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Types of Fish Oil: Forms & Bioavailability

Reviewed by·PharmD, BCPS

This content is for informational purposes only and does not constitute medical advice. Consult your healthcare provider before starting any supplement. Full disclaimer

Forms Comparison

FormBioavailabilityBest For
Triglyceride Form (rTG)HighOptimal absorption — re-esterified triglyceride form is 70% better absorbed than ethyl esters; the gold standard for consumer fish oil supplements
Ethyl Ester Form (EE)ModerateConcentrated EPA/DHA per capsule — allows higher potency but lower bioavailability; must be taken with a high-fat meal; form used in most clinical trials including REDUCE-IT
Liquid Fish OilHighHigh-dose supplementation without swallowing multiple capsules — flavored versions mask taste; allows precise dose titration
Enteric-Coated SoftgelsHighEliminating fishy burps — coating prevents capsule dissolution in the stomach, releasing omega-3s in the small intestine instead; slightly delayed absorption

Triglyceride Form (rTG)

Bioavailability: High. Best for: Optimal absorption — re-esterified triglyceride form is 70% better absorbed than ethyl esters; the gold standard for consumer fish oil supplements.

Ethyl Ester Form (EE)

Bioavailability: Moderate. Best for: Concentrated EPA/DHA per capsule — allows higher potency but lower bioavailability; must be taken with a high-fat meal; form used in most clinical trials including REDUCE-IT.

Liquid Fish Oil

Bioavailability: High. Best for: High-dose supplementation without swallowing multiple capsules — flavored versions mask taste; allows precise dose titration.

Enteric-Coated Softgels

Bioavailability: High. Best for: Eliminating fishy burps — coating prevents capsule dissolution in the stomach, releasing omega-3s in the small intestine instead; slightly delayed absorption.

Full Fish Oil Guide

References

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