potency; MT-II reaches saturation faster