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.”
What is fish oil and what are the benefits of taking it?
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.
Best fish oil supplements at a glance
Best overall – Bare Biology life and soul high-strength omega-3 daily capsules: £28, Healf.com
Best budget buy – Inessa Advanced Omega-3: £24.99, Inessawellness.com
Best for easy taking – Wiley’s Finest Peak EPA: £26.50, Healf.com
Best for purists – Wild Nutrition Pure Strength Omega-3: £38, Wildnutrition.com
Best for travel – Reviveactive Omega Active - £24.95, Reviveactive.com
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.
Any downsides?
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.”
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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.
How do I take them and how often should I take them?
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.
Is there a fish liver oil alternative for vegetarians?
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.
How I tested
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.
Bare Biology Life and Soul High-Strength Omega-3 Daily Capsules
★★★★★
Best: Overall fish oil supplement
What we love: 5-star third-party verification, high-quality, and the presentation
Take note: Expensive
With 1,700mg of omega-3 sustainably sourced from small, wild-caught fish and a fish gelatine shell, these supplements secure the top spot for quality. The exact ratio works out at 1,100mg of EPA, 500mg of DHA and 100mg of other omega-3s including DPA.
The fish oil in each capsule is in triglyceride form, which is the most bioavailable form, and there’s no fishy smell or flavour. The glass jar is also tinted to protect the capsules inside from oxidation, which is a good sign. I took two a day after breakfast.
Other winning attributes include an IFOS 5-star rating on every batch – this is the gold standard for both purity and potency verification, not just contaminants – and sustainability certifications from Friend of the Sea and the Marin Trust.
The only downside is that these capsules are the most expensive; however, you can save 15 per cent when you subscribe.
Buy now £28.00, Healf.com
Inessa Advanced Omega-3
★★★★★
Best: Budget fish oil supplements
What we love: High-quality, great value for money, and IFOS 5-star certified
Take note: Sustainability credentials are less robust
I’ve been taking this particular fish oil for years, and it holds up very well against Bare Biology’s capsules, while being cheaper. With 1200mg of omega-3 oil split between 480mg EPA and 360mg DHA, the oil is also in triglyceride form for the best absorption and comes from small, wild fish.
The sustainability credentials are slightly less robust, with only one certification from Friend of the Sea; however, the brand boasts the same IFOS 5-star certification as Bare Biology so is verified as a gold standard. Inessa also uses a fish gelatin shell and adds vitamin E to prevent oxidation. In my view, it offers the best value per mg of EPA and DHA and has no unpleasant taste or smell.
The brand founder, who is a nutritionist herself, recommends dosing up or down depending on your needs. I usually take two, but I’m used to taking fish oil. You might want to start with one after a meal and then increase your dose if you feel you need to.
The packaging is tinted to protect the contents and is plastic, so it’s easy enough to throw in your bag without worrying about it breaking.
Buy now £24.99, Inessawellness.com
Wiley’s Finest Peak EPA
★★★★☆
Best: Fish oil supplements for easy taking
What we love: Mini softgel is easier to swallow, sustainably sourced, and MSC certified
Take note: Ethyl ester form, not triglyceride, so it is less naturally absorbed
I’ve also taken Wiley’s Finest fish oil for many years and recommend these mini capsules to everyone because they’re easy to swallow. Fish oil is great, but the capsules can often be huge, which is a dealbreaker if you struggle to swallow even regular-sized supplements.
These mini softgels are 55 per cent smaller than a regular capsule and contain a high-potency omega-3 blend of 360mg EPA and 270mg DHA contained in a fish gelatine shell. They’re MSC certified and UK-made using a sustainable model that uses byproduct-stream sourcing from Alaskan pollock. They’re also among the more affordable options on this list.
These capsules use an ethyl ester form of fish oil rather than triglycerides, which is generally regarded as less naturally absorbed; however, there isn’t yet conclusive evidence to substantiate this, and the brand is well respected as a leading fish oil manufacturer. If you’re concerned about this, the brand offers a Peak Omega-3 Liquid product – a liquid version of concentrated omega-3 triglycerides that you take with a teaspoon.
