Krill Oil

Medically Reviewed by Christine Mikstas, RD, LD on June 05, 2023
Written by R. Morgan Griffin
3 min read

Krill oil comes from krill, tiny shrimp-like creatures that live in very cold ocean waters. Studies show that krill oil might have health benefits similar to those of fish oil.

Krill oil contains EPA and DHA, the same omega-3 fatty acids in fish oil, although usually in smaller amounts. The effects of krill oil have not been researched as thoroughly as those of fish oil. But a few preliminary studies suggest that krill oil could be superior in some ways. Krill oil might be better absorbed in the body than fish oil.

One small study found that krill oil, like omega-3s in general, could improve rheumatoid arthritis and osteoarthritis symptoms such as pain, stiffness, and functional impairment. It also lowered levels of C-reactive protein, a marker for inflammation in the body that's been linked with heart disease.

In addition, krill oil eased symptoms of premenstrual syndrome in another small study.

Because some studies indicate that the fatty acid DHA may benefit a developing child’s brain, krill oil is sometimes taken by pregnant women or given to children. Experts do not recommend this, however, since safety or efficacy of krill oil in pregnant women and children has not been proven.

As krill oil becomes more popular, some scientists are concerned about the environmental impact of large-scale krill harvesting. Krill are an important food source for many animals, including whales, seals, and penguins and other birds.

Since krill oil is not an established treatment, there's no standard dose. Talk to your healthcare provider to see if krill oil is right for you.

The only source of krill oil is krill.

  • Side effects. Krill oil seems to cause few side effects. Some people might have gas, bloating, or diarrhea.
  • Risks. Check with a doctor before using krill oil if you have a bleeding disorder or a seafood allergy. Krill oil can slow blood clotting, and shouldn’t be taken for two weeks before surgery. If you are pregnant or nursing, talk to your health care provider before taking krill oil.
  • Interactions. If you take any medicines regularly, talk to your doctor before you start using krill oil supplements. Like other omega-3 fatty acids, krill oil may cause an increased risk of bleeding and should be used with caution, especially if you are taking anticoagulant medications (blood thinners). Since krill oil interferes with the blood's ability to clot, it could interact with medicines such as blood thinners and anti-platelet drugs. The same risks might apply to taking krill oil while using supplements such as ginkgo biloba, garlic, and ginger. Its absorption may also be affected by certain weight loss drugs. Krill oil may lower blood glucose levels, so talk to your doctor before using if you take any medicines for diabetes.