Fish oil is a dietary supplement derived from the tissues of oily fish. It is rich in omega-3 fatty acids, specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). High EPA formulations of fish oil emphasize a greater proportion of EPA relative to DHA. Both EPA and DHA are polyunsaturated fatty acids (PUFAs) that are essential nutrients, meaning the body cannot produce them in sufficient quantities and they must be obtained through diet or supplementation.
The primary sources of these omega-3s are cold-water fatty fish such as salmon, mackerel, tuna, herring, and sardines. Algal oil is a vegetarian/vegan alternative that provides DHA and, in some cases, EPA. Fish oil supplements are available in various forms, including triglycerides, ethyl esters, and re-esterified triglycerides, which can influence their absorption and bioavailability. The 'high EPA' designation typically means the EPA content significantly outweighs that of DHA, often with ratios like 2:1 or even higher. This specific formulation is often explored for its distinct physiological effects compared to balanced EPA/DHA ratios or high DHA products.
While fish oil has been used for general health and wellness for many years, high EPA formulations are of particular interest due to research suggesting specific roles for EPA in certain biological processes. Regulatory bodies like the FDA have approved specific high-dose EPA formulations (e.g., icosapent ethyl) for certain medical conditions, demonstrating its pharmacological relevance beyond general supplementation.
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Known interactions
Category rule: glp1 × supplement
Note
GLP-1 medications slow stomach emptying, changing how/when oral supplements absorb; rapid weight loss raises the importance of protein and micronutrients.
Time oral supplements when nausea is lowest; prioritize protein and micronutrients; discuss with your provider.
Category rule: supplement × medication
Note
Some supplements change how the body processes medications (absorption, liver enzymes, or additive effects).
Specific pairs are checked against a licensed drug database and shown with their own severity. Always confirm with your provider or pharmacist.
Discuss with prescribing clinician; monitor for bruising, prolonged bleeding, and dose adjustments.
Frequently asked
Sources referenced
["NIH Office of Dietary Supplements (ODS)", "MedlinePlus - National Library of Medicine", "PubChem - National Center for Biotechnology Information", "Mayo Clinic", "U.S. Food and Drug Administration (FDA) Drug Labels", "Cochrane Library", "DrugBank"]
Stackwise compiles summaries from publicly available scientific and regulatory references. Always verify important decisions with a licensed clinician.
Related compounds
Others in the supplement category or studied for the same goals.