← DatabaseMelanocortin Agonist
Melanotan I
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A synthetic analog of alpha-MSH that stimulates melanin production; its identical molecule, afamelanotide, is an approved drug in some regions for a rare photosensitivity disorder, while generic "Melanotan I" sold for tanning is unregulated.
How it works
Melanotan I is a synthetic peptide modeled on a natural hormone called alpha-melanocyte-stimulating hormone (alpha-MSH). Alpha-MSH tells pigment-producing skin cells (melanocytes) to make more melanin, the pigment that darkens skin and provides some protection against ultraviolet light. Melanotan I is a more stable, longer-acting version of this signal.
The same molecule, under the name afamelanotide, has been developed as an approved prescription drug in some jurisdictions for erythropoietic protoporphyria (EPP), a rare inherited condition in which sunlight causes severe pain; there it is given as a controlled-release implant to increase protective skin pigment. Separately, "Melanotan I" is sold informally and used by people seeking a tan with less sun exposure, which is an unapproved, off-label use.
The distinction is important: the regulated pharmaceutical (afamelanotide) has defined labeling and oversight, whereas Melanotan I obtained from research-chemical or gray-market sources is unregulated, of uncertain purity, and not quality-controlled. This entry describes mechanism only and does not endorse self-administration; established information refers to how the approved product is used in clinical settings.
Mechanism · Detailed Analysis
Molecular targetMelanotan I (afamelanotide) is a synthetic analog of alpha-MSH that acts as an agonist at melanocortin receptors, with principal pigmentary action through the melanocortin-1 receptor (MC1R) on melanocytes. It is a relatively broad melanocortin agonist rather than a strictly MC1R-selective ligand.
Signaling & downstream effectsMC1R activation is Gs-coupled, raising intracellular cAMP and stimulating the transcription factor MITF, which upregulates melanogenic enzymes such as tyrosinase. The result is increased production of eumelanin, leading to skin darkening and enhanced photoprotection. Melanocortin receptors elsewhere can also be engaged, which underlies some non-pigmentary effects.
PharmacokineticsAs the approved drug afamelanotide, it is formulated as a subcutaneous controlled-release implant designed to deliver the peptide over an extended period; amino-acid substitutions confer greater metabolic stability and potency than native alpha-MSH. Pharmacokinetics of unregulated injectable "Melanotan I" are not standardized.
CaveatsApproved use (afamelanotide) is limited to a specific indication under medical supervision; the generic tanning use of Melanotan I is unapproved and uses unregulated material. Increased and changing pigmentation warrants dermatologic monitoring of moles, and broad melanocortin activity can produce additional effects; gray-market product quality and sterility are not assured.
Published EvidenceLoading cited studies from PubMed…
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Educational aggregation of public literature. Not medical advice and not a recommendation to use any compound. Many compounds here are not approved for human use. Consult a licensed clinician.