Note: The U.S. Food and Drug Administration (FDA) does not approve supplements for safety or effectiveness. Talk to a healthcare professional about whether a supplement is the right fit for your individual health, and about any potential drug interactions or safety concerns.
Plenty of research shows that eating omega-3 fatty acids may help lower the risk of chronic diseases like heart disease.While eating fatty fish is one of the best ways to get omega-3s, nearly 90 percent of adults don’t eat enough seafood to reap these benefits.
Fish oil supplements, including krill oil — which comes from a tiny, prawn-like crustacean — can help boost your omega-3 levels. Learn about the possible benefits and side effects of krill oil, as well as the various forms it comes in, and how to choose one. Always speak to your doctor or healthcare provider before you try a new supplement.
Why Might Krill Oil Be Good for You?
Krill oil is a good source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), two key types of omega-3 fatty acids. “Omega-3 fats are beneficial for heart, brain, and cell health,” says Vicki Shanta Retelny, RDN, who is based in Chicago.
“Krill oil can be used as an alternative to fish oil and has some compelling benefits,” adds Sarah Kamely, RDN, who helps clients with an integrative approach in Miami.
1. It May Support Heart Health
Chronic (ongoing) inflammation is linked to several diseases, including heart disease, so the anti-inflammatory effects of krill oil may help your heart stay healthy. Polyunsaturated fatty acids like omega-3s help your body make fewer inflammatory proteins in your blood vessels and in your heart itself.
Research suggests that krill oil may benefit the heart by helping to lower triglycerides, a type of fat in the blood that can increase your risk of heart disease and stroke if levels get too high. One study of people with severe hypertriglyceridemia (a condition of high triglyceride levels), in particular, found that those who took krill oil supplements for 12 weeks saw a 26 percent decrease in triglycerides.
Also, a meta-analysis of 14 randomized controlled trials found that daily krill oil supplementation was linked with good effects on total cholesterol and low-density lipoprotein cholesterol (LDL), often called “bad” cholesterol.
“If deemed appropriate on an individual-client basis, I would feel comfortable recommending krill oil as a supplement for its heart-health benefits,” says Kamely.
2. It Provides Antioxidants
Krill oil contains astaxanthin, a pigment that gives krill its pink-red color. Astaxanthin also belongs to a group of antioxidants called carotenoids, which help battle free radicals in your body that can contribute to disease.
While free radicals are created by normal metabolic processes in your body, some foods can trigger a larger amount to be produced than others. Too-high levels of free radicals can cause oxidative stress, leading to cell damage and risk for health issues like cancer and heart disease.
Astaxanthin, in particular, may offer unique benefits. “This carotenoid has been shown to help fight off the negative effects of free radicals on both our brain and nervous system,” says Amy Kimberlain, RDN, CDCES, a Miami-based spokesperson for the Academy of Nutrition and Dietetics.
As an antioxidant, astaxanthin is 6,000 times more potent than vitamin C. And it may protect your brain and nervous system against free-radical damage that contributes to age-related issues like dementia, a decline in mental ability that affects daily tasks.
3. It Might Promote Gut Health
Krill oil may support gut health by reducing intestinal inflammation and increasing gut microbial diversity, which can help control how well your intestines work. When uncontrolled, intestinal inflammation is linked with inflammatory bowel disease (IBD). That’s a group of chronic conditions that cause diarrhea, abdominal pain and cramping, loss of appetite, and other symptoms. More research is needed, though, to find treatment options for IBD.
Krill oil may also support the health of the intestinal barrier, a layer of cells that protects the interior of the intestine from the outside environment, says Kamely. It also may improve the diversity of the gut microbiome, the tiny organisms that live in your gut, she says.
Early research suggests that krill oil may dampen inflammatory proteins and promote bacteria-killing immune system cells. This may lead to greater microbial diversity in your intestines, a sign of gut health — but more research is needed.
Still, krill oil may be a worthwhile addition to your routine if you have gut inflammation or IBD, Kamely says. It also might be worthwhile, she says, if you have increased intestinal permeability: leaky gut, or the theory that the intestines can allow toxins from the digestive tract into the bloodstream. Just be sure to talk with your doctor before you use krill oil to help manage gut issues.
4. It May Ease Arthritis and Joint Pain
Thanks to their ability to lower inflammation, the omega-3s in krill oil may reduce joint pain in people with inflammatory joint conditions like arthritis, says Kimberlain.
In one study of adults with mild-to-moderate knee osteoarthritis (a wear-and-tear condition that affects the knee joint), those who took 4 grams (g) of krill oil daily for six months saw greater improvements in knee pain, stiffness, and physical function than those who took a placebo.
