Cod Liver Oil vs Fish Oil: 7 Key Differences Before You Choose
Cod liver oil vs fish oil: not the same supplement
Many people treat the two as one product with two names, but the cod liver oil vs fish oil question has a real answer. Cod liver oil comes from the liver of cod, so it carries vitamins A and D. Fish oil comes from the flesh of oily fish and is mainly a source of omega-3 fats. Here are 7 differences that help you choose.
For a general introduction to omega-3 fats, see our omega-3 guide. This article focuses only on the comparison.
1. Different sources
The first point in cod liver oil vs fish oil is origin. The liver stores fat-soluble vitamins, which is why cod liver oil naturally contains vitamin A and vitamin D. Fish oil is pressed from whole oily fish such as anchovy, sardine and mackerel, then purified and, in better products, concentrated.
2. Vitamins A and D: the biggest difference
One softgel of NOW Cod Liver Oil 1000 mg provides 300 mcg RAE of vitamin A, about a third of the daily value, and 400 IU of vitamin D3, half the daily value. That is a useful small top-up for some adults, but it becomes a problem if you double the dose or stack it with other vitamin products.
3. Cod liver oil vs fish oil: EPA and DHA per capsule
The NOW cod liver oil softgel gives 70 mg EPA and 100 mg DHA, a total of 170 mg. A concentrated NOW Ultra Omega-3 softgel gives 500 mg EPA and 250 mg DHA, a total of 750 mg. To understand what each fat does, read EPA vs DHA.
| Product and daily dose | EPA | DHA | Total EPA + DHA per day | Extras |
|---|---|---|---|---|
| NOW Cod Liver Oil 1000 mg: 1 softgel with a meal | 70 mg | 100 mg | 170 mg | Vitamin A 300 mcg RAE and vitamin D3 400 IU |
| NOW Ultra Omega-3: 1 softgel with food | 500 mg | 250 mg | 750 mg | No added vitamins, enteric coated |
| NOW Ultra Omega-3: 2 softgels with food | 1,000 mg | 500 mg | 1,500 mg | Upper end of the label dose |
Matching 750 mg of omega-3 with cod liver oil would take more than 4 softgels, which would also multiply vitamins A and D well beyond the label. So never raise the cod liver oil dose to close the gap; in cod liver oil vs fish oil, the dose gap is real.
4. Cod liver oil vs fish oil: the vitamin A risk
Cod liver oil contains preformed vitamin A, which builds up in the liver. Long-term excess can cause headache, nausea, liver damage and weaker bones. The adult upper limit is 3,000 mcg a day from all sources combined, including multivitamins and liver in the diet.
- Do not combine it with another vitamin A supplement without asking a pharmacist.
- Avoid it if you take retinoid medicines such as isotretinoin for acne.
- People with liver disease should ask their doctor first.
5. Cod liver oil vs fish oil in pregnancy
Too much preformed vitamin A during pregnancy can harm the developing baby. A pregnant woman, or one planning a pregnancy, should not start cod liver oil on her own, and the NOW label says it is for adults. If extra DHA is needed in pregnancy, doctors usually prefer a purified fish oil or a dedicated prenatal product.
6. Cod liver oil vs fish oil: who suits each one?
- Cod liver oil: an adult who eats little fish and wants a modest omega-3 dose with vitamin D, and takes no other vitamin A supplement.
- Concentrated fish oil: someone who wants more EPA and DHA, or whose doctor advised omega-3 for high triglycerides. See omega-3 for heart health.
7. Shared safety points
Both are made from fish, so they are not suitable for people with a fish allergy. Both may increase bleeding tendency with anticoagulants such as warfarin or antiplatelets such as aspirin, so tell your doctor and surgeon. A fishy aftertaste or burping is common and is reduced by taking the softgel with a meal.
Cod liver oil vs fish oil vs eating fish
No supplement replaces a healthy diet. Heart organizations recommend eating oily fish such as sardines, mackerel or salmon twice a week, which provides omega-3 along with protein, selenium and vitamin D. If you eat fish regularly, you may not need either capsule. For healthy habits as you get older, read our healthy aging guide.
FAQ: cod liver oil vs fish oil
Can children take the NOW cod liver oil?
No, the label says adults only. Children need a product made for their age, chosen with a doctor.
Can I take it with a separate vitamin D supplement?
Each softgel already has 400 IU, so ask your doctor about your total intake if you take high-dose vitamin D.
Which is better for triglycerides?
In the cod liver oil vs fish oil choice, concentrated fish oil gives far more EPA and DHA per capsule, which is what matters for triglycerides.
Conclusion
The cod liver oil vs fish oil decision comes down to vitamins and dose. Cod liver oil offers a small omega-3 dose plus vitamins A and D; concentrated fish oil offers more EPA and DHA without added vitamins. Keep cod liver oil to one softgel a day, avoid extra vitamin A, and speak to your doctor in pregnancy. Both products are available at No Style Like pharmacy.
This article was reviewed by the No Style Like pharmacy content team. It is for general awareness only and does not replace advice from your doctor or pharmacist.
Excess vitamin A is harmful in pregnancy and to the liver, so do not exceed the label dose. For more information see the NIH vitamin A fact sheet.