Melanotan products are designed to act on the same system the body uses to tan. Understanding that system makes the risks easier to understand.
Pigment-producing cells called melanocytes make two forms of melanin: eumelanin, a brown-black pigment, and pheomelanin, a red-yellow pigment. According to MedlinePlus Genetics: MC1R gene, eumelanin helps protect skin from ultraviolet (UV) damage, and pheomelanin does not.
The melanocortin 1 receptor (MC1R) sits mainly on the surface of melanocytes. When it's activated, the cell makes eumelanin. When it isn't activated or is blocked, the cell makes pheomelanin instead. MedlinePlus notes that common MC1R variants are most common in people with red hair, fair skin, freckles and increased sensitivity to the sun, and that certain variants increase the risk of melanoma.
UV exposure damages DNA in skin cells. Part of the skin's response is more melanocortin signaling and more melanin. In other words, a tan is a sign that UV damage has already happened. It's a response to injury, not a sign of healthy skin.
Melanotan I (afamelanotide) and Melanotan II are synthetic analogs of alpha-melanocyte-stimulating hormone (α-MSH), the body's natural activator of MC1R. Afamelanotide is approved in a regulated implant form for a specific rare condition (see afamelanotide (Scenesse)). Melanotan II acts on several melanocortin receptors, not just MC1R. That's one reason it's linked to effects beyond pigment, such as nausea and flushing (see reported side effects). Products sold online are unregulated.
People with MC1R variants, who burn easily, are the group most at risk from UV, and they're often the ones most tempted by tanning shortcuts. Safer options are in sunless tanning alternatives and sunscreen basics.
Published October 25, 2026. Sources are linked in the text. See our Medical Disclaimer.