5. It May Provide PMS Pain Relief
In general, the omega-3s in krill oil have anti-inflammatory properties that may help ease pain, including menstrual pain.
An older study found that women who take krill oil used fewer pain relievers for premenstrual syndrome (PMS)-related pain compared with those who take fish oil. But this research is more than 20 years old and included only 70 participants. Newer studies with more people are needed to understand if and how krill oil may help manage PMS.
Still, Kamely says that taking pain-relieving medications — specifically nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen (Advil) or naproxen (Aleve) — too often can harm your gut lining. So, krill oil may be a safer alternative, especially if PMS symptoms are particularly painful, she says.
Can Krill Oil Help You Lose Weight?
There’s not much research that explores whether krill oil leads to weight loss or changes in body composition — and the studies that do exist aren’t promising.
In a small study involving 26 women with body mass indexes (BMIs) that qualified as overweight, taking 3 g of a krill oil supplement per day for eight weeks did not result in reductions in waist circumference.
Krill oil may have indirect benefits on weight loss by lowering inflammation, says Kathryn Durston, RDN, owner of Naturally Good Nutrition in Grand Rapids, Michigan. There’s substantial evidence to show that there is a direct connection between obesity and inflammation. But experts can only confidently say that obesity leads to inflammation thus far, not that inflammation leads to obesity. “That being said, prioritizing a balanced diet, exercise routine, and stress management are more worthwhile habits for losing weight,” Durston says.
Potential Risks and Side Effects of Krill Oil
Talk to your doctor before taking krill oil if you have a known fish allergy. Also check with your doctor first if you take blood thinners, have a bleeding disorder, or are going to have surgery, since the supplement can cause blood thinning.
Some doctors might suggest that pregnant women take fish oil, as omega-3s may support fetal development, prevent preterm labor, lower the risk of high blood pressure during pregnancy (preeclampsia), and boost mood. While the European Food Safety Authority approved the use of krill oil during pregnancy in 2014, the U.S. Food and Drug Administration (FDA) does not have specific guidance about the supplement. So, talk to your doctor before adding it to your routine.
Getting too many omega-3 fatty acids may even weaken your immune system. Be sure to take the dose recommended by your healthcare provider.
The potential side effects of krill oil supplements include the following, according to Kimberlain:
Finally, the FDA doesn’t regulate supplements the way it does conventional medicines. So, there are risks to be aware of, such as contamination with mercury or other quality issues.
Forms of Krill Oil
Krill oil supplements are available in the following forms:
Capsules
Liquid drops
Soft gels
Gummies
Powders
Food Sources of Krill Oil
While it’s possible to buy canned and frozen krill meat, it’s not commonly found in grocery stores. For other sources of omega-3 fatty acids, you can eat cold-water fatty fish like:
Salmon
Trout
Herring
Mackerel
Sardines
Try to up your seafood game before you think about taking a krill oil supplement, Kimberlain says. “I always suggest a food-first approach,” she says. If you don’t eat seafood, you can also get omega-3s from flaxseed, chia seeds, and walnuts.
How to Select and Store Krill Oil
Use these tips when shopping for and storing krill oil supplements.
Look for Third Party–Tested Brands
When choosing a krill supplement, look for brands that have been tested by independent organizations, such as NSF International, ConsumerLab.com, or U.S. Pharmacopeia (USP). This means the product has undergone third-party testing for quality and purity.
Also, check where the krill oil supplement has been sourced. “The best krill supplements are thought to be of Antarctic origin, as these carry a lower risk of contaminants,” says Kamely. She recommends choosing a krill oil supplement that is transparent about information on the oil’s origin and harvesting practices. Consider buying brands that carry the following sustainability certifications:
Supplement makers often recommend storing krill oil somewhere cool and dry. But follow the storage instructions for your specific supplement.
Proper Dosage of Krill Oil
“There isn’t enough research to determine a set amount of krill oil to take daily,” says Kimberlain. But the FDA recommends that the daily intake of EPA and DHA combined does not exceed 3 g per day, with no more than 2 of those grams coming from supplements.
Talk to your doctor before taking a krill oil supplement, especially if you:
Are allergic to seafood
Take blood thinners
Have a bleeding disorder
Are preparing for surgery
Are pregnant or breastfeeding
If your doctor gives you the go-ahead, follow their specific dosage instructions.
The Takeaway
Most Americans don’t get the two weekly servings of fish or seafood recommended in the U.S. Dietary Guidelines, which may mean they’re missing out on omega-3 fatty acids.
