Best Omega-3 and fish oil supplements 2026, expert-tested

We’ve long been told that a healthy diet should contain oily fish like salmon, sardines, mackerel and trout, but very few people actually manage two portions a week – this is where the best fish oil supplements come in.

These yellow capsules contain the omega-3s needed for sound heart and brain health. However, they come in a range of strengths and ratios, with some far more sustainable, pure and effective than others.

“Fish oil provides EPA and DHA, the two long-chain omega-3s most linked to heart health, healthy triglyceride levels and brain cell membrane structure,” explains registered nutritionist Karen Preece Smith. “DHA is a major structural fat in brain cell membranes, so it’s essential, not optional.”

The best fish oil supplements tend to use wild anchovy, Alaskan pollock, sardine and mackerel and come in many formulations with differing ratios of EPA and DHA. Our bodies don’t make these naturally, so a daily supplement can contribute to healthy body and brain function.

The benefits of fish oil have been indicated across many recent studies, particularly in high-risk populations with cardiovascular and metabolic issues. The more general benefits are improved heart health, eye health and brain health, along with decreased inflammation, and research into the efficacy of omega-3 supplements is still developing.

For assured quality, Preece Smith recommends looking for EPA and DHA amounts stated per capsule, not just total fish oil weight; third-party testing such as IFOS and dark, airtight packaging with an added antioxidant like vitamin E.

Quality really matters with fish oil because omega-3 fats are delicate. Registered nutritionist Rhiannon Lambert explains that, “they are prone to oxidation, which is essentially the process of fats becoming rancid. When oils oxidise, the active fats EPA and DHA can be reduced, and the supplement may not contain what the label suggests. Pay attention to the brand’s testing, freshness and transparency rather than being drawn in by a glossy label or a huge ‘high strength’ claim.”

Sustainability is also a concern with fish oil supplements. “I’d want to know where it has come from, whether the brand is sourcing responsibly, and whether they have any sustainability certification or clear sourcing information,” says Lambert.

“Also look for third-party testing, batch testing, sustainability information and clear storage instructions. Ideally, the brand should be able to talk about oxidation testing, contaminants and heavy metals, rather than just making vague claims about purity. Fish oil is one supplement where I wouldn’t just buy the cheapest option in the biggest tub and assume it’s doing the job.”

Preece Smith adds that the supplement industry uses peroxide and TOTOX values to measure oxidation, and surveys have found that a meaningful proportion of commercial fish oils exceed the recommended limits. “I’d want to see those numbers published, not assumed,” she says.

Fish oil supplements are very well tolerated if they’re high quality and haven’t oxidised. If they have, you might be at risk of stomach issues, fishy burps and nausea. Brands will recommend a dose of one to four capsules per day, depending on the ratios inside a capsule – and the beauty of a capsule is no fishy taste.

Preece Smith advises that anyone on blood thinners or anticoagulant medication, or approaching surgery, should speak to their GP before taking fish oil. “I’d also flag caution for anyone with a fish or shellfish allergy, and would generally advise staying under 2g to 3g a day without medical supervision,” she adds.

Generally, experts advise taking fish oil capsules with a meal because omega-3s are fat-soluble nutrients that are absorbed much more effectively alongside food. For best results, healthy fats like avocados, nuts and eggs can help with optimal absorption and can also stave off any side effects such as nausea or acid reflux.

If you’re in perimenopause or older, new research suggests that splitting your dose across the day can help reduce inflammation markers. So you might consider taking one capsule with lunch and one with your dinner.

Yes, absolutely! There are lots of vegan supplements on the market which are suitable for both vegetarians and vegans, which only contain ALA (alpha-linolenic acid). ALA is one of the three key types of omega-3 fats, and can be found in plant-based foods such as nuts and flax; however, I would say that ALA doesn’t do as much as EPA or DHA on its own.

Therefore, it’s really important if you’re vegan to choose an alternative supplement which is made from marine algae. This is far better for the oceans and for the planet, offers the same health benefits, and helps you to avoid the risk of those potentially harmful heavy metals and toxins found in some fish oil pills.

I’ve tested many of the products on this list for several years, though some I’ve tested for the past few months. I looked for third-party testing and published TOTOX or peroxide values, along with the ratio of DHA to EPA. Sustainability is a very important indicator of quality when it comes to fish oil, so I looked for credible sources to verify each brand’s claims.