Afamelanotide (Melanotan I)

Afamelanotide is a synthetic, prolonged-action analog of alpha-melanocyte-stimulating hormone (α-MSH). Research names include Melanotan I and NDP-MSH. Clinuvel markets the medicine as Scenesse, a small bioresorbable implant inserted beneath the skin by a clinician. It releases the peptide over several days rather than requiring a daily injection.

The chemical identity overlaps with products advertised online as “Melanotan I,” but that does not make unregulated self-injection equivalent to the manufactured implant. Product quality, delivery and indication remain separate questions.

At the University of Arizona in the 1980s, Mac Hadley and Victor Hruby investigated whether a stable α-MSH analog could produce pigmentation without sunlight. They hypothesized that pigmentation induced without sun exposure might reduce skin-cancer risk; this was the historical rationale for the work, rather than an established clinical benefit. Natural α-MSH was too short-lived for the intended purpose. Their linear Melanotan I program became afamelanotide; the separate cyclic Melanotan II program eventually contributed to a medicine for sexual dysfunction.

Development shifted toward protecting people with severe light sensitivity. European authorization followed in 2014 and US approval in 2019 for erythropoietic protoporphyria (EPP). The older cosmetic-tanning idea persists in online Melanotan I/II sales, but those unapproved injections lack the regulated implant’s manufacturing controls. Regulators have warned against them.

Afamelanotide stimulates melanocortin-1 receptors on melanocytes. These cells then produce more eumelanin, the dark pigment that absorbs and scatters light and helps neutralize light-generated reactive oxygen species. Receptor activation can increase pigmentation without the ultraviolet damage ordinarily associated with tanning.

EPP causes protoporphyrin IX accumulation. Visible light interacting with that molecule generates reactive oxygen species, tissue injury and intense burning pain. Additional eumelanin reduces the light reaching susceptible tissue and can extend pain-free exposure. The peptide’s stability supports slow release from an implant.

A placebo-controlled experiment in 65 fair-skinned volunteers also demonstrated a pigmentation effect: average epidermal melanin density increased 41% in low-MED, burn-prone skin and 12% in high-MED skin. That observation concerns the molecule’s pharmacology, not the purity, efficacy or safety of online tanning vials.

The two pivotal placebo-controlled EPP trials reported in 2015 included 168 adults. Their exposure measurements and populations should be kept distinct:

Quality of life improved in both pivotal trials. Headache, nausea, nasopharyngitis and back pain were the common trial adverse events; mild implant-site hyperpigmentation affected about one third of treated participants. These results support medical photoprotection with the implant. Controlled human trials have not established the benefit or safety of unregulated self-injected Melanotan I for cosmetic tanning.

The FDA approved Scenesse in October 2019 to increase pain-free light exposure in adults with a history of EPP-related phototoxic reactions. The clinical literature identifies it as the only FDA-approved drug using melanin stimulation for photoprotection. Its earlier EU authorization was in 2014.

EPP is an inherited disorder that can make brief light exposure severely painful and restrict daily activities. The 2023 consensus guidance recommends afamelanotide to prevent EPP phototoxic symptoms. The approved use does not include cosmetic tanning or other conditions, and the implant is placed by a healthcare professional. A gray-market Melanotan I vial is neither an approved tanning medicine nor Scenesse.

Prescribing information lists implant-site reactions, nausea, throat pain or cough, fatigue, hyperpigmentation or darkened existing moles, dizziness or drowsiness, respiratory infections and skin irritation among common adverse effects. Postmarketing reports include severe hypersensitivity, including anaphylaxis.

Because treatment changes pigmentation and can darken moles, the label calls for full-body skin examinations twice yearly. Monitoring is intended to follow existing moles and assess suspicious lesions over time.