Krill Oil

Krill are small shrimp-like crustaceans, and Antarctic krill is among the most abundant animal species on the planet by biomass. Krill oil is extracted from the whole animal.

The distinguishing feature is chemical form. In fish oil, EPA and DHA are attached to a glycerol backbone as triglycerides. In krill oil, a substantial proportion is bound into phospholipids, the same molecular class that makes up cell membranes.

Krill oil also naturally contains astaxanthin, which gives it its red colour and provides some protection against the oil going rancid. The catch is concentration: krill oil typically supplies far less EPA and DHA per gram than a concentrated fish oil, which is the number that actually matters.

EPA and DHA do the same things regardless of how they arrive: incorporate into cell membranes, serve as substrates for the specialised mediators that resolve inflammation, and compete with omega-6 derived signalling.

The phospholipid form is proposed to absorb more efficiently, since phospholipids emulsify readily and do not require the same processing as triglycerides. Studies comparing the two have generally supported better absorption per milligram of EPA and DHA from krill.

Whether that advantage outweighs the much lower content per capsule is the actual question, and it is an arithmetic one rather than a biological one.

Trials comparing krill oil with fish oil have generally found comparable or slightly better increases in the omega-3 index per milligram of EPA and DHA delivered, supporting the absorption argument.

Outcome research on lipids and inflammatory markers shows broadly similar effects to fish oil when the omega-3 dose is matched.

The practical conclusion is arithmetic. A krill capsule might supply 60 mg of combined EPA and DHA against 500 mg or more from a concentrated fish oil capsule at similar or lower cost. Even allowing for better absorption, closing an eightfold gap is difficult, and for most people fish oil delivers more omega-3 per pound spent. Krill makes sense if you tolerate it better or want the phospholipid form specifically.

Krill oil is well tolerated, and notably better tolerated than fish oil for reflux and aftertaste, which is one of its genuine selling points.

Shellfish allergen declaration is mandatory and this is not optional caution — krill are crustaceans, and anyone with a shellfish allergy must avoid it entirely. Fish oil or algal oil are the alternatives.

As with any omega-3, high intakes modestly affect how readily blood clots. Speak to your doctor before use if you take anything affecting clotting, and stop high doses before surgery. Sustainability certification is worth checking given the ecological importance of krill.