Melanotan II is a synthetic cyclic heptapeptide analog of α-melanocyte-stimulating hormone that binds to melanocortin receptors, particularly MC1R and MC4R[1]. Activation of MC1R on melanocytes stimulates melanin production and distribution, resulting in increased skin pigmentation even without UV exposure[2]. Early Phase I studies in humans identified 0.025 mg/kg per day (approximately 1.5–2 mg for an average adult) as an appropriate dose, with measurable tanning observed after just five low doses administered over two weeks[1]. The peptide’s subcutaneous administration allows for steady melanocortin receptor activation, with effects accumulating over the course of daily injections during the initial tanning phase[3].
