The FDA-approved melanocortin agonist for photoprotection
Injection · Prescription
Educational content. This page describes Melanotan 1 (Afamelanotide) for informational purposes only and is not medical advice, diagnosis, or treatment. Consult a licensed provider before starting, stopping, or modifying any therapy.
Researched and maintained by the PepHookup team. Regulatory status last verified April 12, 2026.
In the pivotal US Phase III trial, adults with erythropoietic protoporphyria spent a median 64.1 hours in direct sunlight on pain-free days over 180 days, versus 40.5 hours with placebo. This result is the basis for FDA approval.[1]
Selectively activates MC1R to drive synthesis of photoprotective eumelanin independent of sun exposure. In fair-skinned volunteers, melanin density rose by about 41% in those with the lowest baseline pigmentation.[2]
Melanotan 1, known by its International Nonproprietary Name afamelanotide, is a synthetic 13-amino-acid linear analog of alpha-melanocyte-stimulating hormone (alpha-MSH). Its chemical designation is [Nle4, D-Phe7]-alpha-MSH, reflecting two substitutions from the native hormone: norleucine replaces methionine at position 4 to prevent oxidative degradation, and D-phenylalanine replaces L-phenylalanine at position 7 to resist enzymatic breakdown. These changes make it more potent than native alpha-MSH and give it a much longer duration of action.
Afamelanotide is the first and only melanocortin-1 receptor agonist approved for therapeutic use. The FDA approved it in October 2019 under the brand name Scenesse to increase pain-free light exposure in adults with a history of phototoxic reactions from erythropoietic protoporphyria (EPP), a rare inherited disorder in which protoporphyrin IX accumulates and causes severe burning pain on exposure to light. The European Medicines Agency had approved it earlier, in 2014. It is manufactured by Clinuvel Pharmaceuticals as a 16 mg biodegradable subcutaneous implant.
It is important to distinguish afamelanotide from the gray-market tanning peptide marketed as Melanotan 2. Afamelanotide is a regulated, prescription-only medicine delivered as a controlled-release implant under specialist supervision, not a self-injected cosmetic tanning product.
Afamelanotide binds selectively to MC1R on the surface of melanocytes. This activates the Gs protein and adenylyl cyclase, raising intracellular cAMP and activating protein kinase A (PKA). PKA phosphorylates CREB and upregulates MITF, the master transcription factor for the pigment pathway. MITF then drives expression of tyrosinase, TRP-1, and TRP-2, the enzymes that produce eumelanin. The resulting brown-black eumelanin is deposited in the epidermis, where it absorbs light and scavenges free radicals.
Beyond pigmentation, MC1R-cAMP signaling activates a DNA repair pathway that operates independently of melanin production. PKA phosphorylates ATR (ataxia telangiectasia and Rad3-related protein) at serine 435, and this modified form recruits XPA, a core nucleotide excision repair factor, to sites of UV photodamage. The result is faster removal of cyclobutane pyrimidine dimers and 6-4 photoproducts. This repair-enhancing effect has been demonstrated in cultured human melanocytes and does not depend on pigment synthesis.
In EPP specifically, the thicker eumelanin layer absorbs the visible-light wavelengths that would otherwise excite the protoporphyrin IX accumulated in the skin and dermal blood vessels. By limiting how much light reaches that protoporphyrin, afamelanotide reduces the phototoxic reactions that otherwise confine these patients indoors.
The FDA-approved melanocortin agonist for photoprotection
Afamelanotide selectively activates MC1R on melanocytes, driving eumelanin synthesis through the cAMP/PKA/CREB/MITF cascade while simultaneously enhancing nucleotide excision repair through PKA-mediated ATR phosphorylation and XPA recruitment. Because it is MC1R-selective and does not meaningfully reach the central nervous system, it lacks the sexual and appetite effects associated with the non-selective peptide Melanotan 2.
In the US study, the median total hours in direct sunlight on pain-free days over 180 days was 64.1 with afamelanotide versus 40.5 with placebo (p=0.04). In the EU study over 270 days, the median was 6.0 versus 0.75 hours (p=0.005). These results supported FDA approval.
Langendonk JG, Balwani M, Anderson KE, et al. · N Engl J Med, 373(1):48-59 (2015) · PubMed
Subcutaneous afamelanotide increased melanin density by up to about 41% in those with the lowest baseline pigment. Epidermal sunburn cells fell by more than 50% and thymine dimer formation in the basal layer was reduced by 59% (p=0.002), evidence of both pigmentary and DNA-repair photoprotection.
