Krill Oil vs Cod Liver Oil – Which Is Better? Let’s Compare

Krill oil and cod liver oil are two popular fish oils people like to use. For this reason many people wonder which one is better. Let’s answer, is cod liver oil better than krill oil?

Krill oil is better than cod liver oil for omega-3 fatty acid intake. Krill oil provides 3.50 grams of omega-3 per tablespoon, cod liver oil provides 0.84 grams. If vitamins A and D are more desired then cod liver oil is better due to its higher percentage of vitamins.

This article will take a closer look at the two oils and compare their nutrients, costs, benefits, mercury levels and side effects.

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Disclaimer: Above link and others in this article are affiliate links which means I may earn a small commission at no extra cost to you. As an Amazon associate I earn from qualifying purchases. Always check with your physician prior to taking supplements or changing your nutrition habits.

The Difference Between Krill Oil and Cod Liver Oil

Many people wonder if there is a difference between the fish oils available on the market. When discussing krill and cod liver oils, let’s answer, what is the difference between krill oil and cod liver oil?

Krill oil is extracted from Antarctic krill and cod liver oil is extracted from the livers of cod fish. Krill oil contains the omega-3 fatty acids DHA and EPA, and phospholipid-derived fatty acids. Cod liver oil contains omega-3 fatty acids and vitamins A and D.

What is Krill Oil?

Krill oil is extracted from Antarctic Krill and is commonly used as a dietary supplement. Krill oil provides the omega-3 fatty acids eicosapentaenoic acids (EPA), docosahexaenoic acids (DHA) and phospholipid-derived fatty acids.

Many people are familiar with the fish other fish oils come from. Krill are less known to most people 1. Therefore let’s take a look at what krill is. Krill is a shrimp-like crustacean found in the oceans all over the world.

Other common crustaceans include shrimp, lobster, crabs, barnacles and more. What makes krill oil unique from other fish oils is their phospholipid-derived fatty acids. Combined with omega-3 fatty acids, studies have shown omega-3s are absorbed more 2.

krill oil
Krill oil soft gels

What is Cod Liver Oil?

Cod liver oil is oil extracted from the livers of codfish. The cod liver oil is used as a dietary supplement and provides the omega-3 fatty acids eicosapentaenoic acids (EPA), docosahexaenoic acids (DHA), vitamins A and D.

A tablespoon of cod liver oil contains 4,080 mcg of vitamin A, 34 mcg (1,360 IU) of vitamin D and 0.84 grams of omega-3 fatty acids 3. What makes cod liver unique from other fish oils is their vitamins A and D.

Krill Oil vs Cod Liver Oil: Nutrient Comparison

The following table compares all the nutrients contained in cod liver oil and krill oil:

Nutrient Cod Liver Oil (1 Tbsp) Krill Oil (1 Tbsp)
Calories 41 122
Omega-3 0.84 g 3.50 g
Total Fat 4.5 g 13.6 g
Saturated Fat 1.0 g 3.0 g
Cholesterol 25 mg 21 mg

Nutrient sources 4 5

When comparing the nutrients above there is a large difference between the two fish oils. Krill oil contains approximately 420% more omega-3 fatty acids than cod liver oil. In addition, krill oil contains phospholipid-derived fatty acids.

Studies have shown by combining omega-3 with phospholipid-derived fatty acids may increase the absorption of the omega-3s. Krill oil also contains astaxanthin, a keto-carotenoid which gives krill oil its color 6.

Cod liver oil contains less calories, total fat, saturated fat and cholesterol than krill oil. This is due to its less amount of healthy fats. Cod liver oil also contains more vitamins A and D than krill oil. If you’re receiving omega-3s from another source, the cod liver oil may be a better choice.

Fish oil and fresh fish are known for being a part of many diets like keto or heart healthy.

If you’re eating low-carb or want to give keto a try, many of my clients have followed this 28-Day Keto Challenge with great success. Visit their website and check it out.

Krill Oil and Cod Liver Oil Costs

Deciding on which oil to consume may involve more than determining whether vitamins or omega-3s are more important. With the rising costs of almost everything in the supermarkets, the cost is a likely factor.

Therefore, which costs more, krill oil or cod liver oil?

Krill oil costs more than cod liver oil. The average cod liver oil price is $18.97 per 180 softgels and krill oil is $107.97 per 180 softgels.

I checked the following two stores for the prices of each oil and found the following results.


