Squalane

Squalane is a lightweight, colourless oil that closely resembles a lipid the skin already makes. Human sebum contains squalene, spelled with an e, which is one of its natural emollient components. Squalene is unstable and oxidises quickly, so the cosmetic industry converts it into squalane, spelled with an a, by saturating the molecule. That single chemical change turns an ingredient that goes rancid into one that keeps for years.

Production has changed considerably. Squalene was historically obtained from shark liver oil, and that source still exists in some markets, but the overwhelming majority of squalane in modern skincare is plant-derived, usually from olives or from sugarcane fermentation. Sugarcane-derived squalane in particular is valued for its purity and consistency. If the source matters to you, it is generally stated on the packaging, and products will say olive-derived or sugarcane-derived explicitly.

On an ingredients list it appears simply as Squalane. It is used across an unusually wide range of percentages: as a small part of a moisturiser, as a substantial share of a facial oil, or as a single-ingredient product at close to 100%.

Its defining characteristic is how it feels. Squalane is dry-feeling and absorbs quickly for an oil, without the heaviness or residue of richer plant oils. It is also non-comedogenic and contains no fragrance, no known common allergens and nothing that oxidises readily, which makes it one of the safest choices for skin that reacts to most things.

You will meet it in facial oils, moisturisers, cleansing oils, serums and as a carrier for other ingredients, and it appears in products aimed at every skin type from very dry to oily.

Squalane is an emollient and, to a degree, an occlusive. It works physically rather than biologically: it fills the microscopic gaps between cells at the surface, which is what makes skin feel smooth and look even, and it forms a light layer that slows the rate at which water evaporates from the skin. It is not a humectant, so it does not draw water in. It keeps water that is already there from leaving.

That distinction explains how it is best used. Applied to dry skin in a dry room, squalane will make the surface feel soft but has little moisture to hold onto. Applied over a hydrating layer, or onto skin that is still slightly damp, it seals that water in and the effect is considerably better. It is a finishing step rather than a hydrating one.

Because its structure is so similar to a component of the skin’s own oils, it integrates into the surface lipid layer readily and absorbs faster than most oils of comparable richness. This is also why it rarely feels greasy and why it suits oily skin, which is often assumed to need no oil at all. Skin producing excess sebum is frequently short of water rather than oil, and a light, non-comedogenic emollient can help without adding to congestion.

It is chemically stable and unreactive, which is why it is so often used as a carrier for other ingredients: it delivers them without interfering with them or degrading in the bottle.

Squalane is one of the simplest ingredients in skincare to use well, provided you treat it as a sealing step.

• Apply it last among your skincare steps, after serums and moisturiser, and before sunscreen in the morning. Oils go over water-based products, not underneath.
• Use it over hydration, not instead of it. A hyaluronic acid serum or a damp face first, then squalane to hold that water in.
• A few drops is enough. Warm it between the palms and press it into the skin rather than rubbing.
• When: morning and night, as often as you like. No tolerance, no breaks, no sun sensitivity.
• Mix it in if you prefer. A drop or two added to a moisturiser is an easy way to make a light cream richer in winter without buying a second product.
• Pairs well with: everything. It is particularly useful alongside retinoids and exfoliating acids, where it takes the edge off dryness without diluting the active.
• Buffering: applying squalane before a retinoid is a recognised way to make a strong product more comfortable.
• Oily skin can use it. Choose it over heavier plant oils and apply a small amount at night.
• As a cleanser: it works well for dissolving sunscreen and makeup before a second, water-based cleanse.