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Research profile · Peptide analogue

Melanotan I

Also known as Afamelanotide, NDP-MSH, [Nle4, D-Phe7]-alpha-MSH

Clinical — evidence level 4 of 4: Established clinical evidencePrescription only — UK regulatory status: Prescription-only medicine (UK)

Overview

The same molecule as afamelanotide, the active substance of an authorised medicine.

Category
Peptide analogue
Highest evidence level identified
Established clinical evidence
Last scientifically reviewed
20 August 2026
Last regulatory review
20 August 2026

Mechanism under investigation

Melanotan I is a synthetic thirteen-residue analogue of alpha-melanocyte-stimulating hormone, made by replacing the methionine at position 4 with norleucine and switching the phenylalanine at position 7 to its mirror-image form. Those two changes make it far more resistant to breakdown than the natural hormone. It acts at melanocortin receptors, principally the type 1 receptor on pigment cells, where it drives synthesis of eumelanin. Eumelanin absorbs ultraviolet and visible light strongly and reduces oxidative stress, which is the basis of the authorised medicine’s photoprotective use.

Research areas

  • Melanocortin signalling
  • Photobiology

These are fields in which the compound has been investigated. Listing a field is not a statement that anything was demonstrated within it.

Current evidence

In-vitro evidence

Cells, tissues or biochemical systems outside a living organism.

Well characterised as a melanocortin receptor agonist, and widely used as a reference agonist in receptor pharmacology.

Animal evidence

Studies in living non-human animals.

Established. The analogue series was developed through animal work on pigmentation.

Human observational evidence

Studies observing people without assigning an intervention.

Present, including post-authorisation safety surveillance of the licensed implant.

Clinical-trial evidence

Studies assigning an intervention to human participants.

Established to the standard required for a marketing authorisation, in the rare disease erythropoietic protoporphyria. Authorisation was granted under exceptional circumstances — a route used when comprehensive data cannot be obtained because the condition is too rare — and the Scottish Medicines Consortium accepted it for use in NHS Scotland.

Study limitations

  • The clinical evidence supports one narrow indication in a rare inherited condition, in a controlled-release implant given by a specialist. It does not transfer to any other purpose, formulation or route.
  • Authorisation under exceptional circumstances means the evidence base was accepted as necessarily incomplete because the disease is too rare to study conventionally. It is not equivalent to a standard authorisation.
  • Material sold as melanotan I is not the authorised product. It is neither the same formulation nor made to the same standard, and no regulator has assessed it.
  • Melanotan I and melanotan II are different molecules with different receptor selectivity. Nothing here applies to melanotan II, and the two are frequently conflated.

UK regulatory context

Prescription-only medicine (UK)

A medicine that may lawfully be supplied in the UK only against a prescription from an appropriate practitioner.

Source: Afamelanotide 16mg implant (Scenesse) — SMC advice (opens scottishmedicines.org.uk in a new tab) (Scottish Medicines Consortium)

Regulatory classification is jurisdiction-specific. A compound authorised elsewhere is not thereby authorised in the UK, and a supplier’s description of a substance does not determine how it is classified in law. See safety and regulation for the framework and the authoritative sources.

Safety and interpretation

The authorised product is prescribed only by specialist doctors in recognised centres and administered by clinicians trained to do so — that restriction is itself a statement about how its risks are managed. Because melanotan I stimulates pigmentation broadly, changes to existing moles and pigmented lesions are a recognised consideration, and the authorised product is used alongside skin monitoring. None of that supervision accompanies material bought outside the licensed route, and no regulator has assessed the identity, purity or sterility of such material.

References