Melanocortin-1-receptor agonists

Use of compound of formula (I) or a cosmetically acceptable salt of a compound of formula (I)

• wherein
• R1 is a C1-C10 alkyl group, a C3-C6 cycloalkyl group, an aryl group or an aryl C1-C6 alkyl group;
• R2 is an amino acid side chain of a basic amino acid or a 2-amino C2-8 alkanoic acid;
• R3 or R3′ are selected from the group consisting of H, an arylC1-C6 alkyl group or a heteroarylC1-C6 alkyl group, wherein the aryl respectively the heteroaryl can optionally be substituted;
• and
• R4 and R5 are, independently of each other, H or a C1-C10 alkyl group;
• and
• with the proviso that only one of R3 or R3′ is H and the respective other one of R3 and R3′ is not H
• as self-tanning or artificial/sunless tanning agent.

Cosmetic use of compound of formula (I) or a cosmetically acceptable salt of a compound of formula (I)

• wherein
• R1 is a C1-C10 alkyl group, a C3-C6 cycloalkyl group, an aryl group or an aryl C1-C6 alkyl group;
• R2 is an amino acid side chain of a basic amino acid or a 2-amino C2-8 alkanoic acid;
• R3 or R3′ are selected from the group consisting of H, an arylC1-C6 alkyl group or a heteroarylC1-C6 alkyl group, wherein the aryl respectively the heteroaryl can optionally be substituted;
• and
• R4 and R5 are, independently of each other, H or a C1-C10 alkyl group;
• and
• with the proviso that only one of R3 or R3′ is H and the respective other one of R3 and R3′ is not H for artificial/sunless tanning and/or browning of human skin, for the enhancement of the natural glow of the skin, for the protection of skin against UV-radiation and/or for the prevention of photoage-induced skin structure defects.