text: EPA and DHA are available as dietary supplements most commonly as fish oil capsules, softgels, and gummies,1 krill oil, and less commonly as algae oil.2 Generally, salmon oil has more DHA than EPA while other fish oils such as herring, mackerel, anchovies, sardines, and pollock have more EPA than DHA. (See Supplements section below.)
  For comparison, note the omega-3 levels in some common non-fish foods:
  Health effects
  History
  Fish oil became one of the earliest dietary supplements, and by the end of the 19th century, was used as a treatment for many diseases, including such ailments as tuberculosis and hysteria. The possible effects of fish oil and omega-3 fatty acids have since been studied in clinical depression, anxiety, cancer, and macular degeneration, yet they have not been proven effective.
  Various recommendations
  In a 2009 letter on a pending revision to the Dietary Guidelines for Americans, the American Heart Association recommended 250–500 mg/day of EPA and DHA. The Guidelines were revised again for 2015–2020; included is a recommendation that adults consume at least eight ounces of a variety of types of fish per week, equating to at least 250 mg/day of EPA + DHA. The Food and Drug Administration recommends not exceeding 3 grams per day of EPA + DHA from all sources, with no more than 2 grams per day from dietary supplements.