Ethylhexylglycerin

What it is

Ethylhexylglycerin is not a preservative in the narrow sense but a booster. It makes the cell envelope of micro-organisms more permeable and thereby increases the effect of the actual preservative, usually phenoxyethanol. This allows the amount of the classic preservative to be reduced without losing shelf life. In addition the substance has a skin-conditioning and odour-inhibiting effect.

The most remarkable point follows from that role. In a Belgian review of thirteen allergy cases over 25 years, the culprit products were predominantly cosmetics that stay on the skin — among them a striking number of creams, sun protection products and deodorants advertised as “hypoallergenic” or “free from preservatives”. The substance is a rare but clinically relevant contact allergen, and it sits by preference exactly where one expects it least.

Why

• Why the classification reads “low risk”: the largest evaluation to date comes from the North American Contact Dermatitis Group. Of 15,560 people tested, 39 reacted allergically, that is 0.25 per cent. This frequency is in the same range as for parabens, benzyl alcohol and phenoxyethanol.
• Rare does not mean without consequence. In the same evaluation the reaction was actually the cause of the current eczema in almost 80 per cent of those affected. Anyone who is allergic will notice it — but will hardly find the trigger without targeted testing, because the substance is not perceived as a preservative.
• The mechanism explains why less can be more: the substance damages the membrane of micro-organisms and makes them vulnerable to phenoxyethanol. The formulation therefore manages with less preservative. That is an advantage, not a trick.
• “Free from preservatives” is therefore a particularly misleading claim in this case. Preservation still takes place, only with a different combination. The question is not whether a product is preserved but with what — and whether that is tolerated by the person concerned.
• In the salon products of this lexicon the substance appears mainly in rinse-off formulations. The documented allergy cases, by contrast, involved almost exclusively products that stay on the skin. This distinction matters for the assessment and is carried along here explicitly.

When the assessment differs

• Known contact allergy to ethylhexylglycerin: then the product is unsuitable, regardless of the classification above. This can only be established by a patch test.
• Face, neck and armpits: the sites most frequently affected in the case series. For the salon that mainly means hairline and nape.
• Existing eczema or atopic dermatitis: on pre-damaged skin the threshold for sensitisation is lower.
• Use that stays on the skin: creams, sun protection and deodorants were the documented triggers. The transfer to rinse-off shampoos does not apply unexamined.
• Occupational contact: anyone working daily with many products has a higher total exposure on the hands. That applies to this substance as it does to surfactants.

Open questions

• Concentration in the specific product: not available. The substance is usually used in small amounts; how small is stated nowhere.
• Frequency in rinse-off hair products: not investigated separately. The available figures come from patch test series in which cosmetics that stay on the skin were to the fore.
• Transferability of the North American figures to Europe: not checked. Test series at dermatology clinics also reflect a pre-selected group, not the general population.
• Interaction with the actual preservative: the substance increases its effect on micro-organisms. Whether it thereby also increases its effect on the skin is not backed by data here.
• Regulatory status: not checked; statements on use and maximum levels are not quoted second-hand.

Sources for this assessment

• Warshaw E. M. u. a.: Patch Testing to Ethylhexylglycerin — The North American Contact Dermatitis Group Experience, 2013–2018. Dermatitis, 2022. Begutachtete Fachzeitschrift, abgerufen am 10.09.2026.
• Aerts O. u. a.: Ethylhexylglycerin — a low-risk, but highly relevant, sensitizer in hypo-allergenic cosmetics. Contact Dermatitis, 2016. Begutachtete Fachzeitschrift, abgerufen am 10.09.2026.

Related substances

Applies to: Preservation and solvents

• Alcohol Denat. — Preservative, solubiliser
• Benzoic Acid — Preservative
• Benzyl Alcohol — Preservative, fragrance component
• Phenoxyethanol — Preservative

Further substances from the same group for which a long-form assessment already exists.