Squalane

Squalane is one of the better ingredients in skincare on its own terms. It is close to something human sebum already contains, it sits well on almost every skin type, it does not sensitise, and it has no interesting safety file.

It is on this site for a different reason. It is the clearest case in cosmetics of two entirely unrelated origins sharing one legal name.

Where it comes from, both times

Squalene, with an e, is the unsaturated parent molecule. It was “originally identified in the early 20th century by Tsujimoto in deep-sea shark liver oils”, and the reason sharks were the source is that it makes up “40-80% of the total oil” in the liver. Nothing else concentrates it like that.

Squalane, with an a, is squalene with hydrogen added across the double bonds. That hydrogenation is what makes it stable enough to put in a product; the unsaturated form oxidises.

The shark route works and it is efficient, and the review that documents it also documents the objection: extraction from shark liver oil raises “conservation concerns due to declining shark populations”. Deep-sea sharks are slow to mature and slow to reproduce, which is what makes the fishery a problem rather than merely a preference.

Plant routes now exist and are commercially significant. Olive oil and olive pomace are the established ones, and sugarcane fermentation is the other main source. The molecule that comes out is the same molecule.

The label problem in one line

The INCI name is squalane either way.

Cosmetic ingredients are declared by their established names, and the established name here describes the substance rather than its source. There is no shark squalane and olive squalane in the labelling system, only squalane, exactly as there is no separate name for animal or vegetable Stearic acid.

So for a vegan reader this is a genuine dead end on the back of the pack. Everything else on a cosmetics label that forks by supplier at least tends to fork visibly somewhere. This one does not.

What is left to you: a front-of-pack claim. Plant-derived squalane is more expensive to make, so brands that use it say so, on the bottle or in the product copy. That claim is a marketing statement rather than a regulated term, but its absence is informative in a way absence usually is not, because a brand paying for the olive route has a commercial reason to tell you.

Why it earns its place on skin

Squalane is an emollient rather than an occlusive, which is a distinction worth having.

Petrolatum forms a barrier that stops water leaving. Dimethicone does something similar with a lighter feel. Squalane instead sits within the surface lipids and softens, which is why it reads as weightless and why it is used in products that would feel greasy with anything heavier.

For reactive skin it is close to ideal: no fragrance, no acidity, no active pharmacology, and it does not sensitise. When a routine is being stripped back to find out what is causing trouble, squalane is usually among the things that stay.

Squalene against squalane

If a label says squalene without the a, that is the unsaturated form, and it oxidises. Oxidised squalene has been implicated in comedogenesis, which is the opposite of what most people are buying it for.

The hydrogenated form is the one you want in a bottle, and it is what almost every product uses. The single letter is the whole difference, which makes this one of the few places where a typo on a label would matter.