Extracted from Antarctic zooplankton Ephausia Superba [1] using a cold vacuum extraction process, krill oil is rich in two Omega 3 fatty acids–EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid)— acknowledged for their antioxidant properties. [2]
Krill oil is touted as a nutritional supplement with health benefits for cognitive function, heart health, anti-aging and general well-being. As a source of Omega 3’s, this supplement can help to correct a dietary imbalance between Omega 6 and Omega 3 fatty acids present in the Western diet.
Krill Oil has received GRAS (Generally Regarded as Safe) status from the FDA and has a low risk of side effects. This product is also considered to have lower risk of side effects compared to Fish Oil, which is more likely to cause stomach upset.
While Krill oil may be safe for healthy adults, some individuals with contradicting health condition should not use this supplement. This is primarily due to the potential for krill oil to negatively interact with certain medications.
There are also low quality products on the market that can pose increased risk of krill oil side effects. There is a possibility that some krill may be contaminated with persistent organohalogen compounds (POCs), chlorinated pesticides and other substances harmful to humans. [3]



- Source of EPA and DHA Omega-3's
- Contains astaxanthin - a potent anti-oxidant
- Supports brain & cardiovascular health
Is Krill Oil Safe?
Related Topics
Krill are tiny crustaceans particularly abundant in the Antarctic Ocean ecosystem.
A major food source for whales, fish and seals [4], krill provides oil with a remarkable “biomolecular profile of phospholipids that is rich in antioxidants and omega-3 fatty acids that differ from the typical profiles of fish oils”. [5]
The DHA and EPA in krill oil appear to benefit fetal development, improve aspects of cardiovascular functioning and may play a role in delaying or reducing the effects of Alzheimer’s disease. [6]
Krill oil also contains astaxanthin, an antioxidant utilized by algae and phytoplankton to repel damaging sunlight and oxygen molecules. In humans, astaxanthin protects cells from potential carcinogens, enhances immune system functioning and inhibits cell damage caused by free radicals. [7]
Investigations into the safe usage of krill oil have found generally positive results. Krill oil dangers mainly involve variables extraneous to the composition of krill oil, such as human allergies to shrimp and/or tropomyosin. [8]
Although krill oil has been deemed “Generally Recognized As Safe” by the U.S. FDA [9], the possibility that some harvested krill oil may have originated from contaminated ocean areas does exist.
Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) found in krill oil has anti-coagulating properties that can inhibit platelet aggregation, especially when taken simultaneously with warfarin. [10] Therefore, those at risk for suffering bleeding complications should always consult with a physician before consuming krill oil.
In addition, the safe usage of krill oil in children, pregnant women and those with serious liver disease have not yet been clinically established.
Common Krill Oil Side Effects
Side effects of krill oil supplements resemble side effects of fish oil supplements. Most of these side effects are caused by the influence of omega-3 fatty acids on the gastrointestinal system.
Possible krill oil side effects include [11]:
- Halitosis (“fishy” breath)
- Upset stomach/nausea
- Heartburn
- Loose stools/diarrhea
- Bloating/indigestion
- Vomiting
- Unpleasant body odor
- Increased appetite
- Dry mouth
- Colitis
Recommended Doses for Krill Oil Supplements
To promote joint, brain and heart health, adults are recommended to take 300 mg of krill oil daily. Taking 1000 to 3000 mg of krill oil daily may help reduce cholesterol, regulate blood glucose, relieve premenstrual syndrome symptoms, improve cognition and even stabilize mood. [12]
Krill Oil Dangers & Interactions
Taking above average doses of krill oil with aspirin, Plavix, Fragmin, heparin, warfarin and other anti-coagulant drugs may increase risk of bleeding or hemorrhaging.
Research shows that krill oil reduces blood glucose levels. [13] Consequently, taking a combination of krill oil supplements and diabetic medications could increase the risk of hypoglycemia.
Randomized controlled trials indicate that krill oil (specifically, the EPA and DHA found in krill oil) lowers systolic blood pressure. Dosages of at least two grams of krill oil lowers diastolic blood pressure. [14] When taken with anti-hypertensive medications, krill oil may therefore enhance the action of these medications and produce unhealthy drops in blood pressure.
