The Battle Against Oxidation: Assessing the ‘Freshness’ of Consumer Marine- and Plant-Derived Omega-3 Supplements


Omega-3 (Ω3) supplements have long been touted for their potential health benefits, ranging from heart health to cognitive function.

These supplements are commonly derived from marine and plant sources and are available in various forms, such as capsules, liquids, and sprays. However, recent studies have shed light on the significant heterogeneity in the ‘freshness’ of these Ω3 supplements, raising concerns about their safety and efficacy.

One of the primary concerns surrounding these supplements is the potential for rancidity or oxidation, which has been the subject of heated debate in scientific literature.

In this article, we delve into a comprehensive study that examines the oxidation levels of 72 consumer Ω3 supplements sold in the United States over a span of six years, from 2014 to 2020. This research is a pioneering effort in assessing the impact of flavoring on the oxidation of Ω3 supplements, while also considering various factors like delivery systems, source, and third-party certifications.

The study reveals startling findings that have significant implications for the health-conscious consumer.

Oxidation in Omega-3 Supplements

Oxidation in Ω3 supplements is a complex chemical process that occurs when the polyunsaturated fatty acids present in these supplements react with oxygen, leading to the formation of harmful compounds such as peroxides and aldehydes. This oxidative process not only alters the taste and odor of the supplements but also reduces their effectiveness and safety.

Oxidized Ω3 supplements may have a detrimental impact on human health, potentially causing inflammation and increasing the risk of chronic diseases.

The Study: Assessing Oxidation Levels

The study in question aimed to assess the oxidation levels in consumer Ω3 supplements, with a particular focus on the impact of flavoring. Researchers analyzed the peroxide value (PV), para-anisidine value (p-AV), and total oxidation values (TOTOX) of 72 supplements. These values are crucial indicators of the freshness and safety of Ω3 supplements.

The supplements were categorized based on various factors:

  • Type of Delivery System: The study considered enteric-coated capsules, liquid forms, animal-derived gelatin softgels, vegetable-derived gelatin softgels, and sprays.
  • Source: Supplements were sourced from algae, calamari, fish, krill, and mussels.
  • Third-Party Certifications: Certifications from organizations like the United States Pharmacopeia (USP) were taken into account.

Flavoring and Oxidation

One of the groundbreaking aspects of this study was its examination of the role of flavoring in the oxidation of Ω3 supplements. The use of flavoring is common in these supplements to improve taste and palatability, but it had not been thoroughly studied in the context of oxidation before.

The Results

The findings of this research are eye-opening. The study revealed that a significant proportion of flavored Ω3 supplements, 68% to be precise, exceeded the TOTOX upper limit set by the Global Organization for EPA and DHA (GOED) voluntary monograph standard of ≤ 26.

Additionally, 65% of flavored supplements failed the PV upper limit of ≤ 5, and a staggering 62% exceeded the p-AV upper limit of ≤ 20. In stark contrast, only 13% of unflavored Ω3 supplements crossed the TOTOX upper limit.

These results suggest that flavoring may play a substantial role in accelerating oxidation in Ω3 supplements. The implications of this finding are profound, especially considering the widespread use of flavored supplements to enhance taste and encourage consistent consumption.

Clinical Implications for Human Health

The oxidation of Ω3 supplements is not merely a matter of taste and odor; it has significant clinical implications for human health. Consuming oxidized Ω3 supplements may lead to the ingestion of harmful compounds that can trigger inflammation and potentially worsen chronic diseases. For individuals seeking the health benefits associated with Ω3 supplementation, consuming oxidized supplements could undermine their efforts and even pose health risks.


The debate surrounding the freshness and safety of consumer marine- and plant-derived Ω3 supplements has gained new momentum with this groundbreaking study. The research highlights the alarming prevalence of oxidation in flavored Ω3 supplements, raising questions about their safety and efficacy.

These findings underscore the importance of careful scrutiny when selecting Ω3 supplements and the need for further research to explore the impact of oxidation on human health.

In the quest for better health through supplementation, the freshness of Ω3 supplements should not be overlooked, as it may make all the difference in achieving the desired health outcomes.

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