Cod Liver Oil
Commonly used for
ImmunityInflammationFocusHeart HealthHealthy Aging
Where to Buy
Our experts personally review each product we recommend for quality and cost effectiveness.
The cheapest product is usually low quality, but more expensive doesn’t always mean better.
The cheapest product is usually low quality, but more expensive doesn’t always mean better.
What is it? / Overview
Cod liver oil provides the same cardiovascular- and brain-supportive EPA/DHA as fish oil, plus naturally-occurring vitamin A (supports vision, epithelial tissue, and immune function) and vitamin D (supports calcium absorption, bone mineralization, and immune modulation) from the liver itself. This combined profile is why it's treated as its own distinct entry rather than a fish oil variant — the vitamin A and D content is clinically meaningful and changes the dosing and interaction picture (particularly around vitamin A upper-limit and additive vitamin D intake) in ways plain fish oil doesn't.
How is it used? / Administration
Form: Fish liver oil from cod (Gadus morhua and related species) — softgels, capsules, or liquid. Naturally contains EPA, DHA, vitamin A, and vitamin D, distinguishing it from plain fish body oil.
Typical dose studied: 1 tsp (5 mL) daily, or 1–2 softgels daily per product label. Typical daily targets: 250–500 mg combined EPA+DHA minimum, 400–1,000 IU vitamin D. Keep total vitamin A intake below the tolerable upper limit unless advised by a healthcare professional — potency varies significantly by manufacturer.
Timing: With meals, preferably one containing fat, for best absorption
Pregnancy: omega-3s are beneficial in pregnancy, but excess preformed vitamin A (retinol) can increase fetal risk — pregnant users should use only the product/dose their healthcare provider recommends and avoid exceeding the vitamin A upper limit. Third-party tested products preferred (contaminant and oxidation testing). Store in a cool, dry place away from light; refrigerate liquid formulations after opening if the label recommends it, and discard if it develops a rancid smell or taste.
How well does it work? / Evidence
✓ Well-established
Who should avoid it?
Avoid with: Food Allergies; Bleeding disorder / Coagulopathy; Hypercalcemia; End-stage liver disease / Cirrhosis
Interacts with: Anticoagulants and antiplatelet medications (warfarin, apixaban, rivaroxaban, clopidogrel, aspirin) — monitor at higher doses; Retinoid medications (isotretinoin, acitretin) — additive vitamin A exposure; Other vitamin D supplements — monitor total combined intake
Already taking it? Review total EPA/DHA, vitamin A, and vitamin D intake across all sources before increasing dose — cod liver oil provides meaningfully more vitamin A and D per serving than plain fish oil, so it isn't a drop-in swap without checking total intake. Excess cumulative vitamin A intake (hypervitaminosis A) is a real toxicity risk specifically because of that higher content -- this is a dosing/stacking risk rather than a diagnosable condition, which is why it's called out here rather than tracked as one.
Research & references
AHA Scientific Advisory on Omega-3 Fatty Acids. NIH Office of Dietary Supplements: Vitamin A Fact Sheet. NIH Office of Dietary Supplements: Vitamin D Fact Sheet.
Disclosure: Knozela is a participant in the Amazon Associates affiliate program. Some "Where to buy" links on this page are affiliate links -- if you make a purchase through them, Knozela may earn a commission at no additional cost to you.