What is TOTOX in fish oil?

Last reviewed September 2026 — every IFOS certificate link on this site re-checked and resolving. Figures cited to public IFOS certificates; the GOED limit is cited to the GOED voluntary monograph.

GOED's voluntary monograph sets a maximum TOTOX of 26 for finished fish oil. The 10 products on this site with a published TOTOX measure 3.49 to 17.74 — every one inside that limit, read from its own public certificate.

→ See which fish oils actually test fresh — TOTOX from the public IFOS certificate, next to measured EPA+DHA and cost per gram.

TOTOX (total oxidation value) is a single number for how oxidized — how rancid — a fish oil is. Fish oil is fragile: heat, light, and time turn its omega-3s into oxidation by-products that taste and smell off and degrade quality. TOTOX is the standard way that number gets reported on a third-party test.

How TOTOX is calculated

It combines two lab measurements:

Peroxide Value (PV) — primary oxidation (early-stage).
Anisidine Value (AV) — secondary oxidation (later-stage breakdown).

The formula is TOTOX = 2 × PV + AV. Because it captures both stages, a low peroxide value alone can't hide an oil that's already broken down further — which is why TOTOX is more honest than PV by itself.

What counts as fresh?

The Global Organization for EPA and DHA Omega-3s (GOED) sets a voluntary maximum of 26 for finished fish oil in its voluntary monograph. In practice, well-made products test far lower. On our ranking we flag anything under 5 as "fresh," 5–10 as acceptable, and higher as a concern — a stricter bar than the industry ceiling, because you can afford to be picky when the data is public.

Why we put TOTOX next to price

A bottle can be cheap because the oil is old or poorly stabilized. Ranking on price alone rewards that. By showing the IFOS-tested TOTOX in the same row as cost-per-gram, cheap-but-rancid can't win on a technicality. The two IFOS-certified numbers most worth reading together are cost per gram of actual EPA+DHA and TOTOX.

How to check any product yourself

Every row in our table links that product's certificate page here, and each of those pages links the IFOS certificate PDF itself — so it is two clicks to the source, not one. The stability section of the PDF lists Peroxide, Anisidine and TOTOX for the tested lot. You don't have to take our word for the number: open the certificate and read it. Every certificate link on this site was re-checked on 4 September 2026 and all of them resolve.

TOTOX is a freshness indicator, not a health claim. This page explains a published laboratory metric and does not diagnose, treat, or make any claim about health outcomes.