New Report Finds Many Common Omega-3 Fish Oil Supplements are Rancid

Omega-3 fish oil supplements are among the most frequently consumed non-vitamin/mineral supplements in the United States. 

According to the National Institutes of Health, about 18.8 million (7.8%) U.S. adults and 664,000 (1.1%) children use fish oil supplements. 

People take Omega-3 fish oil supplements to support their health and wellbeing. 

However, they may not be as safe and harmless as it seems. A recent report by Labdoor revealed many common products of this kind are rancid. Scroll down to learn more.

What are Omega-3 fish oil supplements?

Omega-3 fish oil supplements are non-vitamin/mineral supplements that deliver Omega-3 fatty acids obtained from fish such as anchoveta caught off the coast of Peru and Chile and oily fish such as salmon, mackerel, tuna, and herring. 

Basically, Omega-3s are a family of essential fatty acids the body needs to function properly but doesn’t produce on its own. Three main types of Omega-3s are eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and alpha-linolenic acid (ALA). 

The body needs these essential fatty acids for the proper functioning of the heart, blood vessels, brain, lungs, immune system, and endocrine system. The use of fish oil supplements has become widespread. According to Harvard Medical School, Americans spend over $1 billion a year on these products.

A helpful thing to mention is that American Heart Association recommends eating fatty fish at least twice a week to obtain enough Omega-3 fatty acids. While the goal is to obtain as much as possible through diet alone, many people don’t get sufficient amounts of Omega-3s that way. 

That’s where an Omega 3 supplement steps in. And, as you can presume, fish oil supplements are the most popular tool to supply the body with much-needed fatty acids.

Besides fish oil, good sources of Omega-3 fatty acids are cod liver oil, krill oil, and algal oil. The latter is a vegan-friendly plant-based source of these fatty acids.

The recommended daily dose of Omega-3 fatty acids is a minimum of 250 to 500mg combined DHA and EPA for healthy men and women. 


Many common Omega-3 fish oil supplements are revealed to be ‘rancid’ 

Even though Omega-3 fish oil supplements are among the most popular health-related products, they may have some disadvantages too. Not all products possess the quality you expect. 

Many of them do not, according to research carried out by Labdoor, an independent company that tests dietary supplements based on parameters such as label accuracy, purity, nutritional value, among others. The company aimed to evaluate US-branded fish oil supplements and check their rancidity status. 

The research, carried out between 2014 and 2018, included products made by different brands whose products are easily accessible in retail chains and online. They found that rancidity levels are a lot higher than the suggested limits. Moreover, the rancidity in some fish oil supplements was 11 times higher than recommended 26.

Rancid supplements are often characterized by unpleasant smells and a strong fishy taste. Many brands use flavorings and other additives to mask the rancidity of their products.

These products become rancid due to oxidation. These findings are in line with previous studies. 

For example, a study from Nutrition Reviews discovered that over 20% of fish oil supplements are excessively oxidized. The brands’ flavorings to mask rancidity tend to make oxidized supplements more palatable. In other words, they also hide the fact these supplements are excessively oxidized. 

Although oxidation is a normal process, fish oil is particularly susceptible to it. The main factor here is a long chain of supply.

The health impact of rancid supplements

The health impact of rancid or oxidized fish oil supplements is unclear. But some studies have shown they could have negative effects. 

A study from the British Journal of Nutrition compared high-quality and oxidized fish oil supplements. Results showed that quality plays a major role in the effects of these products. Oxidized fish oil has a negative influence on cholesterol levels. 

According to a study from the American Physiological Society, high doses of oxidized fish oil supplementation could have toxic effects.

The concerns with some fish oil supplements

Today’s biggest problem with some Omega-3 fish oil supplements is high rancidity and oxidation. Even though more research on this subject is necessary, oxidation could change how the product works. In other words, you may not be able to get everything Omega-3 fatty acids provide in rancid and excessively oxidized fish oil supplements. 

A paper from the Journal of Nutritional Science explains that the oxidation of fish oil supplements is complex. Various factors affect the degree and rate of oxidation. Some of these factors are fatty acid composition, exposure to light and oxygen, antioxidant content, temperature, and presence of heavy metals and water.

The Current Opinion in Lipidology explained that fish oil supplements are classified as food by the FDA, so they do not go through rigorous clinical testing. This explains why many products on the market are high in rancidity and are oxidized too much. 

However, many people often use fish oil supplements hoping they can help them normalize blood lipid levels to improve heart health. But, this paper confirmed that heavily oxidized fish oils also contain saturated fat that can contribute to dyslipidemia. And, as a result, they may not be a good solution for persons who want to manage or prevent their heart disease

This can be particularly inconvenient for persons who turn to fish oil dietary supplements as a healthy addition to their lifestyle to prevent a heart attack

Besides these problems, the fish oil pill is also associated with “fishy burps” and side effects such as loose stools, heartburn, and nosebleed.


While it’s easy to think that the best fish oil supplements may not be so problematic, the truth is that they can be. As discussed above, many products of this kind on the market could have high rancidity, but brands know how to conceal it to make this problem less noticeable. 


Fish oil vs. krill oil supplements 

The body needs Omega-3s for good health and wellbeing. Most people don’t get enough through diet alone. But, fish oil is not the only manner of Omega-3 fatty acids supplementation. 

Krill oil supplements are also a viable option. You can recognize krill oil thanks to its distinctive reddish color, whereas fish oil is golden yellow. 

