Fish Oil Uses

What Is Fish Oil Used For?

Fish oil is primarily used as a source of the long-chain omega-3 fatty acids EPA and DHA. These fatty acids are found naturally in fatty fish and play structural and regulatory roles throughout the body.

Fish oil supplements are widely marketed for many purposes, but the strength of the scientific evidence varies considerably. Some uses are well established, while others remain subjects of ongoing research.

Triglyceride Reduction

The best-established medical use of high-dose omega-3 fatty acids is lowering elevated blood triglycerides. Prescription omega-3 products containing EPA, or combinations of EPA and DHA, can significantly reduce triglyceride levels.

These prescription products are standardized medications and should not be confused with ordinary fish oil capsules sold as dietary supplements. For more information, see Dosage of Fish Oil.

Fish Oil and Heart Health

Fish and seafood are part of heart-healthy dietary patterns. EPA and DHA may influence triglycerides, heart rhythm, blood vessels and inflammatory pathways, but taking a fish oil supplement is not equivalent to eating fish.

For most people without established cardiovascular disease or very high triglycerides, major health organizations emphasize eating fish regularly rather than routinely taking omega-3 supplements for prevention.

Inflammation and Joint Health

EPA and DHA participate in pathways involved in inflammation. Omega-3 supplements have therefore been studied in inflammatory disorders, particularly rheumatoid arthritis.

Some studies suggest that omega-3 supplementation may modestly improve certain symptoms or reduce the need for anti-inflammatory medication in people with rheumatoid arthritis. Fish oil is best considered a possible complementary nutritional approach rather than a treatment that replaces standard medical care.

Brain and Eye Function

DHA is an important structural component of the brain and retina. Adequate omega-3 intake is therefore relevant to normal neurological and visual development.

Omega-3 supplements have also been investigated for depression, cognitive decline and a variety of neurological conditions, but research results are mixed. Fish oil should not be presented as a proven treatment for depression, dementia, multiple sclerosis or other neurological diseases.

Pregnancy and Development

DHA plays an important role during fetal and infant development. Fish can provide DHA together with protein, iodine, selenium, vitamin D and other nutrients.

The FDA and EPA recommend that people who are pregnant or breastfeeding eat a variety of fish that are lower in mercury rather than avoiding fish altogether. Their current advice recommends 2 to 3 servings per week from the “Best Choices” category.

See the FDA advice about eating fish for current guidance about mercury and seafood choices.

Skin and Hair

Omega-3 fatty acids are components of cell membranes and contribute to normal nutrition, but claims that fish oil reliably treats acne, prevents hair loss or dramatically improves skin and hair have not been established to the same degree as its effect on triglycerides.

A balanced diet that supplies essential fatty acids, protein, vitamins and minerals remains more important for normal skin and hair than any single supplement.

Fish Oil Is Not a Universal Treatment

Fish oil has been studied in a remarkably wide range of conditions, which sometimes leads to the impression that it is a treatment for almost everything. A research association or a small preliminary study, however, is not the same thing as a demonstrated clinical benefit.

The most useful approach is to distinguish ordinary nutritional intake from high-dose therapeutic omega-3 use and to consider the actual amounts of EPA and DHA in a product rather than simply the number of milligrams of “fish oil” on the front of the bottle.

For an overview of the evidence, see the NIH omega-3 fatty acids fact sheet.