Barnetson RS, Ooi TK, Zhuang L, et al. · J Invest Dermatol, 126(8):1869-1878 (2006) · PubMed
Alpha-melanocortin signaling reduced UV-induced DNA damage and apoptosis through MC1R, and a follow-up study defined the pathway: PKA phosphorylates ATR at Ser435, which recruits XPA to accelerate nucleotide excision repair. These effects were blunted in MC1R-deficient cells.
Kadekaro AL, Kavanagh R, Kanto H, et al. · Cancer Res, 65(10):4292-4299 (2005) · PubMed
Afamelanotide implants added to narrowband UVB achieved 48.6% repigmentation versus 33.3% with phototherapy alone by day 168, with faster facial response (41 versus 61 days, p=0.001) and a greater benefit in darker skin types. Vitiligo is not an FDA-approved indication.
Lim HW, Grimes PE, Agbai O, et al. · JAMA Dermatol, 151(1):42-50 (2015) · PubMed
Treated patients spent about 6 additional hours per week outdoors and reported clinically meaningful, sustained improvements in quality of life versus pre-treatment baseline. Adherence was high and the safety profile was favorable over the study period.
Wensink D, Wagenmakers MAEM, Barman-Aksözen J, et al. · JAMA Dermatol, 156(5):570-575 (2020) · PubMed
Over multiple years of follow-up, treated patients maintained quality-of-life gains with few adverse events and no new safety signals, supporting the long-term tolerability of repeated implants.
Biolcati G, Marchesini E, Sorge F, et al. · Br J Dermatol, 172(6):1601-1612 (2015) · PubMed
start low, go slow
Subcutaneous Implant (FDA-Approved)
Subcutaneous Injection (Research Only)
Subcutaneous Implant (FDA-Approved): Inserted above the anterior supra-iliac crest by a trained healthcare professional. The implant is a small poly(DL-lactide-co-glycolide) rod that releases the peptide over several days and then dissolves on its own.
Subcutaneous Injection (Research Only): The injectable form was used in the Barnetson photoprotection study. It has been superseded by the controlled-release implant for clinical use and is not the approved formulation.
Dosing and treatment intervals are determined by a licensed provider. Scenesse is prescribed and implanted only by healthcare professionals trained through the manufacturer's program, and it is not a self-administered medication.
The implant delivers controlled release over several days; the free peptide is cleared quickly, so the duration of effect comes from the depot rather than a long circulating half-life.
Because treatment can darken existing moles and freckles and may be associated with new pigmented lesions, a full-body skin examination is recommended approximately twice yearly during therapy.
Afamelanotide has been studied in multiple randomized controlled trials and several multi-year observational cohorts, giving it a well-characterized safety profile. A long-term observational study of 115 EPP patients and subsequent real-world cohorts found no new safety signals and high treatment continuation.
The most clinically relevant consideration is melanocytic change. Because treatment darkens nevi and can be associated with new pigmented lesions, the label recommends twice-yearly full-body skin examinations. No causal link to melanoma has been established, but monitoring is standard.
Serious hypersensitivity reactions, including anaphylaxis, have been reported and are a labeled warning. Because afamelanotide is MC1R-selective and does not meaningfully cross the blood-brain barrier, it lacks the central effects such as sexual arousal, appetite suppression, and intense nausea associated with the non-selective peptide Melanotan 2.
| Peptide | Primary Use | Administration | Cycle Length | Key Differentiator |
|---|---|---|---|---|
| Melanotan 1 (Afamelanotide) | Photoprotection in EPP | Subcutaneous implant | Every 2 months (ongoing) | The only FDA-approved melanocortin agonist, pairing eumelanin induction with UV-independent DNA repair through a selective MC1R mechanism |
| Melanotan 2 | Pigmentation and sexual function (no approved use) | Subcutaneous injection | About 2 weeks in published trials | Non-selective melanocortin agonist that produces tanning, sexual arousal, and appetite suppression together, paired with safety concerns that kept it from approval and led regulators to flag it |
| AHK-Cu | Hair & Skin Regeneration | Topical | 8 to 12 weeks | A hair follicle-focused copper tripeptide with a single supporting laboratory study and a biphasic dose response that makes formulation precision matter |
This peptide is an FDA-approved drug available via standard prescription.
FDA-approved as Scenesse for erythropoietic protoporphyria (EPP). Subcutaneous implant every 2 months. Approved for the narrow indication of photoprotection in EPP patients.
FDA approved Scenesse (afamelanotide 16 mg implant) to increase pain-free light exposure in adults with EPP
Last verified April 12, 2026. PepHookup tracks public FDA actions. This is not legal or medical advice.
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