Melanotan I vs P21
A detailed comparison to help you understand the differences and choose the right peptide for your research goals.
Melanotan I
Melanotan I (afamelanotide) is a synthetic analog of alpha-melanocyte-stimulating hormone (α-MSH). It is FDA-approved as Scenesse for erythropoietic protoporphyria (EPP), a rare genetic disorder causing severe sun sensitivity.
Full details →P21
P21 is a synthetic peptide derived from Cerebrolysin, specifically designed to mimic the neurotrophic effects of the parent compound. It promotes neurogenesis and has shown cognitive-enhancing properties in research.
Full details →Side-by-Side Comparison
| Aspect | Melanotan I | P21 |
|---|---|---|
| Dose Range | 250 mcg–500 mcg | 1 mg–5 mg |
| Frequency | 1x daily | 1x daily |
| Cycle Length | 1–4 weeks | 2–4 weeks |
| Route | subcutaneous | subcutaneous |
| Mechanism | Binds to melanocortin 1 receptors (MC1R) on melanocytes, stimulating eumelanin production. This increases skin pigmentation and provides photoprotection without UV exposure. | Inhibits glycogen synthase kinase-3β (GSK-3β) and activates CREB signaling pathway. This promotes BDNF expression, neurogenesis in the hippocampus, and synaptic plasticity. |
| Typical Dosage | Clinical: 16mg implant every 2 months. Research protocols for tanning typically use 0.5-1mg daily for loading, then maintenance dosing. | Research protocols typically use 1-5mg administered intranasally or subcutaneously. Often used in cycles of 2-4 weeks. |
| Administration | FDA-approved form is a subcutaneous implant. Research use involves subcutaneous injection. Often combined with minimal UV exposure to enhance results. | Can be administered intranasally for direct CNS access or subcutaneously. Best used cyclically rather than continuously. |
| Side Effects | Nausea (especially initially), facial flushing, fatigue, headache, and darkening of existing moles or freckles. | Limited data. Reported effects include mild headache, temporary brain fog during initial use, and fatigue. |
| Best For |
Key Differences
Unique to Melanotan I:
Unique to P21:
Key Studies
Melanotan I
- Use of melanotan I and II in the general population.
BMJ (Clinical research ed.), 2009
- Pharmacologic response of a controlled-release PLGA formulation for the alpha-melanocyte stimulating hormone analog, Melanotan-I.
Pharmaceutical research, 2000
- Discovery and development of novel melanogenic drugs. Melanotan-I and -II.
Pharmaceutical biotechnology, 1998
Ready to Learn More?
Looking for trusted sources?