Xylitol is a five-carbon polyol (sugar alcohol) used in cosmetics primarily as a humectant and skin-conditioning agent. Its multiple hydroxyl groups form hydrogen bonds with water, increasing stratum corneum water content and supporting short- and longer-term moisturization. Clinical investigations show formulations containing xylitol improve corneometric hydration and reduce transepidermal water loss (TEWL), likely via enhanced filaggrin expression and natural moisturizing factor (NMF) generation, translating to better barrier function and cutaneous comfort. In leave-on systems (serums, gels, creams) and rinse-off systems (cleansers), xylitol can be positioned as a plant-sourced, biotechnology-enabled humectant with an excellent safety margin and global regulatory acceptance.

In haircare, xylitol is deployed to hydrate the scalp, mitigate dryness-related tightness, and improve fiber feel by modulating water retention at the hair surface during wet and dry states. In shampoos, conditioners, and scalp tonics, it functions synergistically with other polyols (e.g., glycerol) and carbohydrate-based actives (e.g., xylitylglucoside, anhydroxylitol) to improve rinse aesthetics, reduce squeakiness, and maintain suppleness post-dry. Supplier and trade data further support prebiotic/microbiome-support positioning for scalp-care concepts, while typical cosmetic use levels (≈1–10%) provide flexible dose-response for both high-water and anhydrous stick formats.