Krill Oil vs. Fish Oil: Similarities & Differences Explained

Dec 13, 2023 Krill OilOmega-3 5 MIN

Krill Oil vs. Fish Oil: Similarities & Differences Explained

Krill Oil and Fish Oil, what's the difference? And why should I be interested in taking them? Krill Oil and Fish Oil are both sources of heart-healthy Omega-3 Fatty Acids EPA and DHA, essential components of the body's cell membranes. Krill Oil is sourced from krill, and Fish Oil is sourced from oily  fish, as the names imply, but to truly understand the difference, we'll need to dive in a bit deeper!†

What is Krill Oil?

Origin & Source

You've probably heard of "krill" before, but what exactly are krill? They're a lot like shrimp, just much smaller than what you'll find on your plate! Krill are tiny shellfish that travel in huge swarms, sometimes big enough to be seen from space![1] Though they may be tiny, krill are part of many Southeast Asian diets, where they are made into a fermented paste. Nature Made sources the krill for our Krill Oil products from the Antarctic Ocean.

Main Components

Krill Oil is one source of heart-healthy Omega-3 Fatty Acids EPA and DHA, phospholipids, and Astaxanthin. EPA and DHA, also known by their full names Eicosapentaenoic acid and Docosahexaenoic acid, are long-chain fatty acids. Astaxanthin, a carotenoid with antioxidant properties, is the source of Krill Oil's vibrant red color!†

What is Fish Oil?

Origin & Source

Fish oil, where does it come from? The answer may not surprise you; it's in the name. Fish! Omega-3 Fatty Acids EPA and DHA build up in the tissues of oily or fatty fish like salmon, tuna, sardines, and anchovies. These fish don't produce EPA and DHA themselves, but they accumulate it by eating either Omega-3-producing microalgae or smaller fish that eat algae.

Main Components

Fish Oil contains primarily EPA and DHA, which are Omega-3 Fatty Acids. EPA stands for eicosapentaenoic acid, and DHA for docosahexaenoic acid, both long-chain Omega-3s containing 20 and 22 carbon atoms, respectively.[3] These Omega-3s are absorbed at a rate of 95%, and they play a structural role in constructing cell membranes.[3] Fish Oil also contains other Fatty Acids in smaller amounts, which have similar structures.†

Heart-healthy Omega-3 Fatty Acids are a shortfall nutrient; over 2/3 of U.S. adults don't consume enough EPA and DHA in their daily diet to meet recommendations based on the U.S. Dietary Guidelines for Americans.[4]†

Krill Oil vs. Fish Oil: Similarities & Differences

Shared Nutritional Benefits

  1. Omega-3 Fatty Acids - Krill Oil and Fish Oil contain Omega-3 Fatty Acids EPA and DHA. Why is that? Well, understanding who makes these acids can help make sense of it. Neither krill nor fish create these fatty acids; a variety of tiny microalgae produce them, microscopic plants that form the bottom layer of much of the ocean's food chain. Krill eat these microalgae, and as a result, the fatty acids present in microalgae build up in krill. In turn, krill and other small fish are eaten by larger, oily or fatty fish like tuna and salmon, so the acids are then absorbed into their fatty tissues. Neither krill nor fish produce these independently, but they consume and concentrate Omega-3s up through the food chain.
  1. Heart Health - EPA and DHA help support a healthy heart. Supportive but not conclusive research shows that consumption of EPA and DHA Omega-3 Fatty Acids from Fish Oil may reduce the risk of coronary heart disease. EPA and DHA are essential to building and supporting cell membrane health and function.[5]†

Distinctive Features of Krill Oil

Krill Oil has a distinctive structure when compared to fish oil: much of the EPA and DHA in krill oil is bound to phospholipids. Phospholipids are a type of lipid, or fat, that contains a phosphate group bonded with two fatty acids. This phospholipid structure might influence the absorption of EPA and DHA; the effects of higher phospholipid content in krill oil in relation to absorption have been clinically studied.[6] In addition, studies have found krill oil to have a higher 72-hour bioavailability than fish oil.[7]†

Distinctive Features of Fish Oil

Fish Oil is one of the best dietary sources of EPA and DHA.[8] The American Heart Association recommends at least two servings of oily or fatty fish per week, but if that doesn't fit your diet, Fish Oil supplementation can provide an alternative source of EPA and DHA.[9] These Omega-3 Fatty Acids are incorporated into the cell membranes of all types of tissues in the body within days of consumption.[10]†

