Glucose
Also known as Glucose, D-Glucose, Dextrose, Grape sugar, Blood sugar, D-glucopyranose
“CIR Expert Panel says: safe as used in cosmetics.”
Glucose (CAS 50-99-7) is a monosaccharide and primary cellular energy source, used in cosmetics as a humectant and skin conditioning agent. The CIR Expert Panel's 2014 group safety assessment (published IJT 38(1_suppl):5S-38S, 2019; PMID 31170840) explicitly named glucose as one of the 25 monosaccharides and disaccharides assessed, concluding they are 'safe in the present practices of use and concentration.' Glucose is a GRAS direct food additive (21 CFR 184.1857, D-glucose) meeting Food Chemical Codex specifications, and is listed in REACH Annex IV (exempt from registration). The CIR FR noted 425 VCRP-reported cosmetic uses for glucose (third highest in the group after sucrose and trehalose), with the highest reported leave-on use concentration of 91% in non-coloring hair preparations and 97.8% in ingestible oral hygiene products. Glucose is listed in REACH Annex IV alongside fructose, galactose, lactose, sodium gluconate, and sucrose. Kum et al. (Int J Mol Sci 2020; PMID 32138354) demonstrated that glucose significantly reduced melanin content in alpha-MSH-stimulated melanocytes without cytotoxicity, and showed whitening efficacy in a pigmented 3D human skin equivalent — confirming biological activity in skin with no adverse effects at tested concentrations.
Humectant: attracts and retains water through multiple hydroxyl groups; 425 reported VCRP cosmetic uses — third highest of all 25 saccharide ingredients in the 2014 CIR assessment.
Skin conditioning: most commonly reported cosmetic function; used at concentrations up to 91% in leave-on non-coloring hair preparations and 97.8% in ingestible oral hygiene products.
GRAS direct food additive (21 CFR 184.1857) and REACH Annex IV listed — regulatory track record spanning food, pharmaceutical, and cosmetic use.
Anti-melanogenic effect without cytotoxicity: glucose significantly reduced melanin content in alpha-MSH-stimulated melanocytes and demonstrated whitening efficacy in a pigmented 3D human skin equivalent model (Kum et al. 2020, PMID 32138354).
Endogenous metabolite: glucose is the primary cellular energy substrate, rapidly metabolized via glycolysis and the citric acid cycle; dermal absorption from cosmetic use poses minimal systemic risk.
Group (class-level) safety assessment: glucose was included as one of 25 saccharide ingredients. Individual CIR report does not exist as of the QRT date (2018); evidence basis is robust for the class.
Glucose is an energy substrate for skin microbiota; very high concentrations in leave-on products (up to 91%) are reported, but the CIR Panel found this acceptable given the oral and dermal safety profile and GRAS status.
The CIR FR noted glucose permeation through skin in vitro (permeability coefficient 9.5 x 10^-5 cm/h through full-thickness mouse skin; 0.29 cm/h through dermis alone) and in vivo in Rhesus monkey (mean permeability rate 4.41 x 10^-6 cm/sec for 20% glucose applied topically), but systemic exposure from cosmetic use was not considered a safety concern given the GRAS food status and endogenous glucose metabolism.
CIR Quick Reference Table (12/2017, revised 07/2018) — Glucose row: Finding=S (Safe), Citation='Final report 03/2014 available from CIR'
“Glucose | S | | Final report 03/2014 available from CIR”— QRT-122017revised072018.pdf, p. 51