ConsumerLab.com focused on supplements claiming to contain alpha-linoleic acid (ALA) or gamma-linolenic acid (GLA). ALA is an essential omega 3 fatty acid that can be converted, to a limited extent, into DHA and EPA—the omega 3 fatty acids found in fish oil. Flaxseed oil is extremely rich in ALA and is the dominant source for supplements. GLA is an omega 6 fatty acid that may be useful in treating diseases that involve pain and inflammation, including rheumatoid arthritis and cyclic mastalgia—breast pain associated with the menstrual cycle. Evening primrose, borage, and black currant oils are popular sources of GLA. Many of the products contained additional fatty acids, particularly linoleic acid (LA), which is an essential fatty acid found in many vegetable oils and generally abundant in the diet.
The study included supplements for pets as well as for people. Pet owners use omega 3 and 6 fatty acids for skin and coat maintenance.
Among the two products that failed testing, one was a softgel that contained only 79.8% of its labeled amount of oleic acid—a monounsaturated omega 9 fatty acid. The other was a bottled oil that contained only 84.2% of its labeled amount of omega 9 fatty acids. Both products, however, contained the claimed amounts of omega 3 and/or omega 6 fatty acids.