Krill Oil vs Fish Oil: Ambrosia of the Sea?

 Krill Oil vs Fish Oil

Krill oil and fish oil supplements are two prime sources of omega-3 fatty acids, including DHA and EPA. Comparing krill oil vs fish oil is interesting because it can be important for some people who want to get the best nutritional boost for their money.

Fish oil comes from oily fish, such as tuna, salmon, herring or sardines. Fish oil supplements typically have a yellow or gold color.

cognitive function

Krill oil comes from a tiny crustacean, shrimp-like animal called krill.  Krill oil supplements have a distinctive reddish color which comes from a naturally occurring antioxidant called astaxanthin.


Several different omega-3s exist in nature, but the majority of scientific research focuses on three: alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). On the molecular level ALA contains 18 carbon atoms. EPA and DHA are considered “long-chain” (LC) omega-3s because EPA contains 20 carbons and DHA contains 22.


long chain omega 3's

ALA is present in plant oils, such as flaxseed, soybean, and canola oils. DHA and EPA are present in fish, fish oils, and krill oils, however they are originally synthesized by microalgae, not by the fish. When fish consume phytoplankton that have consumed microalgae, they accumulate the omega-3s in their tissues.


Benefits of Krill Oil and Benefits of Fish Oil

Both fish oil and krill oil supplements contain omega-3 fatty acids. Some of the most popular and beneficial omega-3 fatty acids are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

When a person consumes these fatty acids in fish, they demonstrate supportive effects on overall heart health and a reduction in the risks of heart attack and coronary artery disease.

Plant-based sources of omega-3s from algal oil usually provide around 100–300 mg DHA; some contain EPA as well. These supplements typically contain omega-3s in the triglyceride form. According to a small study, the bioavailability of DHA from algal oil is equivalent to that from cooked salmon

Krill oil omega 3s are primarily structured as phospholipids, and limited research even suggests that these have higher bioavailability than the omega-3s in fish oil.



Serenity Health sells a Krill Oil supplement.

While research has shown eating whole fish can have heart-protecting benefits, scientific studies have not yet proven that taking omega-3 supplements offers the same benefits as eating fish.

salmon omega 3's


What can omega-3s do for you? Fish oil and krill oil benefits are indeed remarkable.

  • Reduce high triglyceride levels. High triglyceride levels have links to an increased risk for heart disease.
  • Relieve joint pain and rheumatoid arthritis. Evidence suggests that omega-3 supplements may help relieve the symptoms of rheumatoid arthritis.

joint pain

  • Relieve dry eye symptoms. Some people use omega-3 supplements to help improve eye moisture and reduce the symptoms of dry eye disease. However, large-scale studies have found that taking omega-3 supplements are no better than a placebo for eye dryness, so more research is necessary.

dry eye

  • Reduce risk for dementia. Some, but not all, observational studies suggest that diets high in LC omega-3s are associated with a reduced risk of cognitive decline, Alzheimer’s disease, and dementia.


  • Aids visual and cognitive development. High concentrations of DHA are present in the cellular membranes of the brain and retina, and DHA is important for fetal growth and development. The accumulation of DHA in the retina is complete by birth. Accumulation in the brain continues throughout the first 2 years of life after birth.

retina health

  • Reduce risk for Age-Related Macular Degeneration (AMD).  Based on DHA’s presence in retinal cellular membranes and the beneficial effects of EPA on retinal inflammation, researchers have suggested that these omega-3s have protective effects in the retina that may help prevent the development or progression of AMD. Results from studies suggest that people who consume higher amounts of fatty fish and/or dietary long chain omega-3s have a lower risk of developing AMD.
  • The benefits of omega-3 supplementation are currently being investigated for several other conditions, including depression, inflammatory bowel disease, attention-deficit/hyperactivity disorder (ADHD), childhood allergies, and cystic fibrosis.


Serenity Health sells a Krill Oil supplement. 



A study from 2011 compared the effects of fish and krill oil, finding that they resulted in similar blood levels of EPA and DHA. It’s important to point out that the test subjects took 3 grams of krill oil and only 1.8 grams of fish oil.  According to the study's authors, 30–65% of krill oil's fatty acids are stored as phospholipids, while the fatty acids in fish oils are instead stored primarily as triglycerides.  The researchers suggest that the body may able to use fatty acids stored as phospholipids more easily.

The amount and concentration of omega-3 in krill and fish oil can vary depending on the product. Some krill oil manufacturers claim that the krill oil omega-3s are better absorbed than fish oil omega-3s, so a lower concentration works just as well. While there may be some who agree, there is no proof that this statement is true.

Another small-scale study published in 2013 found that after 4 weeks of taking only one of the supplements, krill oil led to higher levels of EPA and DHA in a person's blood compared with fish oil. However, studies are not necessarily consistent. A study from 2015 found no differences in krill oil and fish oil in the blood after 4 weeks of taking supplements.  While some research suggests that the body might better absorb krill oil, other studies find no difference in absorption between fish oil vs krill oil. The search goes on…

fish oil

Fish Oil and Krill Oil side effects:

Taking omega-3 supplements in the forms of krill oil and fish oil does not appear to cause any significant side effects. Minor side effects are, however, possible.

Bad breath




Unpleasant sweat smell

Upset stomach

Additionally, omega-3 supplements have the potential to interact adversely with blood-thinning medications because omega-3 fatty acids have mild anticoagulant (blood-thinning) effects. For this to happen a person must usually take a high dose, between 3 and 6 grams of fish oil per day, for these interactions to occur.

krill nutrition


The evidence is still inconclusive about whether krill oil works as well as or better than fish oil. Most of the research on the benefits of omega-3 fatty acids has been carried out using fish oil.

It is estimated by ODS (Office of Dietary Supplements) that 8% of adults and 1% of children in the United States take omega-3 supplements in the forms of fish oil, krill oil, algal oil or flaxseed oil.

Taking omega-3 supplements can offer benefits by lowering triglyceride levels, maintaining retinal health, reducing cognitive decline and relieving rheumatoid arthritis symptoms. The jury is still out whether they can reduce heart disease or improve overall cardiovascular health equally as eating whole fish.

According to the NIH (National Institutes of Health), eating oily fish (tuna, salmon, sardines and others) can offer a greater variety of nutrients than supplements and has demonstrated improvements in heart health.

Fortifying one’s diet with either fish oil or krill oil supplements can help boost a person's overall levels of omega-3 fatty acids, and that is a good thing. Is one source actually better than the other? Time will tell.

Serenity Health sells a Krill Oil supplement.