Comparing Krill Oil vs. Fish Oil Benefits

Krill oil comes from a small, shrimp-like marine animal called krill. Fish oil comes from the tissues of oily fish, such as salmon, tuna, anchovies, and mackerel. Both oils contain EPA and DHA, two of the most well-researched omega-3 fatty acids.

This article discusses krill oil and fish oil, including why they're good for you, their differences, their safety, and where to find them.

Fish oil vitamin capsules

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Which Is Better, Krill Oil or Fish Oil?

While krill oil is often considered an alternative to fish oil, there are several key differences between the two. Some differences include:

  • Krill oil supplements have a reddish hue, while fish oil supplements are yellow or gold.
  • Krill oil comes from a small, shrimp-like crustacean, whereas fish oil comes from fatty fish.
  • The fatty acids in fish oil are found in triglycerides, while the fatty acids in krill oil are found in phospholipids, which may help increase the absorption of krill oil.
  • Fish oil is generally cheaper and easier to find in stores than krill oil.
  • Krill oil contains more antioxidants, including astaxanthin, that fish oil does not.
  • Fish oil has more research to support its health benefits than krill oil.
  • Fish oil typically contains more omega-3 fatty acids per serving than krill oil.
  • Some manufacturers and consumers claim krill oil is more palatable than fish oil and does not produce a fishy aftertaste.
  • Primarily due to the lack of research on krill oil, the health benefits evidence is inconclusive.

Algae and Cod Liver Oil

Algae oil has a similar nutritional composition to fish oil. It is considered a proven, sustainable plant-based omega-3 alternative to fish oil. Cod liver oils contain omega-3s and have vitamins A and D.


Krill and fish oils are excellent sources of omega-3 fatty acids, which may lower levels of inflammation in the body and support fetal development and healthy aging.

Studies show that eating omega-3-rich fatty fish and seafood is associated with a lower risk of several chronic diseases, including heart disease. However, it is unclear whether these benefits come from simply eating these foods or their omega-3 content.

A decent amount of evidence suggests omega-3 supplementation may be effective at reducing levels of triglycerides (a type of fat in the blood) and alleviating symptoms of rheumatoid arthritis. One study found that krill oil significantly lowers triglyceride levels in patients with high triglycerides (hypertriglyceridemia).

In another study, researchers found krill oil was slightly more effective than fish oil at lowering triglyceride levels. The reduction in triglycerides depends on the dose of omega-3s rather than the type of oil consumed.

In food or supplement form, EPA and DHA omega-3s may reduce the risk of coronary heart disease by lowering high blood pressure, specifically among people who already have hypertension.

Omega-3 Content

The omega-3 content of krill and fish oil varies considerably between supplements. However, krill oil generally contains fewer omega-3s per serving (and soft gel) than fish oil.

The dose of EPA and DHA in krill oil supplements generally ranges from 45 to 200 milligrams (mg) per soft gel. In contrast, the amount of EPA and DHA in fish oil products ranges from 300 to 2,200 mg per soft gel or teaspoon.

Are They Safe to Take Every Day?

Omega-3 supplements, including fish and krill oils, are generally considered safe when recommended. Side effects that are reported are usually mild, consisting of:

If you are allergic to fish or shellfish, you should avoid taking fish oil or krill oil supplements until you speak with your healthcare provider.

Fish oil or krill oil may have blood-thinning effects at high doses and can interact with certain medications, such as Coumadin or Jantoven (warfarin).


Experts recommend consuming 6–8 ounces (about two servings) of fish per week. Four ounces of Atlantic salmon provide around 3 grams of omega-3 fatty acids.

However, consuming high doses of more than 900 mg of EPA plus 600 mg of DHA daily for several weeks may reduce immune function by suppressing the body's inflammatory responses.

Krill Oil

Krill oil is a safe alternative to fish oil, with no significant reported side effects. Krill also do not contain unsafe accumulations of mercury because they are low on the ocean's food chain.

Manufacturers of krill oil often claim that it does not cause a fishy aftertaste, fish burps, or reflux, all of which are common side effects of fish oil supplements. However, some individuals may still experience these side effects.

Fish Oil

It's recommended to consume 6–8 ounces of seafood per week, preferably oily fish. This increases to eight to 12 ounces of fish and seafood per week during pregnancy and breastfeeding to support the health of your developing baby.

It is important to choose fish low in mercury and high in EPA and DHA during pregnancy. Fish high in mercury include:

  • King mackerel
  • Marlin
  • Shark
  • Swordfish

Fish low in mercury include:

  • Canned light tuna
  • Salmon
  • Sardines
  • Herring

Fish oil supplements are purified of environmental toxins like mercury, but they still may cause some minor side effects like stomach discomfort and belching.

Krill and Fish Oil Supplements During Pregnancy

If you find it challenging to get enough omega-3 fatty acids from food, your healthcare provider may recommend a quality fish oil supplement during pregnancy. More research on the safety of krill oil in pregnant individuals is needed. It's best to be safe and avoid it unless otherwise recommended by your healthcare provider.

Vegetarian and Vegan Omega-3 Sources

Omega-3s are widely available in a variety of different plant foods. Plant-based omega-3s from algal oil typically provide about 100–300 mg of DHA, with some containing EPA. The omega-3s are generally present in the triglyceride form. The bioavailability of DHA from algae oil is similar to that from cooked salmon.

Vegan foods with omega-3s include:

  • Chia seeds
  • Flaxseed
  • Seaweed
  • Algae
  • Hemp seeds
  • Walnuts

Where to Find Krill and Fish Oils

You can purchase fish oil and krill oil from most drugstores. Krill oil may be a little more challenging to find in stores, but it can easily be bought online. Always check to ensure a third party tests a supplement for any contamination from harmful materials.


Krill oil is derived from small, shrimp-like crustaceans, while fish oil comes from oily fish. Despite their differences, both oils are good sources of omega-3 fatty acids, which play an essential role in many bodily functions. While it appears that krill oil is better absorbed by the body and contains more antioxidants, further studies are needed to determine if it offers more health benefits than fish oil.

Frequently Asked Questions

  • Should some people not take krill oil or fish oil?

    Although considered safe, people who take blood thinners should avoid krill oil and fish oil unless otherwise recommended by a healthcare provider. They may cause your blood to become thinner than it should. People with a fish or shellfish allergy should also avoid fish or krill oil.

  • Does krill oil help your liver?

    While research on krill oil is needed, some evidence shows omega-3 supplementation may help improve fat accumulation and markers of fatty liver disease in individuals with diabetes and nonalcoholic fatty liver disease (NAFLD).

  • What are the benefits of krill oil for bodybuilders?

    Some new evidence suggests krill oil supplementation may help improve muscle function and size in healthy, older adults. However, more research is needed to fully understand the benefits of krill oil for athletes and bodybuilders.

15 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Lindsey DeSoto, RD, LD
Lindsey Desoto is a registered dietitian with experience working with clients to improve their diet for health-related reasons. She enjoys staying up to date on the latest research and translating nutrition science into practical eating advice to help others live healthier lives.