Creative Touch Permanent Makeup and Aesthetics

Squalene is a 30-carbon polyunsaturated triterpene lipid – distinct from fatty acids in its biosynthetic origin and molecular structure – produced endogenously via the mevalonate pathway in the liver and sebaceous glands, and a precursor to cholesterol and steroid hormone synthesis. In human sebum it constitutes approximately 12% of total lipid content, making it one of the most abundant sebum components and one of the most distinctively human: most mammalian species produce negligible amounts of squalene in sebum, whilst humans secrete it at concentrations high enough to make it a measurable functional component of the surface lipid film. Plant-derived squalene, used in cosmetic formulations, is sourced predominantly from olive oil and, increasingly, from sugarcane fermentation as an alternative to the historically used shark liver oil. ^[1]

Antioxidant Function and Oxidative Liability

Squalene’s primary functional role at the skin surface is antioxidant – it quenches reactive oxygen species generated by UV irradiation, protecting underlying lipids, proteins, and cellular structures from oxidative damage. It is the first line of sacrificial antioxidant defence in sebum, oxidising preferentially before more structurally critical lipids are damaged. This protective role is genuine and well-characterised.

The complication is that squalene’s antioxidant function comes at a cost. Under sustained or intense UV exposure, squalene is converted to squalene monohydroperoxide and subsequently to squalene peroxide – highly comedogenic oxidation products that promote follicular hyperkeratinisation, increase sebum viscosity, and contribute to the microcomedone formation that initiates acne vulgaris. Peroxidated squalene has been detected in higher concentrations in the sebum of acne-prone individuals compared to non-acne controls, and its comedogenic activity has been demonstrated in rabbit ear assays. The same molecule that protects skin under moderate UV stress becomes a pathological driver under excessive oxidative load – a dose and context dependency worth holding precisely rather than characterising squalene as simply beneficial or harmful. ^[1]

Squalane in Topical Formulations

Squalene is chemically unstable, its six double bonds make it highly susceptible to oxidation, limiting its shelf life in topical formulations. Squalane, the fully hydrogenated and saturated derivative, resolves this instability: the hydrogenation process eliminates all six double bonds, producing a molecule with no sites available for oxidative attack. Squalane retains squalene’s emollient and skin-compatible properties whilst offering the oxidative stability of a saturated fat alongside a lightweight, non-comedogenic skin feel. For clients with acne-prone or UV-exposed skin for whom high-PUFA oils carry oxidation liability, squalane-based formulations offer a well-reasoned stable alternative.