The Benefits of Krill Oil

Health Benefits, Uses, and More

Antartica krill
David Tipling/Getty Images

Krill oil is an oil that's derived from shrimp-like crustaceans called krill. The omega-3-rich oil contains two of the same essential fatty acids as fish oil (eicosapentaenoic acid, or EPA, and docosahexaenoic acid, or DHA). The EPA and DHA in krill oil are said to have higher bioavailability (rate of absorption) compared to fish oil because much of the EPA and DHA in krill oil is bound to phospholipids.

Found naturally in the ocean, krill are approximately one to six centimeters long and feed mainly on marine phytoplankton which is rich in astaxanthin, a carotenoid pigment that gives krill and other crustaceans such as lobster and shrimps their characteristic red-pink color. Unlike many other antioxidant substances, preliminary studies have found that astaxanthin may cross the blood-brain barrier and protect the brain and central nervous system from free radical damage.

Commercial fishing of krill occurs primarily in the Southern Ocean and the northern Pacific Ocean along the coasts of Canada and Japan. Besides nutritional supplements, commercially fished krill are used for aquaculture and aquarium feeds, sport fishing bait, and for food consumption. In Japan, krill is considered a delicacy and is called okiami.

The recent popularity of krill oil supplements has raised serious concerns that it could threaten the population of its predators, including penguins, seals, and whales. In 2010, Whole Foods Market stopped selling krill oil supplements, citing environmental concerns.

The Health Benefits of Krill Oil

Krill oil is often used for the same reasons as fish oil. Krill oil isn't known to cause a fishy aftertaste or burps, which often happens with fish oil. Also, krill oil contains higher amounts of astaxanthin than fish oil. 

1) High Cholesterol

A study published in Alternative Medicine Review examined 120 people with hyperlipidemia who were given a daily dose of 2-3 g of krill oil, 1-1.5 g krill oil, fish oil (containing 180 mg EPA and 120 mg DHA), or a placebo. Krill oil dosages were dependent on body mass index (BMI). Krill oil (1-3 g per day) was found to be effective for the reduction of total cholesterol, LDL cholesterol, and triglycerides and increasing HDL cholesterol levels compared to fish oil and the placebo.

A 2011 study published in Lipids compared the effects of krill oil (543 mg of combined EPA and DHA), fish oil (864 mg of combined EPA and DHA), or no supplementation on people with normal or slightly elevated cholesterol levels. After seven weeks of supplementation, there was an increase in blood levels of EPA and DHA in both the krill and fish oil groups, but there were no significant changes in any of the blood lipids or markers of oxidative stress and inflammation.

2) Rheumatoid Arthritis

A study in the Journal of the American College of Nutrition examined krill oil (300 mg daily) compared to a placebo and found that supplementation for 30 days with krill oil was effective at reducing symptoms of rheumatoid arthritis and C-reactive protein (a marker of inflammation). Specifically, there was a 20.3-28.9% symptom reduction (assessed by WOMAC) and 31.6% less rescue medication usage.

 3) Premenstrual Syndrome

A study published in Alternative Medicine Review found that 1 g of krill oil twice a day for 90 days resulted in a significant reduction of PMS symptoms measured at days 45 and 90 compared to the group that received fish oil. 

Possible Side Effects

People with allergies to seafood shouldn't use krill oil. Side effects of krill oil may include loose stools, diarrhea or indigestion.

People with bleeding disorders and those taking medication or supplements that may increase the risk of bleeding such as aspirin, warfarin, heparin, clopidogrel, garlic, ginkgo biloba or non-steroidal anti-inflammatory medications (NSAIDS) such as ibuprofen or naproxen should only use krill oil under a physician's supervision. It also shouldn't be taken two weeks before or after surgery.

In general, krill oil supplements haven't been tested for safety and keep in mind that the safety of supplements in pregnant women, nursing mothers, children, and those with medical conditions or who are taking medications have not been established. 

You can get tips on using supplements but if you're considering the use of krill oil, talk with your primary care provider first. 

Was this page helpful?
Article Sources
  • Bunea R, El Farrah K, Deutsch L.Evaluation of the Effects of Neptune Krill Oil on the Clinical Course of Hyperlipidemia. Altern Med Rev. (2004) 9.4: 420-428.
  • Deutsch L. Evaluation of the Effect of Neptune Krill Oil on Chronic Inflammation and Arthritic Symptoms . J Am Coll Nutr. (2007) 26.1: 39-48.
  • Sampalis F, Bunea R, Pelland MF, Kowalski O, Duguet N, Dupuis S. Evaluation of the Effects of Neptune Krill Oil on the Management of Premenstrual Syndrome and Dysmenorrhea. Altern Med Rev. 2003 May;8(2):171-9.
  • Ulven SM1, Kirkhus B, Lamglait A, Basu S, Elind E, Haider T, Berge K, Vik H, Pedersen JI. Metabolic Effects of Krill Oil Are Essentially Similar to Those of Fish Oil but at Lower Dose of Epa and DHA, in Healthy Volunteers. Lipids. 2011 Jan;46(1):37-46. doi: 10.1007/s11745-010-3490-4. Epub 2010 Nov 2.