How much EPA and DHA should I take per day?

The European Food Safety Authority sets a general target of 250 mg a day of EPA plus DHA for adults. In pooled trials, an average of about 2 g a day raised the omega-3 index from about 5% to 8% over roughly 3 months. Higher doses should be discussed with a clinician.

What is the omega-3 index?

It is the share of EPA plus DHA in red blood cell membranes. Researchers proposed 8% or higher as a target and 4% or lower as a risk marker, based on observational studies. A higher index has not been proven to prevent disease in trials.

Does fish oil prevent heart attacks?

This page makes no such claim. In the VITAL trial of 25,871 older US adults, 1 g a day did not significantly reduce the main measure of major cardiovascular events. Anyone with heart disease or high triglycerides should follow their clinician's advice.

Is there a downside to high doses?

A 2021 meta-analysis of large trials linked omega-3 supplements to a higher risk of atrial fibrillation, especially above 1 g a day. Fish oil can also cause digestive side effects and may interact with blood thinners.

Should I take fish oil with food?

Yes. Absorption is better with a meal that contains fat, especially for ethyl ester products.

Should I keep fish oil in the fridge?

Rhonda Patrick recommends it because omega-3s oxidize easily. A test of 32 products in New Zealand found half exceeded recommended total oxidation levels.

Is eating fish better than supplements?

Health advisories recommend one to two servings of seafood a week. Food brings other nutrients, but supplements are an option if you rarely eat oily fish.

How Much Omega-3 Fish Oil Should You Take? EPA and DHA Doses, Testing and Evidence

There is no single right dose. General recommendations for adults start around 250 mg of EPA plus DHA a day. Studies aiming for a higher omega-3 index used more: in pooled data from 14 trials, an average of about 2 g a day raised the index from about 5% to 8% in roughly three months. Large trials have not shown that supplements prevent heart disease in the general population, and high doses carry a small atrial fibrillation risk.

This page is general information, not medical advice. It makes no claims about preventing or treating disease. Fish oil can interact with blood thinners; check with a clinician before high doses, if you have a heart rhythm problem, or if you are pregnant.

Dose options at a glance

Approach	EPA + DHA per day	Source
European (EFSA) adult recommendation	About 250 mg	NIH Office of Dietary Supplements
Average dose that raised the index to about 8%	About 2 g (1,983 mg)	Walker et al., 2019
Rhonda Patrick’s suggested threshold	2 g	Huberman Lab
Upper level FDA considers safe from supplements	No more than 5 g	NIH fact sheet

The NIH notes that EFSA’s figure for adults is 250 mg a day of EPA plus DHA, with an extra 100–200 mg of DHA during pregnancy.

The omega-3 index

The omega-3 index is the percentage of EPA plus DHA in red blood cell membranes, measured with a finger-prick or blood test. Harris and von Schacky (2004) proposed it as a heart risk marker: in their analysis, an index of 8% or more went with the lowest risk of death from coronary heart disease and 4% or less with the highest.

A 2017 analysis of 10 cohort studies found an average index of 6.1%, with the lowest fifth of people around 4.2% and the highest around 8.3%. Each 1-standard-deviation increase was associated with a 15% lower risk of fatal coronary heart disease. These are associations in observational data, not proof that raising your index changes your risk.

How much does a given dose raise it?

The 2019 pooled analysis used data from 1,422 people in 14 trials:

Average response: people taking a mean of 1,983 mg a day for about 13.6 weeks went from 4.9% to 8.1%.
What predicts response: only the starting index, the dose and the chemical form mattered; together they explained 62% of the variation.
Lower dose: the model predicted about 6.5% for 850 mg a day of an ethyl ester product, starting from 4.9%.
Form: gram for gram, triglyceride products raised the index by about 1 percentage point more than ethyl esters. See triglyceride vs ethyl ester.

Because responses vary, testing before and about 3 months after a change is the only way to know your own number.

What large trials found

Trial or review	Who	Finding
VITAL, 2019	25,871 US adults aged 50+ (men) or 55+ (women), 1 g/day, median 5.3 years	No significant reduction in the main composite of major cardiovascular events or in invasive cancer
Atrial fibrillation meta-analysis, 2021	7 trials, 81,210 patients	Supplements linked to a 25% higher risk of atrial fibrillation; higher with doses above 1 g/day
Mood meta-analysis, 2024	67 trials	Did not reduce the risk of developing depression in the general population; effects in people with diagnosed depression are a clinical question beyond this page

VITAL tested a moderate dose in people at usual risk. Its main result was null, even though some secondary outcomes differed. That is why this page treats the omega-3 index as a marker of intake, not as a proven way to prevent disease.

The atrial fibrillation finding matters for anyone considering high doses. In the 2021 meta-analysis, the hazard ratio was 1.49 in trials testing more than 1 g a day, compared with 1.12 in trials testing 1 g or less.

What Rhonda Patrick says

On the Huberman Lab episode, Patrick says “I think two grams is a good threshold” and that she personally takes four grams a day. She checks International Fish Oil Standards testing for contaminants and oxidation, aiming for a total oxidation (TOTOX) value under 10, ideally under 6, and urges: “please keep your fish oil in the refrigerator.” Her dose is higher than general recommendations; the atrial fibrillation data above are a reason to discuss doses above 1 g a day with a clinician.

Quality and storage

A 2015 test of 32 fish oil products in New Zealand found that 69% contained less than two-thirds of the labelled EPA and DHA, and half exceeded recommended total oxidation levels. Price and best-before date did not predict quality.

Check the label: count EPA plus DHA per serving, not total fish oil.
Look for third-party testing of content, contaminants and oxidation.
Store cool and closed; discard oil that smells strongly rancid.
Take with a meal containing fat.

Safety and interactions

The NIH fact sheet lists common side effects as unpleasant taste, bad breath, heartburn, nausea, digestive discomfort, diarrhea and headache. Fish oil may prolong clotting times with warfarin, although most research found doses of 3–6 g a day did not significantly change anticoagulation; people on blood thinners should be monitored by their clinician. The FDA has concluded that supplements providing no more than 5 g a day of EPA and DHA are safe when used as recommended.

Food first?

Health advisories cited by the NIH recommend one to two servings of seafood a week. If you eat oily fish regularly, you may already reach general targets. Supplements make the most sense if you rarely eat fish or want a specific index; for related blood tests, see metabolic health biomarkers, and for the wider picture, the evidence-based supplements guide.