Ask an Expert: Are All Fish Oils the Same?




With countless fish oil supplements available on the market making similar claims, you may feel inclined to purchase a cheaper fish oil, thinking that one fish oil supplement is as good as any other. However, not all fish oils are the same. In fact, when comparing a range of fish oil supplements, the differences in quality can be significant.

       >> Watch short video on how to tell the quality of a fish oil

There is a large body of research demonstrating the multiple health benefits of omega-3 essential fatty acids. Research also confirms that many people worldwide are lacking in this nutrient and looking to supplement with a high-quality omega-3 product. Here are some of the key factors to consider when choosing an omega-3 fish oil supplement:

Molecular Form

In fish, the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) naturally occur in the triglyceride molecular form. When a high-quality, concentrated fish oil supplement is produced, each of the three fatty acid chains of molecules gets removed from its glycerol backbone. These delicate fatty acids are then stabilised by binding them to an ethyl alcohol molecule. Thereafter, they are molecularly distilled as a means of purification, and in order to raise the concentration of both EPA and DHA.

Upon achieving the desired concentration, an omega-3 manufacturer has two choices. They can:

1) Re-attach the fatty acids to the glycerol backbone via the process of re-esterification—this leading-edge technology recreates the triglyceride structure, and ensures that the fish oil is best absorbed and utilised in supplement form.


2) Leave the fish oil as an ethyl ester, a man-made form of fatty acid molecule that occurs nowhere in nature. This is the cheaper option, but means that less of the essential fatty acids are absorbed by the human body.

Type of fish

A high-quality fish oil requires high-quality raw material. Look for fish oil supplements that use wild Arctic cod (Skrei) from Norway. Alongside its high omega-3 content, Arctic cod is rich in vitamins A and D, which offer additional health benefits.


The looming extinction of many fish species is not something to be overlooked, so it is important to ask whether the fish oil supplement you recommend is from a sustainable source. One question we should ask is: Were the fish sourced with smaller boats and independent fisherman, or large trawling vessels? Smaller boats are ideal, as the latter spend more time at sea, and are more likely to use unsustainable practices to catch their fish. Ultimately, a supplement company that works with independent fisherman is working to maintain fish sustainability—and the quality of their fish oil—while also supporting smaller businesses.

Transport Time

The freshness of the raw material is largely determined by the transport time between when the fish are caught, and their delivery to the processing facility. The shorter the transport time, the better. A reputable fish oil manufacturer will ensure optimum freshness by using processing facilities close to, or on the harbour where the boats return with their catch.

Manufacturing Processes

Maintaining the quality of fish oil extends beyond fishing practices and transport. The use of nitrogen is also essential in bottling facilities to ensure minimal oxygen exposure throughout processing. This helps prevent oxidative rancidity, the cause of the ‘fishy’ odour, taste, and aftertaste associated with poor quality fish oil products. Such products may decrease patient compliance, and raise cellular oxidation when administered to patients.

Purity of the Fish Oil

Another factor to consider is whether the fish oil supplement contains environmental toxins. Has the fish been sourced from clean or polluted waters? Is the fish naturally low or high in toxins like mercury? Regardless of these factors, all fish oils require purification prior to being used in omega-3 supplements. Leading manufacturers ensure that their fish oil products meet the fish oil safety and purity standards established by organisations such as:

  • The Council for Responsible Nutrition
  • European Pharmacopeia Standard
  • The Global Organisation for EPA and DHA Omega-3 (GOED)

Third-Party Testing

Product testing by independent organisations is the only way to get an objective confirmation of the quality of the fish oil. However, it is inadequate for just a single batch of oil to be third-party tested for the manufacturer; to ensure optimum levels of purity and freshness in all products you recommend, third-party testing is needed on every batch of fish oil. Most reputable manufacturers will offer the results of these tests to customers, so make sure you ask.

High-Quality Studies

Research institutions such as the U.S. National Institutes of Health (NIH) select only high-quality fish oils for their studies on the benefits of omega-3 for varying health conditions, ranging from brain health to cardiovascular health. It is worthwhile purchasing fish oil from a brand whose product is chosen, without solicitation, for omega-3 research. This indicates that their fish oil is of the highest quality when it comes to purity and freshness.

Clearly, not all fish oils are created equal. When it comes to buying an omega-3 fish oil supplement, you get what you pay for.

About the Author

With over twenty years experience in the field of Nutritional Medicine,
Stuart Tomc is an authority on evidence-based dietary supplements. He is a respected consultant to the World Health Organization and integrative physicians worldwide having travelled the world as an educator and trainer for over 10 years. With an accomplished background in media appearances, Stuart is adept at educating, entertaining, and delivering a powerful message on important health subjects in today’s changing world.

In addition, he was a contributing writer in Dr. Perricone’s Seven Secrets to Beauty, Health and Longevity by Dr. Nicholas Perricone, and has appeared on almost 50 television shows and exhibited at over 150 natural health and product shows. 

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