Best Omega-3 Fish Oil Supplements UK (2026)
Most UK adults are chronically under-consuming omega-3 fatty acids. Here's what to look for in a fish oil supplement, and our top recommended products.
The one number that matters: EPA+DHA combined
Most fish oil marketing focuses on the total fish oil content per capsule — 1000mg, 2000mg, etc. This number is almost meaningless. What matters is the combined EPA (eicosapentaenoic acid) + DHA (docosahexaenoic acid) content. Aim for at least 500mg combined EPA+DHA per serving for a maintenance dose.
What to look for
EPA+DHA content clearly stated on the label (not just "fish oil")
IFOS certification or equivalent for purity and freshness
Molecular distillation mentioned — removes mercury and PCBs
Triglyceride form preferred over ethyl ester for absorption
Best-before date checked — fish oil oxidises over time
Fish oil vs algae oil: which is better?
Fish oil and algae oil provide the same omega-3 fatty acids (EPA and DHA). Fish get their omega-3s from algae in the first place. Algae oil is more environmentally sustainable and suitable for vegans, and is increasingly available at competitive prices. Both are valid choices — pick based on your dietary preferences and budget.
Signs your fish oil has gone bad
Rancid fish oil is worse than no fish oil — oxidised fatty acids may actually be harmful. Signs of rancidity include an extremely fishy smell (fresh fish oil should smell mild), a strong fishy aftertaste hours after taking it, and a yellow-brown colour rather than pale golden. Store in the fridge after opening.
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