Buy now £26.50, Healf.com
Artah Essential Omegas
★★★★☆
Best: Fish oil supplement with added benefits
What we love: Triglyceride form, tinted glass jar, Friend of the Sea certified and has added vitamin E to prevent oxidation
Take note: Expensive and doesn’t publish its third-party testing results online
Sourced from sustainably sourced wild anchovies, one serving of Artah’s fish oil supplement delivers the equivalent of 1500mg of combined EPA and DHA – 1000mg EPA and 500mg DHA.
The supplement delivers omegas in triglyceride form with no fishy smell or taste and is certified by Friend of the Sea. As a B Corp, the brand has good sustainability credentials and having a nutritionist as a founder provides a little extra peace of mind too. The brand also confirms third-party testing for purity and freshness, though doesn’t publish its results online.
The supplements come in a tinted glass jar and boast added Vitamin E to prevent oxidisation, so they’re a strong option, though on the pricier end of the scale.
Buy now £32.00, Facethefuture.co.uk
Wild Nutrition Pure Strength Omega-3
★★★★☆
Best: For supplement purists
What we love: Tinted glass bottle, MSC-certified, B-Corp company, and Trigliceride form
Take note: Four capsules a day might be a lot for some
Also derived from sustainable Alaskan Pollock fish, four of Wild Nutrition’s capsules provide 800mg EPA and 400mg DHA. This brand is a great option for supplement purists who seek quality and don’t mind taking several pills, though it might be harder to swallow for those who don’t fancy taking four capsules to hit their daily dose before taking any other supplements.
The fish oil used is MSC certified, in triglyceride form and has been independently tested for toxins and heavy metals. Encased in a fish gelatin capsule, there’s no fishy taste or smell, and I didn’t experience any stomach issues when taking this supplement.
The brand is a B Corp company, which is a green flag for sustainability; however, it doesn’t include an IFOS or equivalent potency and freshness certification on its website. What I did love was the dark-tinted glass bottle, which protects the capsules from oxidisation and is easy to recycle.
Buy now £38.00, Wildnutrition.com
Reviveactive Omega Active
★★★★☆
Best: Fish oil supplement for travel
What we love: Plant-based shell, Friend of the Sea certified, and added vitamin E
Take note: No purity or potency testing listed
Reviveactive’s offering contains 1362mg of omega-3 fish oil with a ratio of 756mg EPA and 504mg DHA per two-capsule serving, so the dose is decent. Unlike the other options on this list, the brand uses a plant-based enteric coating, which supposedly reduces stress on the stomach by breaking down in the upper intestinal tract instead of the stomach.
I didn’t experience any fishy burps or nausea, so this could well be a plus. I also took the recommended dose of two capsules with food, so this would also have reduced any stomach issues.
The fish oil in each capsule is certified by Friend of the Sea, but there’s no independent purity or potency testing like IFOS disclosed for this product or any indication of whether the form is triglyceride or ethyl ester, so it’s a little harder to gauge the levels of what’s being delivered.
There is added vitamin E to prevent oxidisation, so this is a good sign. The capsules are also protected inside a blister pack and cardboard packaging, so would be much better for travel than some of the glass options on this list.
Buy now £24.95, Reviveactive.com
What are the best fish oil supplements?
These supplements are all strong contenders for purity, freshness and impact, but Bare Biology's Life and Soul takes the top spot here, ticking every box for dose, testing and type. It offers a clinically meaningful 1700mg dose in triglyceride form and an IFOS 5-star certification, which is the closest thing to an independently verified gold standard.
If you want the same quality for less, Inessa is the smarter buy, offering the same IFOS 5-star rating and triglyceride form. ARTAH sits in the middle ground with its strong dose and triglyceride form, but it doesn’t share its credentials, while Wiley's Finest is the one to reach for if swallowing capsules is an issue. Wild Nutrition and Revive Active serve more specific needs for pill-purists who don't mind a higher capsule count, or travellers looking for something that won't shatter in a suitcase.
Why trust me
I’ve been taking fish oil on and off for decades. This is a supplement that’s been around a long time and has gone through several updates based on emerging research so I’m well-versed in new data on omega-3s and how brands are using it. Having been a health and wellbeing journalist for more than a decade, I can separate a ridiculous claim from genuine science and have made it my mission to dispel wellness misinformation.
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