Know Your Fish Oil Supplements

By Dr Ernst
December 21, 2016

Media exposure, scientific findings, and word of mouth have lead to a significant increase in fish oil supplementation over the past 5 years. And that’s fantastic, because there are real benefits to taking good fish oil supplements. But the popularity of these supplements has also lead to an increased concern over product quality.

The terms “pharmaceutical quality” or “pharmaceutical grade” is typically associated with higher quality fish oils. However the use of this term is not regulated and can be freely used by any branded fish oil product. Most industry experts associate pharmaceutical quality and pharmaceutical grade with products that comply with a fish oil monograph developed by the Council for Responsible Nutrition (CRN). Compliance with the CRN monograph does not necessarily mean that a product is of the highest quality, but it’s a step in the right direction.

The CRN fish oil monograph was an important step forward in creating stringent quality and purity standards for fish oil supplements, but there are still some quality parameters it does not address, namely the manipulation of omega molecules to make a half-synthetic form of the supplement.

One of the most controversial and debated quality issues not addressed by the CRN monograph is the fish oil’s molecular form – Ethyl Esters or Triglycerides.

What are triglycerides?

Triglycerides (TG) are the natural molecular form that fats are typically found in most food sources. For instance, the omega-3 fats present in all fish species are almost exclusively present as TGs. TGs are fats that are comprised of three fatty acids (i.e. EPA and DHA) linked to a molecule of glycerol. Free fatty acids are rapidly oxidized and therefore the glycerol backbone helps to stabilize the fat molecules and prevent breakdown and oxidation so your body has time to use it. And that’s what you want.

What are ethyl esters, and how are they produced?

Ethyl esters (EE) are an alternate form of fats that are synthetically derived by reacting free fatty acids with ethanol (alcohol). During the processing of some fish oils, the fatty acids are cleaved from their natural glycerol backbone and then esterified (which essentially means bound to) with a molecule of ethanol. This process, called trans-esterification, results in a product called fish oil EEs, also commonly known as Fatty Acid Ethyl Esters (FAEE).

The production of EE fish oils is required for the concentration of long chain omega-3s. The fish oil EEs are heated in a vacuum in a process referred to as molecular distillation, or short path evaporation. The process selectively concentrates the longer chain polyunsaturates resulting in an oil with a higher concentration of both EPA and DHA. This EE concentrate is typically the end product that is sold and marketed as an “omega-3 fish oil concentrate.” The proper term for EE fish oils is “semi-synthetic,” referring to the fact that both ethanol and fatty acids are natural. However, the esterification of these two substances is not found in natural food sources of omega-3 fats.

Basically, fat molecules are manipulated so as to concentrate the active ingredient so it can be put in a pill and marketed as “omega-3 fish oil concentrate.” But it’s not the same and it’s not as good.

How can I determine if my fish oil is a natural triglyceride or an ethyl ester?

There is a simple, inexpensive and rapid method to determine if a fish oil is in the TG or EE form by using polystyrene (Styrofoam) cups.


1. Measure and place 20ml of fish oil in a polystyrene cup. Place the cup on a plate to avoid any mess.

2. Observe the cup after 10 minutes. If the fish oil has leaked significantly through the cup it contains EEs.

Due to their chemical composition, EE fish oils will actually eat straight through the polystyrene cup. This effect will become evident after just a few minutes, however significant leakage is seen after 10 minutes. Natural TG fish oils placed in the same cup will not show leakage after 10 minutes. Natural TG fish oils may show leakage through the cup in very small amounts after 2-3 hours.

Do that once with a brand of fish oil you’re thinking about using and you can rest easy knowing about the quality and effectiveness of your choice.

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