Xylitol
Also known as Xylite, Birch Sugar, D-Xylitol, Xylit, Pentitol
“CIR Expert Panel says: safe as used in cosmetics.”
Xylitol (CAS 87-99-0; C5H12O5; MW 152.15) is a five-carbon sugar alcohol (pentitol) occurring naturally in many plants including birch, oats, and berries, most commonly produced industrially by hydrogenation of xylose. In cosmetics it functions as a humectant and skin-conditioning agent (up to 14% in rinse-off and 2% in leave-on products per 2019 VCRP data). The CIR Expert Panel assessed xylitol jointly with mannitol and sorbitol in a final report (January 2020, published IJT 2025, PMID 39555956) and concluded these ingredients are safe in cosmetics in the present practices of use and concentration, with no concentration limits or conditions imposed. EU regulatory data (cited in the CIR report) confirms xylitol is not restricted under EU cosmetic product rules. Human studies confirm xylitol suppresses SLS-induced skin irritation and reduces transepidermal water loss at concentrations lower than glycerol (PMID 26370610; PMID 21569743). The well-known canine acute xylitol toxicity (insulin spike at low oral doses) appears nowhere in the CIR cosmetics assessment and is a food-ingestion concern irrelevant to topical cosmetic use.
Effective humectant: attracts and retains moisture in the stratum corneum via five hydroxyl groups
Anti-irritant: inhibits SLS-induced TEWL elevation at lower concentrations than glycerol
Anti-inflammatory: reduces MPO activity and lymphocyte infiltration in irritated skin
Cariostatic activity (inhibits Streptococcus mutans) supports use in oral care cosmetics such as mouthwash and toothpaste
FDA-approved as a direct food additive (21CFR172.395); long, extensive human safety history across food, pharmaceutical, and personal care applications
Not restricted under EU cosmetic product regulations
- · No dermal safety concerns at cosmetic use concentrations; CIR Expert Panel imposed no concentration limits or conditions
- · Oral ingestion at high doses produces osmotic diarrhea — not relevant to topical cosmetic use
- · Canine xylitol toxicity (acute hypoglycemia via insulin release at low oral doses in dogs) is a food/ingestion phenomenon not addressed in cosmetic regulatory frameworks
A phototoxicity study in guinea pigs using 10% xylitol gel/cream showed moderate phototoxic potential, but the CIR Panel concluded this was incorrectly attributed to xylitol (xylitol lacks a UV-absorbing chromophore and cannot directly trigger phototoxicity); two additional negative phototoxicity results with mannitol (same class) supported this conclusion
Safety Assessment of Mannitol, Sorbitol, and Xylitol as Used in Cosmetics (Cherian, Bergfeld, Belsito et al., Int J Toxicol 44(1_suppl):2…
“The CIR Expert Panel concluded that Mannitol, Sorbitol, and Xylitol are safe in cosmetics in the present practices of use and concentration described in this safety assessment.”— Safety Assessment of Mannitol, Sorbitol, and Xylitol as Used in Cosmetics, Final Report, January 24, 2020; published Int J Toxicol 44(1_suppl):22S-43S, 2025; PMID 39555956; Conclusion section