What it is
Polyether-1 is a synthetic polymeric ingredient described in cosmetic ingredient databases as a copolymer of PEG-180, dodoxynol-5, PEG-25 tristyrylphenol, and tetramethoxymethylglycouril monomers. Its role in formulas is viscosity control, meaning it adjusts the thickness and flow of a product so it has the desired consistency and is easier to apply. It appears in products such as sunscreens, conditioners, shave creams, and facial moisturizers.
Safety & warnings
Polyether-1 is used as a texture and consistency modifier rather than as an active ingredient, and it appears at low levels across a range of leave-on and rinse-off products. There is no notable irritation or allergen profile commonly associated with its cosmetic use; people who prefer to avoid PEG-based polymers may wish to check the ingredient list.
Origin & sourcing
It is a fully synthetic material, made by combining (copolymerizing) several monomers, including polyethylene glycol (PEG) segments and a tristyrylphenol-based component, into a single polymer.
Questions everyone asks
What is Polyether-1 used for in sunscreen?
It is a viscosity-controlling agent, helping set the thickness and flow of the formula so it spreads and feels the way the brand intends.
Is Polyether-1 a UV filter?
No. It is a formulation aid that adjusts texture and does not provide sun protection on its own.