DHA is an omega-3 fatty acid, chemically it is a carboxylic acid with a 22-carbon chain and six cis double bonds. Its chemical formula is C22H32O2 and Mol. Mass is 328.488 g/mol. Fish oils are the primary source of DHA. Research is being done on its application in treatment of Alzheimer's disease. It is also used as a supplement by pregnant women because studies indicate that low levels of erythrocyte DHA are associated with poor retinal development, low visual acuity, and poor cognitive development. DHA is becoming popular as a supplement for infants because it promotes healthy brain development and makes infants gain weight faster.

EPA (Eicosapentaenoic Acid), also known as icosapentaenoic acid and EPA, is a omega 3 fatty acid, a carboxylic acid which acts as a precursor for prostaglandin 3, thromboxane 3 and leukotriene 5 groups of eicosanoids. It is mostly found in fish oil, but can also be contained in human breast milk. In recent times, sources from microalgae have been preferred, due to the large quantities of toxins contained in fish swimming in polluted waters. Human body can produce EPA out of alpha linoleic acid, but since that ALA is an essential fatty acid, only excess amounts would be converted. EPA has been subject to studies pertaining to the use in treatment of schizophrenia, but it may also lower suicidal tendencies. Further use as breast cancer progression inhibitor is under investigation.

Omega-3 fatty acids are polyunsaturated fatty acids (PUFAs) that are considered to be an essential fatty acid. Omega 3 can be found in seafood and fishes such as tuna, and salmon. It is commonly known as fatty acid that is good for the heart. It also helps reduce the risk of cardiovascular diseases by controlling the cholesterol level and blood pressure level. It plays an important role in the efficient function of the brain. It helps in improving the cognitive functions of the brain such as memory and performance; and also aids in the behavioural function of the brain. It also fights fatigue, prevents diabetes, improves dry skin and blood circulation. It also prevents osteoporosis.