  • Krill oil – NOW Brand (1,000 mg, 60 Softgels)
    • $35.99
  • Cod Liver Oil – NOW Brand (1,000 mg, 180 Softgels)
    • $18.37


  • Krill Oil – Kirkland Brand (500 mg, 160 Softgels)
    • $24.99
  • Cod Liver Oil – NOW Brand (1,000 mg, 180 Softgels)
    • $22.99

Krill oil and cod liver oils are easy to locate. I typically can find more affordable prices and availability on Amazon, Check them on Amazon and the current prices here, Fish Oils.

cod liver oil softgels
Cod liver oil softgels

Krill Oil and Cod Liver Oil Mercury Levels

The FDA and EPA have issued warnings and suggestions regarding mercury levels in fish and how often they should be consumed 7. This is especially important for the following:

  • Developing children
  • Young infants
  • Pregnant women

They established a list of the following:

  • Fish to avoid
  • Good choices
  • Best fish

Therefore, does krill oil, or cod liver oil have more mercury?

Cod liver oil and krill oil have similar levels of mercury. Cod fish and small crustaceans like krill are listed on the FDA’s best choices of fish regarding mercury levels. 

If you’re pregnant, breast feeding or has a young child, Always check with a physician prior to eating new foods or changing your dietary habits.

Mercury warnings can change over time or affect only a particular area or state. Please check with your local EPA and FDA for the current recommendations 8.

I recently completed an article comparing cod liver oil and fish oil. Find out which costs more or had more mercury among other things, Cod Liver Oil vs Fish Oil: What’s The Difference? We Compare.

How To Determine The Correct Amount of Krill Oil and Cod Liver Oil

There’s no official recommendation for how much DHA and EPA omega-3 to take every day. Therefore, to determine how much DHA and EPA Omega-3 fatty acids to take:

  • Confer with a physician first.
  • Compare the dosage on a supplement bottle to the amount provided in a serving of whole fish.
  • Read the recommendations on the krill oil and cod liver oil supplement bottle.

Additional tips about taking krill oil or cod liver oil:

  • Determine if the omega-3 fatty acids or Vitamins A and D are more important for you.
  • If omega-3 is more important the krill oil provides more.
  • If Vitamins A and D are more important, the cod liver oil may be a better choice.
  • Don’t take krill oil and cod liver oil supplements together.
  • Take cod liver or krill oil with food to aid digestion and absorption of the oil.
  • Never discontinue medication for a fish oil supplement without conferring with a physician first.

The Health Benefits of Krill oil and Cod Liver Oil

The omega-3 fatty acids provided by krill oil and cod liver oil help provide the many benefits listed below. Fatty acids are not made by the body which is why many medical professionals and nutritionists recommend adding omega-3 sources to the diet.

Sources of omega-3 fatty acids include:

  • Fish (seafood)
  • Fish oil supplements like krill oil and cod liver oil
  • Seeds

The three common omega-3 fatty acids often referred to include:

  • Docosahexaenoic acids (DHA)
  • Eicosapentaenoic acids (EPA)
  • Alpha-linolenic acids (ALA)

DHA and EPA are mainly found in seafood and ALA is found in plant based foods like seeds. ALA converts to DHA and EPA but the conversion rate is very low. Therefore, it’s best to consume DHA and EPA to receive the optimal benefits 9.

Find out how cod liver oil compared to omega-3 in my recent article, Cod Liver Oil vs Omega 3: Which Is Better? Let’s Compare.

The health benefits of krill oil and cod liver oil include the following:

Heart Health

Krill oil and cod liver oil may help keep the heart healthy by preventing the following:

  • High blood pressure
  • High cholesterol
  • Heart attacks
  • Stroke
  • Heart disease

The fish oil helps to accomplish this by the following:

  • Lowering bad cholesterol and increasing good cholesterol.
  • Lowering blood pressure.
  • Lowering the fat cells in the blood (triglycerides).
  • Improving blood vessel function.

A study released in 2015 involved 47 people who supplemented with krill oil for four weeks. The results found krill oil improved the health of blood vessels and insulin resistance more than olive oil. After 17 weeks, krill oil also improved good cholesterol 10.

Addition research examined over 34 previous studies which included 1,356 people. It was found the omega-3s in fish oil lowered both systolic and diastolic blood pressure. The researchers found a larger reduction in people with high blood pressure 11.


Cod liver and fish oils have been shown to have anti-inflammatory abilities. For this reason, taking fish oil supplements has been known to help prevent inflammation-related diseases like arthritis, diabetes and some cancers 12.

Blood Circulation

Omega-3 fatty acids are later converted into other helpful molecules. For this reason, researchers believe the fatty acids help keep a body’s blood vessels strong, capable and flexible. This allows for better blood flow and improved circulation of oxygen 13.

Cognitive Issues

The Omega-3 levels found in cod liver oil and krill oil can help build up and maintain brain cells. Brain cells are constantly developed and repaired by fatty acids. This can decrease the chance of cognitive degenerative diseases like Parkinson’s or Alzheimer’s 14.

Eye Health and Improved Vision

Due to their omega-3s, fish oil can help prevent retina deterioration. If the intraocular pressure (the fluid pressure in the eye or IOP) is greater than the normal range of 12-22 mm/Hg, glaucoma could occur or will at least be a considerable risk.

