Squalane, a comedogenic ingredient?

The essential points to remember.

Squalane is a stable derivative of squalene, naturally present in human sebum, which imparts excellent biocompatibility and nourishing properties.
Despite its oily texture, squalane is not comedogenic, unlike oxidized squalene.
However, studies investigating the comedogenicity of squalane have been conducted on animal models, which may limit the generalizability of the findings.
The individual tolerance is important in the concept of comedogenicity: an active ingredient may be well tolerated by some and cause comedones in others.

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What do you need to know about squalane?

The squalane is a lipid derived from squalene, a molecule naturally found in human sebum. Squalene contributes to skin hydration and protection, but it is chemically unstable because it contains multiple double bonds that make it susceptible to oxidation. To stabilize it, chemists hydrogenate these double bonds: this yields squalane, a saturated form that is more resistant to air and light. Very stable, the squalane still maintains a chemical structure similar to that of skin squalene and is characterized by an excellent skin tolerance.

Emollient and nourishing, the squalane helps to reinforce the hydrolipidic film and maintain the skin barrier. By reducing transepidermal water loss and improving stratum corneum cohesion, it promotes more supple, better-protected skin against external aggressors. Studies also suggest that squalane may help slow skin aging and enhance the penetration of other active ingredients into the skin, although these effects still require confirmation through further research.

Structures chimiques du squalane et du squalène. — Chemical structures of squalane and squalene.
Source: PubChem.

Squalane: responsible for comedone formation?

The squalane has an oily, nourishing texture, similar to that of plant oils. This richness often leads to questions about its compatibility with oily or acne-prone skin. Yet, squalane does not seem to clog the pores, nor promote comedone formation.

Several studies have shown that squalane is non-comedogenic, unlike squalene, whose unsaturated structure makes it susceptible to oxidation.

Indeed, it is the oxidation products of squalene, known as squalene peroxides, that have a proven comedogenic potential and contribute to the inflammation observed in acne-prone skin. An experimental study specifically compared the comedogenicity of six lipid substances, including squalene and squalane, on the ventral skin of rabbit ears—a model frequently used to assess the comedogenic potential of cosmetic actives. The researchers evaluated both pre- and post-UVA irradiation effects, as well as the lipid peroxidation rate.

The results showed that UVA-irradiated squalene became highly comedogenic, with a significant formation of comedones associated with follicular hyperplasia and hyperkeratosis, whereas squalane, even when exposed to UVA, did not induce any comedonal lesions. Moreover, the lipid peroxidation level was markedly increased for squalene but remained unchanged for squalane, confirming the latter’s chemical stability. This stability explains why squalane is not prone to oxidation and does not generate irritating, comedogenic peroxides. The study therefore demonstrates that only unsaturated lipids, such as squalene or oleic acid, become comedogenic after oxidation, in contrast to saturated lipids like squalane.

Niveaux de peroxydation lipidique sans irradiation par UVA ou après 18h d'irradiation par UVA. — Lipid peroxidation levels without UVA irradiation or after 18 hours of UVA irradiation.
Source: MOTOYOSHI K. Enhanced comedo formation in rabbit ear skin by squalene and oleic acid peroxides. British Journal of Dermatology (1983).

However, this study has certain limitations: it is based on an animal model (rabbit ear), which does not perfectly replicate human skin physiology, even though it remains a reference model in cosmetology for evaluating comedogenicity. Furthermore, comedogenicity is a complex concept to assess, as it depends heavily on each skin type: an active ingredient may be perfectly tolerated by one person and provoke comedones in another. That is why, even though squalane is a priori non-comedogenic, it is recommended to introduce it on its own into your skincare routine. Thus, after several weeks of use, you can observe whether this treatment suits your skin without causing blemishes.