Omega-11.

Cetoleic acid, the 22-carbon n-11 monounsaturate, is a natural constituent of herring, capelin and other pelagic fish oils that also carry EPA and DHA. Any oil supplying meaningful n-11 content supplies omega-3 with it. Separating their contributions in a whole-oil product is not possible from a label. That co-occurrence is the single most important context for reading any n-11 claim.

The suggestion from feeding studies is that 22:1n-11 rich oils raise EPA levels beyond what their own EPA content would explain, pointing at an effect on the elongation and desaturation pathway. The work is largely in animals and in cell systems. It is a plausible and interesting mechanism, not a settled one, and the size of any effect in people is unknown. Read it as mechanistic rather than clinical.

Astaxanthin spans the lipid bilayer and quenches radicals at both the surface and the interior, which complements tocopherol activity. Marine oil products often carry it both as a stability aid and as an active. It also needs a lipid vehicle for absorption, which the oil supplies. The pairing works in both directions.

Fat absorption depends on emulsification and micelle formation, and phospholipids assist both steps ahead of bile. Lecithin is used in softgel and emulsion formats for that reason. The gain is largest in people with reduced bile output or when the oil is taken without a meal. Taking any marine oil with food achieves much of the same thing.

Phospholipid-bound fatty acids follow a partly different absorption route from triglyceride-bound ones and appear to need less bile. Combining a phospholipid source with a triglyceride marine oil covers both routes. Krill also carries its own astaxanthin. The n-11 content of krill differs from that of pelagic fish oils, so the two are not interchangeable on that specific fraction.

Medium-chain fatty acids pass into the portal circulation directly, whereas long-chain fatty acids are packaged into chylomicrons via the lymphatics. Blending them changes the overall absorption profile of a product without either one blocking the other. MCT is often used as a carrier oil for that reason. It also dilutes the long-chain content per serving, which matters when reading a label.

Gamma and delta tocopherols are more effective than alpha at inhibiting peroxidation in bulk oil, which is why food-grade stabilisation blends favour them. Marine oils with mixed tocopherols usually hold lower peroxide values through shelf life. The distinction matters for oil quality rather than for the person's vitamin E status. Check the peroxide value on the certificate of analysis if the maker publishes one.

Tocopherol becomes a radical itself once it has donated its hydrogen, and ascorbate at the aqueous interface reduces it back to the active form. This recycling loop is textbook antioxidant biochemistry. It is why vitamin C and vitamin E are described as a pair in lipid protection. It applies inside the body, not to the oil in the bottle.