Omega-3 and High Triglycerides: Evidence and Guideline Views
What research and the American Heart Association advisory say about omega-3 and high triglycerides, and how prescription products at 4 g a day differ from over-the-counter fish oil.
Content last updated . This page has not been medically reviewed.
Quick answer
Omega-3 (EPA and DHA) does lower blood triglycerides. A Cochrane review found a reduction of about 15%, rising with the amount taken. [1] At the very high amounts used in prescription products (4 g a day), an American Heart Association (AHA) science advisory describes reductions of 30% or more in people with very high triglycerides. [2] Lowering a lab number is not the same as preventing a heart attack, and a prescription result is not a result for over-the-counter fish oil. High triglycerides are managed by a clinician; this page is information only.
Terms used by the sources
- Triglycerides are a type of fat in the blood. NCCIH says excessive levels may raise the risk of heart disease. [3]
- Hypertriglyceridemia is the AHA advisory's term for triglycerides of 200 to 499 mg/dL. Very high means 500 mg/dL or higher. [2]
- US prescription labels use their own cut-offs: 150 mg/dL or higher for a heart-risk indication, and 500 mg/dL or higher for severe hypertriglyceridemia. [4]
- Units differ: US results are in mg/dL, and some countries use mmol/L. REDUCE-IT reports its entry range as 135 to 499 mg/dL (1.52 to 5.63 mmol/L). [5] Check the units on any report.
What the evidence found
| Question | What the source found | Strength of evidence |
|---|---|---|
| Do EPA and DHA lower triglycerides in general? | Cochrane 2020: about 15% reduction, dose-dependent; little or no effect on adiposity, other lipids or blood pressure. [1] | High certainty (Cochrane rating for this outcome) |
| Same, in a review of 23 studies? | NCCIH summarizing a 2020 review of 23 studies (43,998 people): about 15% lower, with no effect on body fat or other lipids. [3] | Review summary |
| Very high triglycerides at 4 g a day | AHA advisory: EPA plus DHA prescription products lower triglycerides by 30% or more, with increases in LDL cholesterol. EPA-only did not raise LDL cholesterol in very high triglycerides. [2] | Established for the lab number |
| Triglycerides 200 to 499 mg/dL | AHA advisory: EPA plus DHA or EPA-only appear roughly comparable for lowering and do not raise LDL cholesterol as monotherapy or with a statin. [2] | Established for the lab number |
| Fewer heart events with a purified EPA product | REDUCE-IT: 4 g a day icosapent ethyl, 17.2% vs 22.0% primary events (hazard ratio 0.75) in statin users with triglycerides 135 to 499 mg/dL. [5] The AHA advisory cites a 25% reduction in major adverse cardiovascular events. [2] | One prescription-product trial |
| Fewer heart events with EPA plus DHA at 4 g a day | STRENGTH vs corn oil: 12.0% vs 12.2% (hazard ratio 0.99); stopped early. [6] | No benefit shown |
| Over-the-counter fish oil for triglycerides | The AHA advisory abstract we read covers pharmacological doses of more than 3 g a day of EPA plus DHA. It does not describe over-the-counter products; not described in the sources we read. [2] | Proper evidence not found here |
What the AHA advisory concludes
The AHA advisory (Circulation, 2019) summarizes the lipid effects of pharmacological doses (more than 3 g a day total EPA plus DHA). It notes that a 2002 AHA statement had recommended 2 to 4 g a day for people with elevated triglycerides. Its conclusion: prescription omega-3 (EPA plus DHA, or EPA-only) at 4 g a day is "an effective and safe option" for reducing triglycerides alone or alongside other lipid-lowering medicines. [2] The advisory was published in 2019, and its abstract says results of a trial of 4 g a day of prescription EPA plus DHA in hypertriglyceridemia were anticipated in 2020. [2] The STRENGTH trial of an EPA and DHA product was published later, in 2020, and found no difference in cardiovascular events. [6]Prescription vs over-the-counter
Prescription labels list use with diet to lower triglycerides of 500 mg/dL or higher, and for icosapent ethyl also a heart-risk use with a statin. [4][7] The EPA and DHA label advises periodic triglyceride and LDL cholesterol checks and ALT/AST checks in liver impairment. [7] NCCIH notes prescription products differ in composition, testing and regulation from supplements. [3] A supplement label states "fish oil 1000 mg" but the EPA plus DHA inside is a smaller number: see EPA and DHA per serving and prescription vs supplement.Frequently asked questions
Does fish oil lower triglycerides?
EPA and DHA lowered triglycerides by about 15% in a Cochrane review, in a dose-dependent way. [1] That is an average across studies, not a promise for one person.
How much do prescription omega-3 products lower very high triglycerides?
The AHA advisory says 4 g a day of EPA plus DHA prescription agents reduced triglycerides by 30% or more in very high triglycerides, with increases in LDL cholesterol. [2]
Does lowering triglycerides with omega-3 prevent heart attacks?
Not by itself. REDUCE-IT (purified EPA, 4 g a day) reduced events, while STRENGTH (EPA plus DHA, 4 g a day) did not. [5][6]
Is over-the-counter fish oil as good as the prescription?
NCCIH says prescription effects may not be the same as supplements. [3] A head-to-head comparison is not described in the sources we read.
Can omega-3 raise LDL cholesterol?
The AHA advisory says EPA plus DHA agents at 4 g a day increased LDL cholesterol in very high triglycerides, while EPA-only did not. [2] Ask your clinician how your LDL is monitored.
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Limits and uncertainty
- The 15% figure is an average across trials with different products, amounts and people; it does not predict one person's result.
- The AHA advisory covers prescription products; it does not tell readers to use supplements for high triglycerides, as far as the abstract we read states.
- Lifestyle changes such as diet, weight control and exercise are used to lower triglycerides, and some people also need medicine. [3] The prescribing information tells prescribers to identify other causes of high triglycerides, such as diabetes, hypothyroidism or medications, and manage them. [7]
Safety and who should ask a clinician
High or very high triglycerides need a clinician's assessment and plan. Do not self-treat with fish oil in place of prescribed treatment, and do not stop a prescribed medicine on your own. Both prescription labels warn about fish and shellfish allergy, bleeding with antithrombotic medicines (icosapent ethyl) and atrial fibrillation or flutter. [4][7] Tell your surgeon about omega-3 before an operation. Ask a pharmacist about interactions; see medication interactions, blood-pressure and cholesterol effects and omega-3 safety.
References
- Abdelhamid AS et al. Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev 2020. Read 2026-10-23.
- Skulas-Ray AC et al. Omega-3 fatty acids for the management of hypertriglyceridemia: a science advisory from the American Heart Association. Circulation 2019. Read 2026-10-23.
- NCCIH, Omega-3 Supplements: What You Need To Know. Read 2026-10-23.
- FDA-approved prescribing information for icosapent ethyl capsules (Vascepa), label revised 3/2026, DailyMed. Read 2026-10-23.
- Bhatt DL et al. Cardiovascular risk reduction with icosapent ethyl for hypertriglyceridemia (REDUCE-IT). N Engl J Med 2019. Read 2026-10-23.
- Nicholls SJ et al. Effect of high-dose omega-3 fatty acids vs corn oil on major adverse cardiovascular events in patients at high cardiovascular risk (STRENGTH). JAMA 2020. Read 2026-10-23.
- FDA-approved prescribing information for omega-3-acid ethyl esters (Lovaza), DailyMed. Read 2026-10-23.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.