Abstract: Quaternary ammonium salts of malic acid having the formula: ##EQU1## where: R is a monovalent aliphatic hydrocarbon radical, saturated or unsaturated, of from 8 to 20 carbon atoms but preferably of 12 to 18 carbon atoms; R.sub.1, R.sub.2, R.sub.3 may be identical or different and each represents a lower alkyl radical or an aryl radical. The salts find use in cosmetics as a source of the malic ions necessary to the energy process in cellular metabolism. These salts insure a better intracellular penetration of malic ion and improve the stability of creams and other cosmetic emulsions.