Preservatives in Leave‐On Cosmetics Available on the Dutch Market

benzoic acid | chlorphenesin | frequency of use | leave-on cosmetics | phenoxyethanol | potassium sorbate | preservatives | sodium benzoate | sodium metabisulfiteAfter the prohibition of the use of methyldibromoglutaronitrole (and) phenoxyethanol, methylisothiazolinone, and methylchloroisothiazolinone (and) methylisothiazolinone in leave-on cosmetics in the European Union (EU) following the 'epidemics' of allergic contact dermatitis caused by these chemicals, the cosmetics industry had to search for alternatives that are both safe to consumers and effective in protecting the products against microbial contamination and deterioration.We recently found the following rates of sensitisation for preservatives in our 'Additional routine series' among 6886-8892 consecutive patients between 2015 and 2025: sodium metabisulfite 7.4%, iodopropynyl butylcarbamate 3.9%, 2-bromo-2-nitropropane-1,3-diol 1.0%, imidazolidinyl urea 0.8%, diazolidinyl urea 0.7% and phenoxyethanol 0.4% (data on file).To analyse whether this data reflects the current use of preservatives, we have screened the ingredient lists of 350 leave-on cosmetics in the Netherlands for the presence of preservatives allowed in the EU (Table S1). | Materials and MethodsIngredient lists of 350 leave-on cosmetics were collected from www. bol. com, the largest online retailer in the Netherlands.