What is “Pullulan” and what is it used for?

Pullulan is a naturally derived polysaccharide obtained by fermenting sugars, such as glucose, sucrose or starch, using the micro-organism Aureobasidium pullulans. During this biotechnological process, the sugars are converted into long chains of repeating molecules, giving rise to a water-soluble, neutral and biodegradable polymer. Its production therefore relies on a controlled fermentation pathway, comparable to that used for certain other cosmetic ingredients, such as hyaluronic acid.

Structurally, pullulan is composed of maltotriose units, each corresponding to three glucose molecules linked together, themselves connected by specific α-(1→6) glycosidic bonds. This organisation confers a flexible linear structure, distinct from that of many other, more highly branched polysaccharides. This particular feature notably explains its ability to form homogeneous, transparent films in aqueous solution, while maintaining good affinity with water. Pullulan is thus distinguished by physicochemical properties that are advantageous for cosmetic use: it is non-ionic, stable over a wide pH range, and compatible with many other ingredients, which facilitates its incorporation into different formulations.

Pullulan is primarily used in cosmetics for its film-forming and texturising properties. Water-soluble and non-ionic, it forms a thin, homogeneous and transparent film on the surface of the skin and hair, perceptible through an immediate tightening effect. This film acts as a physical barrier, limiting transepidermal water loss and thereby helping to maintain skin hydration. In formulations, it also plays a structuring role: it improves viscosity, stabilises emulsions and promotes cohesion between the different ingredients, including in the presence of surfactants. This versatility explains its incorporation into numerous products (serums, masks, hair care), where it also contributes to a surface-smoothing and softening effect.

On the skin, this capacity to form a film gives pullulan an immediate smoothing and tightening effect, which is purely physical. It does not act in depth, but improves the appearance of the epidermis by evening out its surface and temporarily reducing the visibility of irregularities. In addition, this film can facilitate the gradual diffusion of certain active ingredients by limiting their evaporation and maintaining a hydrated environment that is favourable to their activity. On the hair, pullulan is deposited along the hair fibre, where it helps to coat the cuticle, improve softness to the touch and enhance shine, without weighing the hair down.

Beyond these surface effects, some studies suggest a potential role for pullulan in the process of wound healing.

An experimental study conducted in rats assessed the topical application of a pullulan gel on cutaneous wounds. The results show a significant improvement in several biological markers involved in healing: an increase in collagen, protein and DNA content, as well as an acceleration of wound contraction. The time to epithelialisation was reduced by half, and histological analyses demonstrated better dermal regeneration, neovascularisation and increased collagen synthesis. Although these findings come from an animal model, they suggest that pullulan could help support skin repair.

In addition, photoprotective properties have also been investigated using exopolymers derived from Aureobasidium pullulans. In a murine model exposed to UVB for 15 weeks, the topical application of these polymers helped to limit oxidative stress induced by UV radiation, notably by reducing the production of free radicals, preserving glutathione stores, an endogenous antioxidant, and inhibiting the activation of metalloproteinases, enzymes involved in collagen degradation. A decrease in pro-inflammatory cytokines and in keratinocyte apoptosis was also observed. These findings suggest a protective potential against photoageing, although clinical data in humans remain limited to date.

Finally, beyond its conventional use, pullulan is attracting growing interest for more advanced applications, particularly in the development of active ingredient delivery systems. Its ability to form solid, biocompatible structures is exploited in the manufacturing of dissolvable microneedles, used in dermatology to enhance the penetration of certain compounds. Although these technologies are still mainly explored in a medical context, they illustrate the potential of pullulan as a carrier, with possible transposition into cosmetics.

Pullulan is regarded as a very well‑tolerated ingredient for topical use. To date, the scientific literature has not reported any significant adverse effects associated with its use in cosmetic products. Its lack of particular chemical reactivity greatly limits the risk of skin irritation or sensitisation. Furthermore, it does not penetrate deeply into the skin and acts mainly at the surface, which further reduces the likelihood of undesirable reactions. It should also be noted that, based on current knowledge, pullulan does not present any specific contraindications: it may be used in children, pregnant or breastfeeding women, as well as in individuals with sensitive skin or those prone to skin disorders.

That said, as with any ingredient, tolerance may vary from one individual to another, which is why it is advisable to perform a patch test when using a new cosmetic product for the first time.

• KANG S. J. & al. Inhibition of UVB-induced skin damage by exopolymers from Aureobasidium pullulans SM-2001 in hairless mice. Basic & Clinical Pharmacology & Toxicology (2015).

• MORGANTI P. & al. Pullulan for advanced sustainable body- and skin-contact applications. Journal of Functional Biomaterials (2020).

• DONNELLY R. F. & al. Pullulan-based dissolving microneedle arrays for enhanced transdermal delivery of small and large biomolecules. International Journal of Biological Macromolecules (2020).

• LONCHIN S. & al. Topical administration of pullulan gel accelerates skin tissue regeneration by enhancing collagen synthesis and wound contraction in rats. International Journal of Biological Macromolecules (2020).

• KENNEDY J. F. & al. Pullulan in pharmaceutical and cosmeceutical formulations: A review. International Journal of Biological Macromolecules (2023).