When reading labels and comparing the best omega-3 supplements, you may notice there are several types of omega-3s out there. That can make things seem a little confusing, but it's actually as simple as where the omega-3s are sourced from.  There are three types of omega-3s that you'll find on a supplement label: Docosahexaenoic acid, or DHA -- mostly found in cold-water fish like salmon and tuna Eicosapentaenoic acid, or EPA -- also found in cold-water fish Alpha-linolenic acid, or ALA) -- can be found in seeds, oils and nuts like walnuts, hemp seeds and vegetable oil