The quality of fatty acids in fish oils


Almost everything has been said and written about fish oil and omega-3 fatty acids. There is, however, an issue that is very often overlooked. Indicator of the quality of the fish oil is not only standardizing the content of EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) and correspondingly low content of heavy metals (eg. cadmium, lead, mercury). The Totox index is an equally important factor. To better understand the importance of this indicator, we should look at the biochemical side of omega-3 fatty acids.

Fat saturation

We know very well that fatty acids can differ in the degree of saturation. In general, we can divide them into saturated fatty acids, monounsaturated and polyunsaturated ones [1]. As a general rule, the more multiple bonds in a fatty acid molecule, the more susceptible it is to oxidation reactions. As a result of the oxidation process, a variety of undesirable products are created, which eventually significantly affects the quality of the oil, and can negatively affect our health. Factors that favour the oxidation of fatty acids include improper production process, high temperature and exposure to sunlight [2].

Chemistry of omega-3 fatty acids

Fish oils are most often standardized for EPA and DHA content. It is these acids that are largely responsible for the pro-health benefits. These compounds, due to their chemical structure, show the greatest tendency to oxidize. As mentioned earlier: the more multiple bonds, the easier the oxidation processes occur [3].

EPA and DHA fatty acids - chemical structure
EPA and DHA fatty acids - chemical structure

As a result of the oxidation of omega-3 acids, compounds such as peroxides and highly reactive free radicals are be formed, which are responsible for e.g. initiating mutagenesis and carcinogenesis processes [4].

Totox as a determinant of fish oil quality

After determining the amount of primary (peroxide value) and secondary (anisidine value) oxidation products, we are able to determine the Totox value [5]. In short: the higher the Totox value, the lower the quality of the oil. To better illustrate this issue, we can compare the most popular supplements on the market.


Totox value
Apollo's Hegemony Ultra Fish Oil 6.0 [6]
Manufacturer 1 7.91 [7]
Manufacturer 2 17.40 [7]
Manufacturer 3 21.66 [7]
Manufacturer 4 21.08 [7]


According to EFSA standards, products rich in omega-3 acids should show a Totox value lower than 25 (Totox <25) [8]. All of the above products meet the EFSA requirements, but there are clearly differences in the quality of the supplements offered. Only one of the leading manufacturers showed a Totox value comparable to Apollo's Hegemony product. To sum up: when choosing a fish oil, it is worth considering not only the content of EPA and DHA or the content of heavy metals. We have to take into account an additional factor, which is the Totox value. Remember – the lower, the better! It should be noted that In the case of Ultra Fish Oil Apollo's Hegemony, additional research was carried out that confirm the high quality of this product.


  • Svendsen, K., Arnesen, E., & Retterstøl, K. (2017). Saturated fat - a never ending story? Food & Nutrition Research, 61 (1),
  • Hădărugă, DI, Ünlüsayin, M., Gruia, AT, Birău (Mitroi), C., Rusu, G., & Hădărugă, NG (2016). Thermal and oxidative stability of Atlantic salmon oil (Salmo salar L.) and complexation with β -cyclodextrin. Beilstein Journal of Organic Chemistry, 12, 179–191.
  • Ismail, A., Bannenberg, G., Rice, HB, Schutt, E., & MacKay, D. (2016). Oxidation in EPA- and DHA-rich oils: an overview. Lipid Technology, 28 (3–4), 55–59.
  • Mińkowski, K., Grześkiewicz, S., Krupska, A. (2012). Application of the HS-SPME_GC / FID method to detect early oxidative changes in linseed oil. Food. Science. Technology. Quality, 6 (85), 93 - 102.
  • Wroniak, M., Kwiatkowska, M., Krygier, K. (2006). Characteristics of selected cold pressed oils. Food . Science. Technology. Quality , 2 (47), 46 - 58
  • Test report No. 298636/20/SGDY (Hamilton)
  • The results of research conducted as part of the "Badamy suplementy" initiative
  • Scientific Opinion on Fish Oil for Human Consumption. Foo d Hygiene, including Rancidity EFSA Panel on Biological Hazards (BIOHAZ), European Food Safety Authority (EFSA), Parma, Italy . EFSA Journal 2010; 8 (10): 1874.

Tags: apollo's hegemony, dha, epa, omega-3, totox, ultra fish oil

Leave a Comment

Your email address will not be published. Required fields are marked *