A composition comprising (a) a sunless tanning agent and (b) an adjuvant for the sunless tanning agent, wherein the adjuvant comprises a pyrrole and/or indole derivative functionalized with a carbonyl group. Preferably, the pyrrole and/or indole derivative is of formula (I) or (II) wherein each R and R1 is independently hydrogen, C1-6alkyl, C1-3alkoxy, aryl, heteroaryl or C(=O)R*, where R* is H, C1-3alkyl, N(R**)2 or OR** and further where each R** is independently H or C1-4alkyl each R2 is independently H or C1-4alkyl X and Y are each O, S, NR3 or C(R3)2 and each R3 is independently H, C1-3alkyl, aryl or heteroaryl, with the proviso that at least one R and one R1 are a substitutent comprising a carbonyl group. In particular, the adjuvant is selected from 1-methyl-2-pyrrole-carboxylic acid, 1H-indole-2-carboxylic acid and pyrrole-2-carboxylic acid. Preferably, the sunless tanning agent is selected from the group including dihydroxyacetone, melanin, mahakanni, methyl glyoxal, erythrulose, alloxan, 2,3-dihydroxy succindialdehyde and mixtures thereof. A method of imparting a sunless tan to skin comprising the steps of applying the formulation to the skin is also outlined.
