How to Choose the Best Omega-3 Supplement: What the Labels Don't Tell You

Omega-3 supplements range from a few euro to well over forty, and the labels don't make comparison easy. "1,000 mg fish oil" can mean very different amounts of the omega-3s you're actually buying it for.

This guide explains what to check on the label, which details genuinely matter, and which ones you can ignore.

Why people take omega-3

The two important long-chain omega-3s are EPA and DHA. EPA and DHA contribute to the normal function of the heart, with a beneficial effect at a daily intake of 250 mg. DHA contributes to the maintenance of normal brain function and normal vision, also at 250 mg a day.

The best food sources are oily fish such as salmon, mackerel, sardines, herring and trout. Health bodies generally suggest eating oily fish about once or twice a week. Many people in Ireland and the UK eat less than that, which is why omega-3 is such a common supplement.

Plant foods such as flaxseed, chia and walnuts provide a different omega-3 called ALA. The body converts only a small amount of ALA into EPA and even less into DHA.

1. Check the EPA and DHA, not the fish oil

This is the single most useful thing to look at. A capsule labelled "1,000 mg fish oil" might contain 300 mg of EPA and DHA combined, or it might contain 600 mg or more. Look for the EPA and DHA figures in the nutrition panel and add them together, then compare that number across products.

Also check the serving size: some products list figures per two or three capsules.

2. Purity: look for molecular distillation and testing

Fish can accumulate contaminants such as mercury, PCBs and dioxins. Reputable fish oils are refined, commonly by molecular distillation, to remove them, and are tested against limits set in EU law. Look for statements about purification and testing; independent certification schemes such as IFOS publish batch results.

Fish oils from small fish lower in the food chain, such as anchovies and sardines, tend to start with fewer contaminants.

3. Freshness and oxidation

Omega-3 fats are delicate and can oxidise when exposed to heat, light and air. Signs of an oxidised product include a strong, rancid fishy smell or taste. Good manufacturers protect the oil with antioxidants such as vitamin E and test for oxidation.

• Store your omega-3 somewhere cool and dark, and keep the lid tight.
• Bite a capsule occasionally: a mild taste is normal, a sharp rancid one isn't.
• Use it before the best-before date.

4. The form: triglyceride vs ethyl ester

Fish naturally store omega-3 as triglycerides. During concentration, many oils are converted to ethyl esters (EE). Some are converted back to triglycerides (rTG). Studies suggest triglyceride forms are absorbed somewhat better than ethyl esters, especially when taken without food. Taking any fish oil with a meal containing fat narrows the difference considerably.

So form is a minor factor. Taking your omega-3 with a meal matters more.

5. Watch what else is in it

Some omega-3 products include other nutrients, such as vitamin D, K2 or vitamin A (common in cod liver oil). That can be convenient, but add up your total intake across all supplements. If you already take a separate vitamin D, you may not need more from your fish oil, and vitamin A should be avoided in high amounts during pregnancy.

6. If you don't eat fish

Algae oil provides EPA and DHA directly from the microalgae fish get theirs from. It suits vegetarians and vegans and is free from fish-derived contaminants.

How much and how to take it

• For general health, many people aim for at least 250 to 500 mg of EPA and DHA combined a day, roughly what oily fish twice a week provides.
• EFSA considers combined intakes of up to 5 g a day of EPA and DHA safe for adults.
• Take it with a meal to improve absorption and reduce fishy burps. Keeping capsules in the fridge helps some people with this too.

Who should check first

• People taking anticoagulants or antiplatelet medicines, as high doses of omega-3 may add to their effect.
• Anyone with a fish or shellfish allergy.
• Anyone who is pregnant or breastfeeding, especially before choosing a product that contains vitamin A or added vitamins.
• Anyone scheduled for surgery, or taking prescribed medicines.

Key takeaways

• Compare the EPA plus DHA content per serving, not the total fish oil.
• Choose a purified, tested product, and check it isn't rancid.
• Triglyceride forms may be absorbed slightly better, but taking omega-3 with a meal matters more.
• Count any added vitamins D, K or A against your total intake.
• Algae oil is the option for people who don't eat fish.

Our NeuroThrive™ Premium Omega-3 provides 330 mg EPA and 220 mg DHA per softgel in molecularly distilled fish oil, with vitamin D3, K2 and vitamin E. If you already take a separate vitamin D, count both towards your total.

Food supplements should not be used as a substitute for a varied and balanced diet and a healthy lifestyle. This article is for general information and is not medical advice.