Linoleic acid (LA) is a naturally occurring fatty acid found predominantly in beef and dairy products. LA is one of the two essential fatty acids (the other is linolenic acid). Linoleic acid is an omega-6 fatty acid, meaning that it is unsaturated, with a double bond occurring at the sixth carbon atom from the omega end of the molecule. Conjugated linoleic acid (CLA) is an isomer of LA - which refers to a slight rearrangement of the molecular structure (conjugation) - resulting in a fatty acid with altered chemical functions. The rearrangement in this case is a conjugated double bond occurring at carbons 10 and 12 or at carbons 9 and 11. Linoleic acid is found in the diet in vegetable oils, whereas the conjugated variety, CLA, is found primarily in meat and dairy products. The form of CLA found most commonly in dietary supplements is manufactured from vegetable oils such as sunflower oil or safflower oil. One of the leading brands of CLA (TonalinTM), and the one on which the majority of studies has been conducted, is derived from safflower oil.