J. Cosmet. Sci., 65, 81–87 (March/April 2014) 81 Oxidative stability of cosmetic argan oil: a one-year study SAID GHARBY, HICHAM HARHAR, BADR KARTAH, DOMINIQUE GUILLAUME, IMANE CHAFCHAOUNI-MOUSSAOUI, ZAKIA BOUZOUBAA, and ZOUBIDA CHARROUF, University Mohammed V-Agdal, Rabat, Morocco (S.G., H.H., B.K., Z.C.), University of Reims Champagne Ardenne, Reims, France (D. G.), Universiapolis, Agadir, Morocco (I. C.-M.), and INRA-CRRA Agadir, Morocco (Z.B.). Accepted for publication February 23, 2014. Synopsis The objective of this work is to determine the chemical stability of cosmetic argan oil (INCI: Argania spinosa kernel oil). The methodology involves the repeated measurement over a 1-year period of the quality metrics used in the cosmetic industry: acid and peroxide value and specifi c absorbance. During this year, storage is performed at 40° or 25°C to assess the importance of temperature. In this latter case, oil samples have been either protected or exposed to sunlight. In addition, sterol and fatty acid composition is determined to attest argan oil chemical integrity over 1 year. Storage of argan oil at 40°C results in a rapid loss of quality. Stored at 25°C and protected from sunlight, argan oil quality is still satisfactory after 12 months according to the offi cial Moroccan norm, but storage should not be longer than 6 months to fulfi ll industrial standards. INTRODUCTION The recent worldwide success of edible argan oil is only challenged by the concomitant global success of cosmetic argan oil (INCI: Argania spinosa kernel oil, CAS: 223747-87-3) (1). Whereas edible argan oil, which constitutes the basic ingredient of the Amazigh diet (2), is mainly prized for its hypocholesterolemiant properties (3), so far, cosmetic argan oil is sought for its skin antiaging moisturizing and conditioning, and hair-protecting capac- ity, not to mention its nail strengthening or emollient properties (4). Consequently, cos- metic argan oil is included in various cosmetic formulations as shampoo, lotion, skin-care cream, ointment, and facial makeup. Because of its limited supply and unprecedented success, argan oil has become the most expensive oil in the world in 2011 (1). Edible and cosmetic argan oils are prepared by cold-pressing argan kernels (5). Pressing roasted ker- nels affords edible argan oil while unroasted kernels are used to prepare cosmetic argan oil that is very pale gold-colored and whose taste is slightly bitter. Edible argan oil is copper- colored and presents a hazelnut taste mostly resulting from the presence of volatile Address all correspondence to D. Guillaume at dominique.guillaume@univ-reims.fr and Z. Charrouf at zcharrouf@menara.ma.