Some Fish Oil supplements may have higher concentrations of EPA and DHA than others. If your diet includes dietary Fish Oil from regular consumption of oily or fatty fish like salmon, consider a lower dosage. Nature Made® Fish Oil 1000 mg Softgels provide 500 mg of EPA and DHA, while Ultra Omega-3†† from Fish Oil 1400 mg Softgels provide a total of 1000 mg of Omega-3 Fatty Acids, including 683 mg of EPA, 252 mg of DHA, and 65 mg of other Omega-3s as Ethyl Esters.†

Tips for Choosing an Omega-3 Supplement

Finding the right Omega-3 Supplement is easy, as Nature Made® has many options to suit your needs. If you are interested in the benefits of phospholipid absorption, Nature Made® Superior Absorption** Krill Oil 500 Mg Softgels offer an exciting new way to provide yourself with heart-healthy Omega-3s. Fish Oil Omega-3s come in various doses and forms, from Burp-Less♦ Fish Oil 1000 mg Softgels to Fish Oil Gummies with 57 mg of Omega-3 Fatty Acids per serving. Extra Strength Omega-3†† From Fish Oil Softgels give you a high dose of Omega-3s to help support a healthy heart, brain, eyes, and mood. Picking the right Omega-3 Supplement has never been easier!†

**Superior omega-3 fatty acid (EPA + DHA) absorption compared to an equal amount of EPA + DHA from regular triglyceride fish oil.

♦ Specially made to reduce fish odor and aftertaste, and fishy burps.

††As ethyl esters

† These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent any disease.


  1. Belcher A, Fielding S, Gray A, et al. Experimental determination of reflectance spectra of Antarctic krill (Euphausia superba) in the Scotia Sea. Antarctic Science. 2021;33(4):402-414. doi:10.1017/S0954102021000262
  2. Britannica, T. Editors of Encyclopaedia (2018, Jan 3). fish oil. Encyclopedia Britannica.
  3. Office of dietary supplements - Omega-3 Fatty Acids: Professional. NIH Office of Dietary Supplements. Feb 15, 2023. Accessed Oct 27, 2023.
  4. USDA. Dietary Guidelines for Americans: 2020-2025. December 2020. Accessed on: Oct 27, 2023.
  5. Harvard T.H. Chan. Omega-3 Fatty Acids: An Essential Contribution. The Nutrition Source. Published May 22, 2019.
  6. Ramprasath VR, Eyal I, Zchut S, Shafat I, Jones PJ. Supplementation of krill oil with high phospholipid content increases sum of EPA and DHA in erythrocytes compared with low phospholipid krill oil. Lipids Health Dis. 2015;14:142. Published 2015 Nov 4. doi:10.1186/s12944-015-0142-y
  7. Köhler A, Sarkkinen E, Tapola N, Niskanen T, Bruheim I. Bioavailability of fatty acids from krill oil, krill meal and fish oil in healthy subjects--a randomized, single-dose, cross-over trial. Lipids Health Dis. 2015;14:19. Published 2015 Mar 15. doi:10.1186/s12944-015-0015-4
  8. Nichols PD, Petrie J, Singh S. Long-chain omega-3 oils-an update on sustainable sources. Nutrients. 2010;2(6):572-585. doi:10.3390/nu2060572
  9. Office of dietary supplements - Omega-3 Fatty Acids. NIH Office of Dietary Supplements. Jul 18, 2022. Accessed Oct 27, 2023.
  10. Surette ME. The science behind dietary omega-3 fatty acids. CMAJ. 2008;178(2):177-180. doi:10.1503/cmaj.071356


Graham Morris

NatureMade Copywriter

Graham has a degree in film with a focus on screenwriting from the University of California, Santa Cruz. He enjoys learning new things and finding the best, most engaging way to communicate them to a wide audience. Graham appreciates simplicity in life and nutrition, and wants to find the easiest, no-stress ways to stay healthy.

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Lynn M. Laboranti, RD

Science and Health Educator

Lynn is a Registered Dietitian (R.D.) and is a member of the Medical and Scientific Communications team at Pharmavite. She has over 20 years of experience in integrative and functional nutrition and has given lectures to health professionals and consumers on nutrition, dietary supplements and related health issues. Lynn frequently conducts employee trainings on various nutrition topics in addition to educating retail partners on vitamins, minerals and supplements. Lynn has previous clinical dietitian expertise in both acute and long-term care, as well as nutrition counseling for weight management, diabetes, and sports nutrition. Lynn earned a bachelor’s of science in Nutrition with a minor in Kinesiology/Exercise Science from The Pennsylvania State University. She earned a M.S. degree in Human Nutrition from Marywood University in Scranton, Pennsylvania. Lynn is an active member of the Academy of Nutrition and Dietetics, Sports Cardiovascular and Wellness Nutritionists, Dietitians in Functional Medicine, and holds a certification in Integrative and Functional Nutrition through the Academy of Nutrition and Dietetics.

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