Effects of a potent synthetic melanotropin, Nle⁴-D-Phe⁷-α-MSH (Melanotan-I) on tanning: a dose-ranging study

Abstract

An open-label, dose-finding study of a superpotent melanotropic peptide [Nle⁴-D-Phe⁷]α-MSH_1-13, called Melanotan-I (MT-I), was performed in eight male volunteers with “tannable” skin types III-IV. This synthetic analog of α-melanocyte-stimulating hormone (α-MSH), was administered subcutaneously for 10 days at three dose levels of 0.16 mg/kg per dose, 0.26 mg/kg per dose and 0.4 mg/kg per dose. Skin pigmentation at eight anatomic sites was measured serially using light reflectance values quantitated as luminance (L-values) and blue-yellow hue (b-values). All subjects tanned during the course of the trial, but there was no evidence of improved tanning beyond that obtained at the 0.16 mg/kg dose (P = 0.04). The most responsive site of skin darkening was the forehead, followed by the cheek, chin, neck and forearm. The anterior leg and buttock did not darken. There were no toxicities of grade 2 or more by World Health Organization (WHO) criteria at the 0.16 mg/kg dose, whereas the two higher doses produced moderate gastrointestinal upset and some mild to moderate fatigue. The optimal dose for ten daily subcutaneous injections of this agent is 0.16 mg/kg per day.

Key Words:

• Synthetic melanotropin
• Tanning