Oleth-10

Oleth-10 is an ethoxylated oleyl alcohol surfactant/solubilizer used at low-to-moderate levels to emulsify and help cleanse or disperse oils. As a nonionic surfactant, it can still disrupt the stratum corneum lipids and increase permeability, and patch-test/clinical experience shows surfactants are a common trigger for stinging and eczema flares, especially in leave-on products or compromised skin. Given its barrier-disruptive potential and higher risk in sensitive/atopic populations, I score it as moderate irritancy. Safety Notes: Oleth-10 (PEG-10 oleyl ether) is most often used as a nonionic surfactant/solubilizer and emulsifier aid; in many leave-on serums, toners, and sprays it appears at low levels (~0.1–1%) to solubilize fragrance/oils or improve clarity and wetting. In rinse-off cleansers, micellar waters, and especially oil cleansers/makeup removers and self-emulsifying cleansing oils available OTC, it can be used at much higher levels (commonly 3–10%, with observed high-strength systems up to ~15%) to drive rapid self-emulsification and cleansing performance. This range reflects real-world commercial usage rather than typical “recommended” levels, and higher values are more typical of rinse-off or cleansing formats than leave-on products.