Omega-3, Blood Pressure and Cholesterol: What Trials Show
What meta-analyses and an American Heart Association advisory found for omega-3, blood pressure, triglycerides, LDL and HDL cholesterol, and why the product matters.
Content last updated . This page has not been medically reviewed.
In pooled randomized trials, EPA plus DHA lowered blood pressure by a small amount on average, with larger changes in people with untreated high blood pressure. [1] Triglycerides fell by roughly 15 percent in a Cochrane review and by more in prescription-strength trials. [2] [3] LDL ("bad") cholesterol may rise with some DHA-containing products. [4] These are lab and blood pressure measurements, not heart attacks or strokes, so they do not on their own show a lower chance of heart disease. This page is information, not advice, and a clinician decides what is right for a person.
How to read the labels
"Modest" means the average change was small. "Mixed" means results differ by product or group. A change in blood pressure or cholesterol is a biomarker or surrogate result, not a clinical outcome. All amounts below are amounts used in studies, not recommendations.
Blood pressure
| Question | What the source found | Strength |
|---|---|---|
| Do EPA plus DHA change blood pressure? | In a meta-analysis of 70 trials, compared with placebo, systolic pressure fell 1.52 mm Hg and diastolic 0.99 mm Hg on average. [1] | Modest, pooled randomized trials |
| Who changed most? | Untreated hypertensive subjects: systolic pressure -4.51 mm Hg; normotensive subjects: -1.25 mm Hg. [1] | Subgroup finding |
| Does the amount matter? | A 2022 dose-response analysis of 71 trials (4,973 people) found J-shaped curves, with the largest average reductions between 2 g and 3 g per day of combined EPA and DHA. [5] | Suggestive; compares trials |
The 2014 analysis set no upper dose limit and included food sources. [1] Both report average changes in groups, not what any one person will see. Neither measured heart attacks or strokes.
Triglycerides
- A Cochrane review of long-chain omega-3 trials lasting at least 12 months found that EPA and DHA reduced triglycerides by about 15% in a dose-dependent way (high-quality evidence). [2] NCCIH describes the same size of effect. [6]
- An American Heart Association advisory said that, at prescription doses of 4 g per day, EPA plus DHA agents lowered very high triglycerides by 30% or more. [3]
- NCCIH notes that prescription products are approved for very high triglycerides and are not the same as supplements. [6] See prescription omega-3 vs supplements.
LDL and HDL cholesterol
- The AHA advisory reported that EPA plus DHA agents raised LDL in very high triglycerides, while EPA-only did not. [3]
- A meta-analysis of single-ingredient trials found that, compared with placebo, DHA raised LDL by 7.23 mg/dL, whereas EPA non-significantly reduced it. [4] DHA also raised HDL by 4.49 mg/dL; EPA did not. [4] The authors said more research was needed on what these differences mean. [4]
- The Cochrane review found no evidence that long-chain omega-3 changed lipids apart from triglycerides. [2] Reviews that pool different products and durations can differ.
So LDL results depend on the product (EPA only, DHA only, or both) and the population. We did not find a source that settles what an LDL rise means for health outcomes. Proper evidence not found: none of the sources we read link the LDL change from omega-3 to heart outcomes.
What this does not show
- Blood pressure and triglyceride changes do not guarantee fewer heart events. The Cochrane review found little or no effect of increasing EPA and DHA on cardiovascular events overall. [2] Details are on omega-3 evidence by use.
- Results from a purified EPA drug cannot be assumed for a fish oil capsule, or the reverse.
- Food, weight, activity and medicines also affect blood pressure and lipids; a clinician reviews the whole picture. See eating patterns compared.
Frequently asked questions
Does fish oil lower blood pressure?
On average a little. A meta-analysis of 70 trials reported about 1.5 mm Hg lower systolic pressure than placebo. [1] The effect was larger in people with untreated high blood pressure. [1]
Does omega-3 raise LDL cholesterol?
It can with some products. DHA raised LDL in a meta-analysis of single-ingredient trials, while EPA did not significantly. [4]
Does omega-3 lower triglycerides?
Yes, by about 15% in a Cochrane review of long trials. [2] Very high levels are treated with prescription products under a clinician. [3]
Can omega-3 replace blood pressure or cholesterol medicine?
The sources do not say so. Never stop a prescribed medicine without your prescriber.
Is a bigger amount better for blood pressure?
The dose-response analysis found a J-shaped curve, with the largest average effect between 2 g and 3 g per day in trials. [5] Those are study amounts, not advice, and higher amounts carry other risks.
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.
Safety and who should ask first
- Omega-3 products can interact with blood pressure medicines, blood thinners and other medicines. Ask a pharmacist: medication interactions.
- Do not stop or change a prescribed blood pressure, cholesterol or triglyceride medicine without your prescriber.
- Side effects in the sources include taste, bad breath, headache and stomach symptoms. [6] Atrial fibrillation risk at high amounts is covered on fish oil and atrial fibrillation.
- Check pregnancy, bleeding disorders and surgery plans with a clinician: supplements before surgery.
References
- Long-chain omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid and blood pressure: a meta-analysis of randomized controlled trials. Am J Hypertens 2014. Read 2026-10-22.
- Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev 2018. Read 2026-10-22.
- 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 2026-10-22.
- Effects of eicosapentaenoic acid versus docosahexaenoic acid on serum lipids: a systematic review and meta-analysis. Curr Atheroscler Rep 2011. Read 2026-10-22.
- Omega-3 polyunsaturated fatty acids intake and blood pressure: a dose-response meta-analysis of randomized controlled trials. J Am Heart Assoc 2022. Read 2026-10-22.
- National Center for Complementary and Integrative Health (US), Omega-3 Supplements: What You Need to Know. Last updated November 2024. Read 2026-10-22.