With a diet rich in omega-3 fatty acids, eye problems can be less likely. They help keep that IOP at a healthy level. This is another fantastic reason to take fish oil supplements 15.

Krill Oil and Cod Liver Oil Side Effects

Krill oil and cod liver oil are considered safe, but there are some minor side effects. Therefore, a physician should be consulted prior to taking any fish oil supplement. Krill oil and cod Liver oil possible side effects include the following:

Bad Breath/Body Odor

The oils in the fish oil supplements can linger a while. This can result in bad breath lasting longer than is comfortable. This is more so when taking the liquid form of krill or cod liver oil.

The fish oil supplements are made from pungent oils. Therefore, the fishy “grease” can stay in your system for quite some time and possibly increase the amount you sweat (but this does not happen often).


Stomach cramps and digestive issues have been reported in rare cases. In addition, some people have experienced heartburn and loose stool in response to the upset stomach.

Always proceed with caution when taking fish oil and don’t take too much at a time. Following your physician’s recommendation, reading labels and suggested measurements carefully are beneficial with or without side effects.


Allergies exist for many things including shellfish. Although having a shellfish allergy doesn’t automatically disqualify someone from taking fish oils, there may have been cross-contamination in the making and manufacturing process.

Labels and medical professionals could elaborate further on any additional inquiries.


In rare cases, fish oil supplements have been known to cause nose bleeds and “easy bleeding.” This means if you get a cut, the bleeding might have a hard time stopping. Although this is rare, it can be dangerous.

If this or any other concerns come up, it might be best to stop taking the supplements and speak to a physician.

Unhealthy levels of Vitamin A and D

More so with cod liver oil, unhealthy levels of both vitamins may exist. This is especially so if taking more than the recommended dosage of fish oil. Although this is often debated, it’s good to be aware of this and discuss it with a doctor.

In addition, fish oil may cause:

  • Nausea
  • Rash
  • Reduced vitamin E levels
  • Negative reactions with certain medications

Addition article resources 1617 18 19 20 21 22 23

Read Next Additional Fish Oil vs Fish Oil Articles!

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Article Resources: Foods For Anti-Aging follows strict guidelines to ensure our content is the highest journalistic standard. It's our mission to provide the reader with accurate, honest and unbiased guidance. Our content relies on medical associations, research institutions, government agencies and study resources. Learn more by reading our editorial policy.
  1. Wikipedia: Krill[]
  2. Wikipedia: Krill oil[]
  3. Wikipedia: Cod-liver oil[]
  4. Nutrition Value: Fish oil, cod liver[]
  5. National Center for Biotechnology Information: Krill for human consumption: nutritional value and potential health benefits[]
  6. Wikipedia: Astaxanthin[]
  7. FDA: Advice about Eating Fish[]
  8. National Center for Biotechnology Information: Mercury accumulation in largemouth bass (Micropterus salmoides) in a Florida lake[]
  9. National Institutes of Health: Omega-3 Fatty Acids[]
  10. National Center for Biotechnology Information: Effects of krill oil on endothelial function and other cardiovascular risk factors in participants with type 2 diabetes, a randomized controlled trial[]
  11. Circulation: Does fish oil lower blood pressure? A meta-analysis of controlled trials[]
  12. National Center for Biotechnology Information: Cod liver oil (n-3 fatty acids) as an non-steroidal anti-inflammatory drug sparing agent in rheumatoid arthritis[]
  13. National Center for Biotechnology: Marine Omega-3 Supplementation and Cardiovascular Disease[]
  14. National Institute of Health: Omega-3 Fatty Acids[]
  15. National Center for Biotechnology Information: Cod liver oil: a potential protective supplement for human glaucoma[]
  16. National Center for Biotechnology Information: Cod Liver Oil Supplement Consumption and Health: Cross-sectional Results from the EPIC-Norfolk Cohort Study[]
  17. National Center for Biotechnology Information: Mother Was Right About Cod Liver Oil[]
  18. National Center for Biotechnology Information: Role of Cod Liver Oil in Preventing Myocardial Infarction[]
  19. National Center for Biotechnology Information: Fish, Fish Oils and Cardioprotection: Promise or Fish Tale?[]
  20. National Center for Biotechnology Information: Effects of krill oil and lean and fatty fish on cardiovascular risk markers: a randomized controlled trial[]
  21. National Center for Biotechnology Information: A brief review of krill oil history, research, and the commercial market[]
  22. National Center for Biotechnology Information: Effects of Antarctic krill oil on lipid and glucose metabolism in C57BL/6J mice fed with high fat diet[]
  23. National Center for Biotechnology Information: Krill oil reduces plasma triacylglycerol level and improves related lipoprotein particle concentration, fatty acid composition and redox status in healthy young adults – a pilot study[]

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