Ethylhexylglycerin

Also known as 2-Ethylhexyl glyceryl ether, 3-[(2-Ethylhexyl)oxy]-1,2-propanediol, Octoxyglycerin, Sensiva SC 50

Ethylhexylglycerin (2-ethylhexyl glyceryl ether; CAS 70445-33-9; C11H24O3) is a synthetic alkyl glyceryl ether used as a preservative booster and skin conditioning agent, typically at 0.3-1.0% in cosmetic formulations. It is commonly co-formulated with phenoxyethanol and other preservatives to enhance antimicrobial efficacy and allow lower preservative concentrations. The CIR Expert Panel issued a final safety assessment in December 2011 (republished as part of 'Safety Assessment of Alkyl Glyceryl Ethers as Used in Cosmetics,' Int J Toxicol 32(3 Suppl):5S-21S, 2013) and concluded that ethylhexylglycerin, chimyl alcohol, batyl alcohol, glyceryl lauryl ether, and isostearyl glyceryl ether are safe as used in cosmetic products. Supporting data included absence of genotoxicity, absence of reproductive/developmental toxicity in oral studies, negative skin irritation and sensitization data in patch tests, and negative phototoxicity/photoallergenicity. However, post-market surveillance has identified ethylhexylglycerin as a documented contact allergen in a small but non-trivial subset of patients presenting to patch-test clinics: Linsen and Goossens (Contact Dermatitis 2016, PMID 26876063) describe it as 'a low-risk, but highly relevant, sensitizer in hypo-allergenic cosmetics,' meaning the prevalence of sensitization in the general population is low but affected individuals often encounter it in products marketed as gentle or fragrance-free, making avoidance difficult. The CIR safety conclusion and the contact allergy literature are not contradictory — the CIR assessment concerns the ingredient's toxicological safety for use, while the dermatitis surveillance tracks individual allergic reactions.