Omega 3

Krill oil is oil obtained from Antarctic krill (Euphausia Superba), a small shrimp-like crustacean found in the cold waters of the ocean. Krills are also abundant in Omega-3 fatty acids and are known for their outstanding health benefit.

Since both fish and krill oil contain Omega-3s, it’s impossible not to wonder how they compare to one another. The truth is that fish oil has higher levels of DHA and EPA than krill oil. 

However, these Omega-3 fats in krill oil are more abundant in antioxidants. The body absorbs EPA and DHA from krill oil more efficiently. Since krill oil improves DHA delivery to the brain, lower amounts are necessary to obtain health benefits. 


In addition to stronger antioxidant content, krill oil has other advantages too. It’s a lot safer than fish oil supplements. 

As seen in this post, many fish oil products on the market are rancid and excessively oxidized. Oxidization affects the effectiveness of fish oil to a certain extent, depending on various factors. 

A krill oil supplement is more reliable in this aspect. It is more stable than fish oil and lacks the fishy taste and smell. 


The very sourcing of the fish or krill plays a role in the quality of these supplements. Fish oil is sourced from different kinds of fish. 

In most cases, low-quality fish is used because it’s cheaper to process and extract oil. As a result, this type of oil can be more rancid, and you’re more likely to have indigestion. 

On the other hand, krill oil is sourced from krill only. These tiny sea animals live in a specific area only. That means the obtained oil comes from a sustainable and unpolluted source. For that reason, the quality of that oil is a lot higher.


It’s also useful to mention krill oil is a good source of fat-soluble vitamins, including vitamin D, vitamin A, and vitamin E

Regular supplementation with krill oil can improve heart health, support brain function, and allow you to obtain all the benefits from Omega-3 fatty acids. It’s all thanks to its high purity and quality. 

Our Antarctic Krill Oil Supplement

Ben’s Antarctic Krill Oil is a product extracted from small, red crustaceans called Antarctic krill. These are small shrimp-like crustaceans that live in the clear, pure Antarctic waters.

As a result, krill from which the oil is sourced is unpolluted and sustainable (and comes with no fishy aftertaste).

Many of our customers report being more mobile and agile, experiencing less joint pain, and feeling better about their overall health.

krill oil supplement

Benefits of Our Krill Oil Supplement

  • Source of healthy fats
  • Fights inflammation 
  • Alleviates joint pain
  • Can improve heart health
  • Boosts your immune system
  • Lowers blood pressure and cholesterol
  • Improves memory and focus
  • No fishy aftertaste

Is our Antarctic Krill Oil supplement safe to take?

We are committed to sourcing our products and choosing our partners, in an environmentally friendly and sustainable way.

When it comes to the ingredients in our products, we rigorously test them to ensure that they meet the American pharmacological standards and the American herbal products association standards.

Our manufacturing facilities are all US-based and FDA monitored.

We also go one step further. All finished products are tested by a third-party laboratory using United States pharmacopeial test 1119 (near-infrared spectrography) to ensure that the supplement matches the label and that they are safe, pure, and high quality.

All of our formulations are formulated with 100% natural earth-grown nutrients, and we never use artificial fillers, bulkers, or synthetic vitamins. We always use the most bioavailable form of the nutrient, and whenever possible we use organic ingredients.

Why Choose Ben’s Natural Health Supplements?

At Ben’s Natural Health, our motto is to combine holistic healing with modern science.

Ben’s Natural Health is the world’s first high-quality, all-natural, scientifically proven clinical supplement company. Our supplements are effective, natural, and 100% side-effect-free.

Moreover, at Ben’s Natural Health, we have four rules for all our supplements:

  • We only use the highest quality ingredients
  • We only use them if independent, peer-reviewed double-blind studies prove they work
  • With all our supplements, we find a way to get every ingredient into a single bottle
  • We always formulate them in clinically significant doses of the most bioavailable form

We pride ourselves on offering excellent customer service. We offer a free health consultation where you can ask questions and receive tailored advice from our expert health consultants. 


Research by Labdoor revealed many fish oil supplements on the market are rancid because they are oxidized. Although the health effects of high rancidity are unclear, studies reveal oxidation could change how the supplement works. 

Many brands use additives and flavorings to cover the signs of rancidity. Krill oil emerges as a safer, more reliable, and high-quality method of Omega 3 fatty acid supplementation.

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  1. Vidit V Satokar, Wayne S Cutfield, David Cameron-Smith, Benjamin B Albert, Response to Bannenberg and Rice, Nutrition Reviews, Volume 80, Issue 1, January 2022, Pages 138–140.
  2. Rundblad A, Holven KB, Ottestad I, Myhrstad MC, Ulven SM. High-quality fish oil has a more favourable effect than oxidised fish oil on intermediate-density lipoprotein and LDL subclasses: a randomised controlled trial. Br J Nutr. 2017.
  3. Albert BB, Vickers MH, Gray C, Reynolds CM, Segovia SA, Derraik JG, Lewandowski PA, Garg ML, Cameron-Smith D, Hofman PL, Cutfield WS. Oxidized fish oil in rat pregnancy causes high newborn mortality and increases maternal insulin resistance. Am J Physiol Regul Integr Comp Physiol. 2016. 
  4. Cameron-Smith D, Albert BB, Cutfield WS. Fishing for answers: is oxidation of fish oil supplements a problem?. J Nutr Sci. 2015;4:e36. Published 2015 Nov 23.
  5. Sherratt SCR, Lero M, Mason RP. Are dietary fish oil supplements appropriate for dyslipidemia management? A review of the evidence. Curr Opin Lipidol. 2020;31(2):94-100.

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