Best Omega-3 Supplements: What a Cardiologist Looks For

Medically reviewed by Dr. Don Zone, MD, FACC, FAARM — Board-Certified Cardiologist · Updated September 2026

The Short Answer

The best omega-3 supplement gives you at least 500 mg of combined EPA and DHA per serving, comes in triglyceride form, and has published third-party results for purity and oxidation (IFOS or an equivalent program). After that, choose the EPA-to-DHA ratio for your goal. EPA-heavy formulas suit heart and mood goals. DHA-heavy formulas suit pregnancy, eyes and the brain. The number on the front of the bottle (“1,000 mg fish oil”) matters much less than the EPA and DHA numbers on the back. I’m a cardiologist, so I’ll say this plainly: omega-3s are not a substitute for a statin, blood-pressure control or not smoking. Some people do benefit from them, and product quality varies a lot. This guide covers the five things I check before I recommend any fish oil.

Why Most People Fall Short on Omega-3s

EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) are long-chain omega-3 fats found mainly in fatty fish. Your body can make a little of them from the ALA in flax, chia and walnuts, but the conversion is inefficient. For practical purposes, you need EPA and DHA from fish, algae or a supplement. The American Heart Association recommends one to two servings of seafood per week for the general population. Most Americans don’t get that. If you don’t eat salmon, sardines, mackerel or herring at least twice a week, a supplement is a reasonable way to close the gap. A good test for whether you’re actually short is the Omega-3 Index, a simple blood test that measures EPA plus DHA as a percentage of red blood cell fats. Researchers proposed a target of 8% or higher, with under 4% linked to the highest cardiovascular risk (Harris & von Schacky, Preventive Medicine, 2004). I like it because it shows what your body actually absorbed, which a label can’t tell you.

EPA vs DHA: Which Ratio Should You Look For?

EPA and DHA usually come together, but they do different jobs. EPA is the omega-3 with the best cardiovascular evidence at high doses. In the REDUCE-IT trial, 4 g/day of prescription purified EPA (icosapent ethyl) cut major cardiovascular events by 25% in 8,179 high-risk patients already on statins (Bhatt et al., NEJM, 2019). EPA-dominant formulas also have the best evidence for mood. A meta-analysis found benefit for depressive symptoms mainly with formulas that were at least 60% EPA, at about 1 g EPA per day (Liao et al., Translational Psychiatry, 2019). DHA is a structural fat. It’s highly concentrated in the brain and retina, and it’s the omega-3 that matters most during pregnancy and breastfeeding for fetal brain and eye development. What ratio to look for:

• Heart health, triglycerides, mood: EPA-dominant, around 2:1 to 3:2 EPA:DHA.
• Pregnancy, breastfeeding, vision, general brain support: a DHA-dominant or balanced formula (1:1, or DHA-forward).
• General health if you rarely eat fish: a balanced formula is fine. Total EPA+DHA matters more than the exact ratio.

One honest caveat: the positive REDUCE-IT result came from a prescription, purified EPA drug at 4 g/day. The STRENGTH trial gave a similar-risk population 4 g/day of a combined EPA+DHA product and was stopped early for lack of benefit (Nicholls et al., JAMA, 2020). No over-the-counter fish oil has reproduced REDUCE-IT, so be skeptical of any label that suggests otherwise.

Triglyceride vs Ethyl Ester: Why Form Matters

This is the detail most shoppers never check, and it affects both absorption and price. Fish oil starts in natural triglyceride (TG) form. To concentrate it, manufacturers usually convert it to ethyl ester (EE) form. Some then convert it back into a re-esterified triglyceride (rTG). EE concentrates are cheaper to make, and that’s why so many budget brands use them. The absorption difference is real. In a head-to-head trial, rTG fish oil had 124% of the bioavailability of natural fish oil, while ethyl esters came in at 73% (Dyerberg et al., Prostaglandins, Leukotrienes and Essential Fatty Acids, 2010). A larger six-month trial of 150 people found that the triglyceride form raised the red blood cell Omega-3 Index significantly more than the same dose as ethyl esters (Neubronner et al., European Journal of Clinical Nutrition, 2011). Ethyl esters absorb poorly on an empty stomach and much better with a meal that contains fat. So if you already own an EE product, take it with your largest meal. How to tell which form you’re buying: Look for “triglyceride form,” “rTG” or “natural triglyceride” on the label. If the label doesn’t state the form, assume it’s an ethyl ester. Manufacturers who use the more expensive TG form almost always say so.

Purity and Oxidation Testing: IFOS and Equivalents

A fish oil can be clean and still spoiled. Those are two separate tests, and you want a product that passes both. Purity means low levels of mercury and other heavy metals, PCBs and dioxins. Molecular distillation removes most of these, and reputable brands test every batch. Oxidation means rancidity. Omega-3s are fragile fats, and heat, light and time break them down. Oxidized oil smells fishy, causes more “fish burps,” and may not deliver the benefits you’re paying for. The industry standard is the GOED Voluntary Monograph, which sets these maximum limits:

• Peroxide value (PV): ≤5 meq/kg (early-stage oxidation)
• Anisidine value (AV): ≤20 (later-stage oxidation)
• TOTOX: ≤26 (total oxidation, 2×PV + AV)

In Consumer Reports’ April 2026 testing of 20 popular fish oil supplements, 11 met its quality standards, 5 couldn’t be fully assessed for rancidity, and 4 failed. Some products also contained less omega-3 than their labels claimed. None raised major heavy-metal or dioxin concerns. Contamination is rarely the problem today. Freshness and label accuracy are. Third-party programs worth looking for: My at-home test: Cut open a capsule and smell it. Fresh fish oil smells mild, like the ocean. A sharp, paint-like or strongly fishy smell means it’s oxidized, so throw it out. Store your bottle away from heat, and refrigerate it after opening if the label allows.

