Docosahexaenoic acid 22:6 (DHA) is the most abundant omega-3 fatty acid in the brain and retina. DHA comprises more than 90% of the omega-3 polyunsaturated fatty acids (PUFAs) in the brain and 60% of the PUFAs in the retina. Fifty percent of the weight of a neuron’s plasma membrane is composed of DHA.