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Omega-11 (cetoleic acid)

An interesting fatty acid from pelagic fish — with one early human trial, but no established supplement recommendation yet.

Reviewed by Bodil Isaksson, Licensed Biomedical Scientist (Sweden) Last reviewed September 2026

SupplementsFatty acidsOmega-11

Omega-11 is the informal name often used for cetoleic acid (C22:1n-11), a monounsaturated fatty acid found in fatty pelagic fish such as herring. Early research is interesting, but it is far too soon to treat omega-11 as an established supplement.

Key takeaways

  • A first randomised human trial tested a concentrated capsule providing 1,480 mg cetoleic acid/day for eight weeks.
  • LDL cholesterol fell modestly more than with the comparator, with a roughly 7% relative difference.
  • This is one human trial, not yet replicated, and it did not measure heart attacks or strokes.
  • A commercial CETO3 product is an example, not proof that omega-11 supplements work or a general recommendation.

What it is

Cetoleic acid is a long-chain monounsaturated fat naturally present in some fatty pelagic fish, especially herring. It is different from EPA and DHA, the better-established long-chain omega-3 fats in fish oil. The term “omega-11” describes the position of its double bond in the fatty-acid chain.

The human evidence

In an eight-week randomised, double-blind trial of 75 adults with overweight or obesity, a cetoleic-acid concentrate providing 1,480 mg/day was compared with soybean oil. The cetoleic-acid group had a median LDL change of −0.1 mmol/L versus +0.2 mmol/L in the comparator group, a roughly 7% relative difference (p=0.033).1

What it does not show

This is one small human trial, so the result needs replication. LDL cholesterol is a surrogate marker, not a heart-health outcome: no study has shown that omega-11 prevents heart attacks or strokes. An earlier study in rats found larger changes in blood lipids after herring-oil supplementation, but animal results cannot establish a human benefit.2

Product example

CETO3 omega-11 and omega-3 is one commercial product listing. The listing states that four capsules provide 680 mg omega-11, 280 mg EPA and 280 mg DHA; product information can change, so check the packaging. That omega-11 amount is not the same as the 1,480 mg/day tested in the human trial. The link is provided for transparency, not as an endorsement or treatment recommendation.

Bottom line

Promising early lead, not an established supplement recommendation. Eating oily fish such as herring can provide cetoleic acid naturally.

References

Adult research summary for education, not a prescription.

  1. Hansen K, Mjaatveit MA, Andreassen LV, Mjøs SA, Gudbrandsen OA. Supplementation with a cetoleic acid concentrate decreased the serum LDL-cholesterol concentration in healthy adults with overweight or obesity: a randomised double-blind controlled clinical trial. Br J Nutr, 2026. PubMed
  2. Nundal CH, Tungland SL, Bakke HG, et al. Herring oil rich in long-chain monounsaturated fatty acid (C22:1n-11) lowers plasma lipids and modulates fatty acid composition, oxidation, and inflammation in rats. Front Nutr, 2025. PubMed

This article summarises nutrition science for education. It is not a substitute for individual medical advice; consult a professional before starting a supplement, in pregnancy, or alongside medication.