Omega-3 Dose by Goal

The FDA considers supplements providing up to 5 g/day of EPA plus DHA safe when used as directed, and the European Food Safety Authority reached the same conclusion. Most people need far less than that. These are the evidence-based ranges I use: Safety notes from a cardiologist:

• Atrial fibrillation. Both REDUCE-IT and STRENGTH saw more atrial fibrillation at 4 g/day, and a 2021 meta-analysis found the risk rose mainly at doses above 1 g/day (Gencer et al., Circulation, 2021). If you have AFib or palpitations, talk to your cardiologist before taking high-dose fish oil.
• Blood thinners. Omega-3s have mild antiplatelet effects. Studies of 3–6 g/day fish oil haven’t shown a significant change in warfarin’s effect, but I still want patients on anticoagulants to tell their doctor before starting.
• Take it with food. A meal that contains fat improves absorption and reduces fishy aftertaste.
• Retest. Check your Omega-3 Index about three to four months after starting, because that’s how long red blood cells take to turn over.

Not every claim holds up. In the DREAM trial, 3 g/day of omega-3s did no better than an olive-oil placebo for dry eye disease (NEJM, 2018). I’d rather you spend your money where the evidence is.

Omega-3 Supplement Comparison: Forms at a Glance

What I Recommend: ProOmega 3.6.9

When patients ask which omega-3 I carry, it’s ProOmega 3.6.9 by Nordic Naturals. It meets every criterion above:

• 1,170 mg EPA + DHA per 2-softgel serving (780 mg EPA, 390 mg DHA): a 2:1 EPA-dominant ratio for heart health, and about 1 g/day in a single serving
• Triglyceride form, the better-absorbed form
• Every batch third-party tested for heavy metals, dioxins and PCBs
• Small amounts of GLA and omega-9 (76 mg GLA, 120 mg oleic acid). GLA is an omega-6 with anti-inflammatory properties. You don’t need extra omega-6 from other sources, and I explain why in omega 3, 6 and 9 compared
• Natural lemon flavor and rosemary extract as a natural antioxidant, 120 softgels (a 60-day supply at 2 per day)

For a complete cardiovascular protocol, including CoQ10 and the other nutrients I use with patients, see my heart health supplement protocols.

Frequently Asked Questions

What is the best form of omega-3 to take?

Triglyceride form (natural or re-esterified) absorbs better than ethyl ester form, especially if you take it without food. If you can’t take fish oil, algal oil is the best vegan option for DHA.

How much omega-3 should I take a day?

For general health, 250–500 mg of combined EPA and DHA. People with coronary heart disease are typically advised to get about 1,000 mg. Doses above 1 g/day should be discussed with your doctor because of atrial fibrillation risk.

Is fish oil the same as omega-3?

No. “Fish oil” is the whole oil. EPA and DHA are the active omega-3s in it. A 1,000 mg fish oil capsule may contain only 300 mg of EPA+DHA, so always read the EPA and DHA values.

Which is better, EPA or DHA?

Neither. They have different jobs. EPA has stronger evidence for triglycerides, cardiovascular events and mood. DHA matters most for the brain, eyes and pregnancy. Most adults do well with an EPA-dominant blend.

Is the best omega-3 supplement different for women and men?

The quality criteria are the same. Women who are pregnant, breastfeeding or planning pregnancy should prioritize DHA (at least 200 mg/day). Men focused on heart health or triglycerides generally benefit from an EPA-dominant formula.

When is the best time to take omega-3?

With your largest meal of the day, ideally one that contains fat. Timing matters less than taking it consistently.

Key Takeaways

• Read the EPA + DHA numbers, not the “fish oil” total. Aim for at least 500 mg per serving.
• Choose triglyceride form. In head-to-head testing, ethyl esters delivered about 40% less than rTG.
• Demand oxidation testing (TOTOX ≤26) along with heavy-metal testing. IFOS, USP and NSF are the main programs.
• Match the ratio to your goal: EPA-dominant for heart and mood, DHA-forward for pregnancy and brain.
• Doses above 1 g/day are where atrial fibrillation risk appeared in trials. If you have AFib or take blood thinners, involve your doctor.
• Check your Omega-3 Index (target ≥8%) to confirm the supplement is working.

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Disclosure: Anti-Aging Today sells ProOmega 3.6.9, and Dr. Zone has a financial interest in products sold on this site. This article is for educational purposes and is not medical advice. Talk to your physician before starting any supplement, especially if you take blood thinners, have atrial fibrillation or are pregnant.

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