Preservative Biocide A Globally Approved Preservative for Leave-on Applications Phenoxyethanol is a broad spectrum preservative and antimicrobial additive that is highly effective against bacteria, yeast, and fungi. Propylene Phenoxetol works well in a wide pH range (4.0-8.0) making it ideal for water-based cosmetic and personal care products, including baby care, skin care, and hair care products.