What it is
Laureth-9 is the polyethylene glycol ether of lauryl alcohol carrying an average of about 9 ethylene oxide units, giving it balanced nonionic surfactant behavior. It is used to emulsify oil and water phases and to solubilize lipophilic ingredients within aqueous systems. In sunscreens it contributes to emulsion stability and texture rather than to UV filtering.
Safety & warnings
Laureth-9 (also known as polidocanol) is a common nonionic surfactant generally well tolerated in cosmetic use. As with other ethoxylated surfactants, formulators rely on purification controls to limit ethoxylation by-products.
Origin & sourcing
Synthetic; made by ethoxylating lauryl alcohol, which can be derived from plant oils or petrochemical sources.
Questions everyone asks
Is Laureth-9 the same as polidocanol?
Yes, polidocanol is another name for this ethoxylated lauryl alcohol surfactant.
What role does it play in sunscreen?
It serves as a nonionic emulsifier and solubilizer to stabilize the formula, not as a UV filter.