Cosmetic treatment comprises applying at least one layer of a mixture comprising a first composition comprising at least one exothermic metal salt, in anhydrous medium； and a second composition B comprising at least one slimming agent, in an aqueous medium, on keratin materials, where the mixture is obtained either extemporaneously before the application on keratin materials, or simultaneously on keratin materials. Independent claims are included for: (1) a cosmetic product comprising at least one first and the second cosmetic composition, separately from each other； and (2) a packaging set and distribution of compositions forming the product, comprising at least two independent compartments containing the compositions, which are distributed in two separate compositions or in mixture.