Herbal supplements with anti-coagulant/anti-platelet properties (garlic, turmeric, ginger and ginkgo) may increase risk of bleeding when taken with krill oil. Hypoglycemic herbal and nutritional supplements (fenugreek, chromium, alpha-lipoic acid and garlic) may interfere negatively with blood glucose levels.
To date, no krill oil side effects have been reported when taken with food.
Krill Oil vs. Fish Oil Safety
One of the main differences between krill oil, fish oil (omega-3 fatty acids) is that krill oil incorporates a large part of its beneficial fatty acids using phospholipids, which fish oil does not. [15]
Phospholipids constitute vital structures comprising the membranes of all human cell types while also maintaining the healthy functioning and permeability of these cell membranes.
While fish oil is indeed good for the body, certain factors tend to minimize its ability to fully benefit certain physiological systems. Issues emerging with fish oil supplements primarily include possible contamination of fish due to heavy metals (mercury, cadmium and PCBs) and an intensification of the same krill oil side effects experienced by users of krill oil.
In addition, krill are harvested primarily from the Antarctic Ocean, where krill tend to remain in deeper levels. Researchers consider this ocean freer of harmful pollutants than any other ocean in the world. [16]
Fish oil can also cause negative side effects such as a “fishy odor” emanating from the body and “fishy burps” following consumption. These unwanted effects can be mitigated by consuming Fish oil capsules with a meal. However, these adverse effects can also be prevented by using Krill Oil instead.
In conclusion, while Krill Oil is safe for the majority of health adults to take, it may not be appropriate for all users. Speak to your doctor to determine whether this is the appropriate supplement for you to use and whether there are any possible dangers of combining it with other drugs or supplements you are taking.
- http://www.krilloil.ro/cercetari-studii/inflamatii-cronice.pdf
- http://www.ncbi.nlm.nih.gov/pubmed/18848720
- https://www.researchgate.net/profile/Nicholas_Elliott/publication/11016806_A_DNA-based_method_for_identification_of_krill_species_and_its_application_to_analysing_the_diet_of_marine_vertebrate_predators/links/53d78c5e0cf29265323ccf3f.pdf
- http://cre8wellness.co.uk/images/hyperlipidemia_research.pdf
- https://www.researchgate.net/profile/Shaker_Mousa/publication/221830304_Omega-3_fatty_acids_EPA_and_DHA_health_benefits_throughout_life/links/00b7d52179093d2281000000.pdf
- http://www.zentrum-der-gesundheit.de/pdf/astaxanthin-ia_12.pdf
- http://www.ncbi.nlm.nih.gov/pubmed/17912005
- http://www.fda.gov/ucm/groups/fdagov-public/@fdagov-foods-gen/documents/document/ucm269133.pdf
- http://aop.sagepub.com/content/38/1/50.short
- http://www.drugs.com/sfx/omega-3-polyunsaturated-fatty-acids-side-effects.html
- http://naturaldatabase.therapeuticresearch.com/nd/Search.aspx?cs=&s=ND&pt=100&id=1172&fs=ND&searchid=54470570
- https://www.researchgate.net/profile/Rosanna_Chung/publication/26818850_Dietary_krill_oil_supplementation_reduces_hepatic_steatosis_glycemia_and_hypercholesterolemia_in_high-fat-fed_mice/links/0c960514e5e4cbaf17000000.pdf
- http://ajh.oxfordjournals.org/content/27/7/885.full.pdf
- http://www.ncbi.nlm.nih.gov/pubmed/21854650
Article last updated on: March 25th, 2018 by Nootriment
1 Comment
After using fish oil supplements for many years, I tried krill oil. I woke up in the morning with blood all over my pillow. I had no sign of any cuts or wounds and I was perplexed. I took a picture of my pillow and went to the doctor. He looked at some app on his phone and showed me in the doctor’s reference app how bleeding is a fairly common side effect of fish oil products. It can even cause a possibility of stroke. Needless to say I take only recommended dosages of fish oil to this day. More is not better with fish oil.