Home Omega 3 Tests show omega 3 sold in NZ is oxidised, be assured –...

Tests show omega 3 sold in NZ is oxidised, be assured – our OmegaRx is NOT


A recent study has been widely publicised:

Fish oil supplements in New Zealand are highly oxidised and do not meet label content of n-3 PUFA


Received Accepted Published

Key points from this study:

  • Quality and content of fish oil supplements in New Zealand was tested in 32 products available for sale in NZ
  • All encapsulated fish oil supplements marketed in New Zealand were eligible for inclusion.
  • Fatty acid content was measured by gas chromatography.
  • Peroxide values (PV) and anisidine values (AV) were measured, and total oxidation values (Totox) calculated. (These are measures for oxidation i.e. rancidity)
  • Only 3 of 32 fish oil supplements contained quantities of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) that were equal or higher than labelled content, with most products tested (69%) containing <67%.
  • The vast majority of supplements exceeded recommended levels of oxidation markers. 83% products exceeded the recommended PV levels, 25% exceeded AV thresholds, and 50% exceeded recommended Totox levels.
  • Only 8% met the international recommendations, not exceeding any of these indices.

Almost all fish oil supplements available in the New Zealand market contain concentrations of EPA and DHA considerably lower than claimed by labels. Importantly, the majority of supplements tested exceeded the recommended indices of oxidative markers. Surprisingly, best-before date, cost, country of origin, and exclusivity were all poor markers of supplement quality.

Here is a graph showing the missing Omega 3 EPA and DHA

The actual n-3 PUFA content (EPA + DHA) contained in individual retail fish oil products in relation to the claimed content (dotted line).

These graphs show the oxidation levels in the fish oil capsules. Total oxidation values (Totox) 

The content of oxidation markers in retail fish oil tested in relation to recommended international thresholds (dotted lines).

This is unacceptable. There has been criticism of this study, for example methods of testing oxidation were questioned. You can read more here:

UPDATED: Fish oil capsules fall short on quality, freshness – experts respond

How do you ensure omega 3 fish oil is free from oxidation?

Eating fresh fish is one way to be sure you don’t consume omega 3 that is oxidised. The other is to buy fish oil which is tested to a high level, batch tested AFTER it has been encapsulated. This is important, as the process of moving the liquid fish oil into capsules can cause it to become oxidised.

The omega 3 I sell to New Zealanders is Zone OmegaRx. It is tested to the highest standards, IFOS, and every batch of capsules is tested after it has been encapsulated. It is tested for purity, strength and oxidation levels.

Here are the reports on different fish oils that anyone can access: http://www.nutrasource.ca/ifos/consumer-reports/

Here is a print of the most recent batch of OmegaRx capsules

IFOS omegarx

If you live in New Zealand or Australia – you can purchase OmegaRx here: Zone diet shop, OmegaRx


Our clients repeatedly say – they notice the difference between this product and others off the shelf – a noticeable reduction in inflammation, improved skin,  a boost in energy and better mental focus are typical results.

For US sales go to: http://www.zonediet.com/product-category/omega-3-fish-oil/


Fish oil study: Here is the full table of results FYI – we do not know what brand each fish oil actually is.

Leave a Reply