Oleic acid is a fatty acid that occurs naturally in various animal and vegetable fats and oils. It is an odorless, colorless oil and is classified as a monounsaturated omega-9 fatty acid. It has the formula CH3(CH2)7CH=CH(CH2)7COOH. The name derives from the Latin word oleum, which means oil. It is the most common fatty acid in nature and is the most abundant fatty acid in human adipose tissue, and second in abundance in human tissues overall only to palmitic acid.
Fatty acids can be obtained by the saponification of triglycerides, which are the greasy materials in many natural oils. Triglycerides of oleic acid comprise the majority of olive oil. It also makes up 59-75% of pecan oil, 61% of canola oil, 36-67% of peanut oil, 60% of macadamia oil, 20-80% of sunflower oil, 15-20% of grape seed oil, sea buckthorn oil, and sesame oil, and 14% of poppy seed oil. High oleic variants of plant sources like sunflower (~80%) and canola oil (70%) has also been developed.
Popular oils used in the beauty and skin care world, which are rich in oleic acid include: shea butter, sesame oil, sunflower oil, coconut oil, macadamia nut oil and almond oil.