Ethyl Hexanediol
Also known as 2-Ethyl-1,3-hexanediol, Ethylhexylene glycol, EHD, Ethyl hexylene glycol
“CIR Expert Panel says: safe as used in cosmetics.”
Ethyl Hexanediol (2-ethyl-1,3-hexanediol; CAS 94-96-2; C8H18O2) is a C8 branched-chain diol used in cosmetics as a preservative booster and solvent. The CIR Expert Panel reviewed it (JACT 13(6):418-36, 1994, re-confirmed September 2009) and determined it is safe — no conditions or concentration limits were imposed. Genotoxicity studies (Slesinski et al. 1988, PMID 3212782) found no mutagenic or clastogenic activity in Ames, CHO/HGPRT, mouse micronucleus, or rat bone marrow chromosome assays, indicating negligible genotoxic hazard. Repeated cutaneous exposure in rats at up to 4 ml/kg/day for 13 weeks produced no skin irritation, no hematological changes, and no organ-specific toxicity (Van Miller et al. 1995, PMID 7709587). Skin penetration studies (Frantz et al. 1995, PMID 8566473) showed undiluted EHD does not substantially penetrate human skin, supporting a favorable dermal safety profile. The compound is distinct from 1,2-Hexanediol (CAS 6920-22-5, a different structural isomer) and from Octanediol (1,8-octanediol, a different INCI), despite superficially similar names.
Preservative booster: enhances the efficacy of conventional preservatives, allowing lower total preservative loads in cosmetic formulations
Solvent function: useful as a coupling agent in shampoos and liquid cleansers due to dual hydrophilic/lipophilic character
No genotoxicity across multiple assays (Slesinski et al. 1988); low dermal absorption of undiluted material (Frantz et al. 1995)
CIR Expert Panel concluded safe as used in cosmetics with no conditions or concentration limits:418-36, 1994, confirmed 09/09)
- · Historical use as an insect repellent at high concentrations; cosmetic use levels are substantially lower and CIR found no safety concerns
- · Eye contact with undiluted material caused conjunctivitis in animal studies (Ballantyne et al. 1985, PMID 4082459) — not relevant at rinse-off or diluted cosmetic concentrations
- · Poorly water-soluble (4.2% at 20°C); typically used at low concentrations in formulations where solubility is managed by the formulator
CIR Quick Reference Table (12/2017, revised 07/2018) — Ethyl Hexanediol row: Finding=S (Safe), Citation=JACT 13(6):418-36, 1994 confirmed…
“Ethyl Hexanediol | S | | JACT 13(6):418-36, 1994 confirmed 09/09”— QRT-122017revised072018.pdf, p. 49