Chlorphenesin

What it is

Chlorphenesin is a synthetic chlorinated glycol ether that was first used as a topical antifungal medicine and later adopted as a cosmetic preservative. It is active against fungi and Gram-positive bacteria and stays effective across a wide pH range, which makes it useful in emulsions and mask essences. It is usually combined with phenoxyethanol or a glycol because it does not cover Gram-negative bacteria well on its own.

What it does well

• Strong antifungal activity at low use levels

  It is particularly effective against yeasts and moulds, the organisms that spoil sheet-mask essences, and remains active in formulas that are too neutral for benzoates or sorbates.

  Moderate evidence

• Allows lower total preservative loads in combination systems

  Because it complements phenoxyethanol's spectrum, the two together can be used at lower individual concentrations than either alone. This is a formulation rationale rather than a proven consumer benefit.

  Limited evidence

Worth knowing

• A documented cause of allergic contact dermatitis, often on the face

  Case reports going back to the 1980s describe facial dermatitis from chlorphenesin in cosmetics, and dermatology journals reported a re-emergence of cases in 2022 and again in 2025. It is not a top-tier allergen, but it is a real one and it is not in most standard patch-test series, so it can be missed.

  Matters most toPeople with unexplained facial dermatitis from skincare, and anyone with known preservative allergy.

• Under-recognised because it is not routinely patch tested

  A 2025 letter in Dermatitis argued chlorphenesin allergy is overlooked precisely because it is absent from many baseline patch-test panels, so real cases go unattributed.

  Matters most toAnyone being investigated for cosmetic contact dermatitis: worth asking for it to be added to testing.

Where the EU stands

Sources (3)

Every link goes to the original: a journal, a PubMed record or an EU document.

1. [1]
   Re-emergence of allergic contact dermatitis from chlorphenesin

   Contact Dermatitis · 2022 · doi:10.1111/cod.14196

   Reports a resurgence of allergic contact dermatitis caused by chlorphenesin in cosmetic products, decades after the first published cases.

2. [2]
   Chlorphenesin-Induced Allergic Contact Dermatitis: An Overlooked Phenomenon?

   Dermatitis · 2025 · doi:10.1089/derm.2024.0433

   A clinical letter arguing that chlorphenesin allergy is probably under-diagnosed because the substance is missing from many routine patch-test series.

3. [3]
   Two cases of facial dermatitis due to chlorphenesin in cosmetics

   Contact Dermatitis · 2005

   Describes facial dermatitis in two patients traced to chlorphenesin used as a preservative in facial cosmetics.