Cod liver oil and omega-3 fish oil both provide EPA and DHA, but cod liver oil also contains vitamins A and D. Compare the differences, benefits and which option may suit you.
🕒 7 min read
Cod liver oil and omega-3 fish oil are not the same thing. Both can provide the long-chain omega-3 fatty acids EPA and DHA, but cod liver oil is extracted from cod livers and also contains vitamins A and D. Standard fish oil is generally produced from the tissues of oily fish and focuses primarily on EPA and DHA.
Neither is automatically better. The right choice depends on whether EPA and DHA are your main priority, whether you want additional vitamins A and D, and whether vitamin A is appropriate for you.
What's the difference between cod liver oil and omega 3?
The main difference is their nutrient profile. Cod liver oil provides omega-3 alongside vitamins A and D, while standard omega-3 fish oil primarily provides EPA and DHA.
| Feature | Cod liver oil | Omega-3 fish oil |
|---|---|---|
| Source | Oil extracted from cod livers | Usually oil from the tissues of oily fish |
| EPA | Yes | Yes |
| DHA | Yes | Yes |
| Vitamin A | Naturally present | Not normally a significant component |
| Vitamin D | Naturally present | Not normally a significant component |
| May suit you if... | You want omega-3 together with vitamins A and D and have no reason to avoid additional vitamin A | Your main priority is EPA and DHA or you want to avoid additional vitamin A |
| Pregnancy | Cod liver oil should be avoided because of its vitamin A content unless specifically advised by a healthcare professional | Check the individual product and seek advice if unsure |
The actual EPA and DHA content can also vary considerably between products, so compare the EPA and DHA figures on the label rather than simply looking at the total amount of fish oil or cod liver oil.
For a deeper explanation, read our guide to EPA and DHA and why you need both.
What are the benefits of omega-3 fish oil?
The main long-chain omega-3 fatty acids in fish oil are EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid).
EPA and DHA contribute to the normal function of the heart, with the beneficial effect obtained with a daily intake of 250mg EPA and DHA.1
DHA contributes to the maintenance of normal brain function and normal vision, with the beneficial effects obtained with a daily intake of 250mg DHA.1
Concentrated omega-3 fish oils can provide relatively high amounts of EPA and DHA without the additional vitamin A found in cod liver oil. This can make fish oil a straightforward option when EPA and DHA are the main priority.
You can browse Healthspan's full omega-3 range.
What are the benefits of cod liver oil?
Cod liver oil also provides EPA and DHA, so products supplying the required amounts can carry the same authorised heart, brain and vision claims as other sources of these omega-3 fatty acids.
The key additional difference is vitamins A and D. Where a cod liver oil product supplies sufficient amounts, vitamin A contributes to normal vision and normal immune-system function, while vitamin D contributes to the maintenance of normal bones and normal muscle function and to normal immune-system function.1
That does not make cod liver oil universally more beneficial than fish oil. Its vitamin A content is useful to consider because vitamin A is stored in the body and excessive intakes over a long period can be harmful.4
You can browse Healthspan's full cod liver oil range.
Which is better: cod liver oil or omega 3?
Neither is inherently better: they suit slightly different nutritional priorities.
A concentrated omega-3 fish oil may be more appropriate if EPA and DHA are your main priority, if you already get vitamins A and D elsewhere, or if you want to avoid additional vitamin A.
Cod liver oil may be an option if you want EPA and DHA alongside vitamins A and D and have no reason to avoid vitamin A.
If you are vegetarian or vegan, algae oil provides a fish-free source of EPA and DHA. Find out more in our guide to vegan omega-3.
Can you take cod liver oil and omega 3 together?
For most people there is little reason to take both purely to increase EPA and DHA, because both already provide these omega-3 fatty acids.
Taking both can also make it harder to keep track of your total EPA, DHA and vitamin intake. Cod liver oil adds vitamin A and D, so check the labels of all supplements you use and avoid unnecessary duplication.
If you want a higher EPA and DHA intake but already obtain vitamin D elsewhere, a concentrated fish oil may be simpler than combining several products.
If you take prescribed medicines, have a medical condition or are unsure which combination is appropriate, speak to your doctor or pharmacist.
How can you get omega 3 from your diet?
The NHS recommends eating at least two portions of fish a week, including one portion of oily fish. Oily fish such as salmon, sardines, trout, herring and mackerel are particularly rich in long-chain omega-3 fatty acids.2
Plant foods including flaxseed, chia seeds and walnuts contain alpha-linolenic acid (ALA), another omega-3 fatty acid. Algae-based supplements can provide EPA and DHA directly without fish.
What should you look for in an omega-3 or cod liver oil supplement?
The headline amount of oil on the front of a pack does not tell you how much EPA and DHA it contains. When comparing products, check:
- EPA and DHA per recommended daily serving rather than total fish-oil milligrams
- vitamin A and D content if choosing cod liver oil
- whether the format – capsule, liquid or other form – suits you
- whether marine ingredients are responsibly and sustainably sourced
- whether you are already getting the same nutrients from another supplement.
For more help comparing labels, read how much omega-3 you should take per day.
How much omega 3 should you take?
There is no single omega-3 supplement dose that is appropriate for every adult. The amount to consider is the EPA and DHA provided by the recommended serving, not simply the total milligrams of fish oil.
For the authorised heart-health claim, the beneficial effect is obtained with a daily intake of 250mg EPA and DHA combined. For the authorised brain and vision claims, the beneficial effect is obtained with 250mg DHA per day.1
Always follow the recommended intake on the product you are using. Higher intakes used for particular clinical purposes are different from general supplementation and should not be copied without appropriate professional advice.
Who should be cautious with cod liver oil?
Cod liver oil requires particular care because it contains vitamin A.
The NHS advises that pregnant women should not take cod liver oil or supplements containing vitamin A (retinol), as too much vitamin A can harm a developing baby.3
The NHS also advises people taking supplements containing vitamin A to ensure their average daily intake from food and supplements does not exceed 1.5mg (1,500 micrograms). If you eat liver every week, the NHS advises not taking supplements containing vitamin A.4
If you take prescribed medication, have a medical condition, are pregnant or are planning a pregnancy, check with a doctor or pharmacist before starting a new supplement.
