INCI: benzyl alcohol, benzoic acid, dehydroacetic acid and tocopherol
Euxyl® K903 is the latest "natural conform" preservative from Schülke. This is a very effective preservative at low concentrations for all rinse-off and leave-on products.
Just like all other weak organic acids, its efficacy is extremely pH dependant and optimum application pH is pH<6. (we recommend 5.0-5.5)
In the EU there is a limitation for benzoic acid and benzyl alcohol concentration and the max. allowed concentration for Euxyl K903 is 1,23%. Keep that in mind if you're applying other ingredients that are preserved with benzyl alcohol or benzoic acid.
Since the preservative has lipophilic components, it is not completely water soluble. In products without an oil phase (lotions) or a surfactant (shampoo, facial cleansing foam) you'll need a solubilizer to incorporate it into water. Technically it is possible to use a solubilizer like natural solubilizer clear plus
for this purpose. We recommend however to use this preservative only in lipid containing formulations (lotions, balms) to avoid sensitization.
Read our blog post
about benzyl alcohol and how to work with it for a best performance and least sensitization.