Preservatives are added to cosmetic products to protect consumers from infections and prevent product deterioration. The concentration of preservatives must be kept as low as possible, and this can be achieved by adding potentiating agents. Ethylhexylglycerin (EHG) potentiates the bactericidal effect of the commonly used 2-phenoxyethanol preservative (1). However, care should be taken not to spread creams containing phenoxyethanol on skin areas in the vicinity of the eyes or eyelids, as phenoxyethanol may cause problems with the tear ducts (2).

Ethylhexylglycerin is a relatively new cosmetic ingredient that is used as a surfactant, emollient and antimicrobial. Since 2002, it has been reported occasionally as a contact allergen (3).

References______________________________________

(1) Langsrud S, Steinhauer K, Lüthje S, Weber K, Goroncy-Bermes P, Holck AL. Ethylhexylglycerin Impairs Membrane Integrity and Enhances the Lethal Effect of Phenoxyethanol. PLoS One. 2016 Oct 26;11(10):e0165228. doi: 10.1371/journal.pone.0165228.

Abstract. Preservatives are added to cosmetics to protect the consumers from infections and prevent product spoilage. The concentration of preservatives should be kept as low as possible and this can be achieved by adding potentiating agents. The aim of the study was to investigate the mechanisms behind potentiation of the bactericidal effect of a commonly used preservative, 2-phenoxyethanol (PE), by the potentiating agent ethylhexylglycerin (EHG). Sub-lethal concentrations of EHG (0.075%) and PE (0.675%) in combination led to rapid killing of E. coli (> 5 log reduction of cfu after 30 min), leakage of cellular constituents, disruption of the energy metabolism, morphological deformities of cells and condensation of DNA. Used alone, EHG disrupted the membrane integrity even at low concentrations. In conclusion, sub-lethal concentrations of EHG potentiate the effect of PE through damage of the cell membrane integrity. Thus, adding EHG to PE in a 1:9 ratio has a similar effect on membrane damage and bacterial viability as doubling the concentration of PE. This study provides insight about the mechanism of action of a strong potentiating agent, EHG, which is commonly used in cosmetics together with PE.

(2) Wang J, Liu Y, Kam WR, Li Y, Sullivan DA. Toxicity of the cosmetic preservatives parabens, phenoxyethanol and chlorphenesin on human meibomian gland epithelial cells. Exp Eye Res. 2020 Jul;196:108057. doi: 10.1016/j.exer.2020.108057.

(3) Aerts O, Verhulst L, Goossens A. Ethylhexylglycerin: a low-risk, but highly relevant, sensitizer in 'hypo-allergenic' cosmetics. Contact Dermatitis. 2016 May;74(5):281-8. doi: 10.1111/cod.12546.

Harries C, Mühlenbein S, Geier J, Pfützner W. Allergic contact dermatitis caused by ethylhexylglycerin in both an ointment and a skin aerosol. Contact Dermatitis. 2016 Mar;74(3):181-2. doi: 10.1111/cod.12471.

Sasseville D, Stanciu M. Allergic contact dermatitis from ethylhexylglycerin in sunscreens. Dermatitis. 2014 Jan-Feb;25(1):42-3. doi: 10.1097/DER.0b013e3182a5d8a9.

Andersen KE. Ethylhexylglycerin-a contact allergen in cosmetic products. Dermatitis. 2012 Nov-Dec;23(6):291. doi: 10.1097/DER.0b013e31827596b1.

Hagen SL, Warshaw E. The Latest Occult "Hypoallergenic" Allergen: Ethylhexylglycerin. Dermatitis. 2017 May/Jun;28(3):220-222. doi: 10.1097/DER.0000000000000249.

Warshaw EM, Buonomo M, Maibach HI, Taylor JS, Zug KA, Atwater AR, Silverberg JI, Belsito DV, Fransway AF, DeKoven JG, Reeder MJ, Sasseville D, Fowler JF Jr, Pratt MD, DeLeo VA. Patch Testing to Ethylhexylglycerin: The North American Contact Dermatitis Group Experience, 2013-2018. Dermatitis. 2021 Sep 27. doi: 10.1097/DER.0000000000000709.

Abstract. Background: Ethylhexylglycerin (EHG) is a recently recognized contact allergen. Objective: The aims of the study were to characterize individuals with positive patch test reactions to EHG and to analyze reaction strength, clinical relevance, and allergen sources.....Conclusions: Ethylhexylglycerin is a rare contact allergen; the positive frequency of 0.25% is similar to other low allergenic preservatives including parabens, benzyl alcohol, and phenoxyethanol. The patch test concentration of 5.0% seems to be nonirritating. Although relatively uncommon, EHG reactions were usually clinically relevant (79.5%), often because of moisturizers/lotions/creams. Copyright © 2021 American Contact Dermatitis Society.