Krill oil is a source of omega-3 fatty acids, which may benefit heart health, joint and menstrual pain, and inflammation. More research is needed to fully understand the potential benefits of krill oil.
Krill oil supplements may not be recommended if you have allergies to fish and seafood, are taking blood thinners, have a bleeding disorder, are preparing for surgery, or are pregnant or breastfeeding.
Talk to your doctor before starting krill oil or any other types of supplements.
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
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A Look at Krill Oil’s Benefits. Cleveland Clinic. November 17, 2021.
Banaszak M et al. Role of Omega-3 Fatty Acids Eicosapentaenoic (EPA) and Docosahexaenoic (DHA) as Modulatory and Anti-Inflammatory Agents in Noncommunicable Diet-Related Diseases – Reports From the Last 10 Years. Clinical Nutrition ESPEN. July 8, 2024.
Mozaffarian D et al. Effectiveness of a Novel ω-3 Krill Oil Agent in Patients With Severe Hypertriglyceridemia. JAMA Network Open. January 6, 2022.
Huang H et al. Clinical Effectiveness of Krill Oil Supplementation on Cardiovascular Health in Humans: An Updated Systematic Review and Meta-Analysis of Randomized Controlled Trials. Diabetes & Metabolic Syndrome: Clinical Research & Reviews. December 2023.
Bjørklund G et al. The Role of Astaxanthin as a Nutraceutical in Health and Age-Related Conditions. Molecules. October 23, 2022.
Liu F et al. Phospholipid-Rich Krill Oil Promotes Intestinal Health by Strengthening Beneficial Gut Microbial Interactions in an Infectious Colitis Model. Food & Function. March 4, 2024.
Liu F et al. Mechanistic Insights Into the Attenuation of Intestinal Inflammation and Modulation of the Gut Microbiome by Krill Oil Using In Vitro and In Vivo Models. Microbiome. June 4, 2020.
Stonehouse W et al. Krill Oil Improved Osteoarthritic Knee Pain in Adults With Mild to Moderate Knee Osteoarthritis: A 6-Month Multicenter, Randomized, Double-Blind, Placebo-Controlled Trial. The American Journal of Clinical Nutrition. September 2, 2022.
Sampalis F et al. Evaluation of the Effects of Neptune Krill Oil on the Management of Premenstrual Syndrome and Dysmenorrhea. Alternative Medicine Review. May 2003.
Lobo PCB et al. Krill Oil Supplementation Does Not Change Waist Circumference and Sagittal Abdominal Diameter in Overweight Women: A Pilot Balanced, Double-Blind, and Placebo-Controlled Clinical Trial. International Journal of Environmental Research and Public Health. October 20, 2022.
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Kara Andrew, RDN, LDN, is the director of health promotion for Memorial Hospital in Carthage, Illinois. She is also licensed as an exercise physiologist and certified in lifestyle medicine by the American College of Lifestyle Medicine. Her experience includes corporate wellness, teaching for the American College of Sports Medicine, sports nutrition, weight management, integrative medicine, oncology support, and dialysis.
She earned her master's in exercise and nutrition science at Lipscomb University.
Andrew has served as a president and board member of the Nashville Academy of Nutrition and Dietetics. She was recently elected a co-chair of the fitness and medicine group in the American College of Lifestyle Medicine.
Leslie Barrie is a health and nutrition writer and editor who loves running marathons and attempting to cook healthy meals for her family (even if they don’t always turn out as planned). She received her bachelor of science degree at UCLA and her master of science degree at the Columbia University Graduate School of Journalism. She has written and edited for publications like Health magazine, Seventeen, and Woman’s Day. Leslie won a Hearst Spotlight Award for her work in 2018 at Woman’s Day, and helped plan the Woman’s Day Red Dress Awards, an event honoring changemakers fighting to end heart disease in women.
When she isn’t writing, Leslie loves chasing her daughter and son around outside, going on family hikes, and starting her day with a big bowl of muesli.
Jessica Migala is a freelance writer with over 15 years of experience, specializing in health, nutrition, fitness, and beauty. She has written extensively about vision care, diabetes, dermatology, gastrointestinal health, cardiovascular health, cancer, pregnancy, and gynecology. She was previously an assistant editor at Prevention where she wrote monthly science-based beauty news items and feature stories.
She has contributed to more than 40 print and digital publications, including Cosmopolitan, O:The Oprah Magazine, Real Simple, Woman’s Day, Women’s Health, Fitness, Family Circle, Health, Prevention, Self, VICE, and more. Migala lives in the Chicago suburbs with her husband, two young boys, rescue beagle, and 15 fish. When not reporting, she likes running, bike rides, and a glass of wine (in moderation, of course).
