Polyethylene

Polyethylene is an inert synthetic polymer used mainly as a film-former, viscosity modifier, or microplastic exfoliant; it is not chemically reactive and is generally non-sensitizing at typical leave-on or rinse-off use levels. However, in real-world eczema and barrier-impaired patients, particulate polyethylene (when used as beads) can contribute to mechanical irritation/friction and worsen microfissuring, so I do not score it as fully inert for sensitive-skin safety. Safety Notes: In consumer skincare, polyethylene is most often used as a solid particulate (microbead/powder) for slip and abrasion in exfoliating cleansers and scrubs, where it can appear at very low levels (~0.05–0.5%) in mild “polishing” products. The highest OTC concentrations are seen in heavy-duty face/body scrubs and pumice-style exfoliating creams, where polyethylene can comprise a substantial portion of the formula (commonly 5–15% and observed up to ~25%) to deliver strong mechanical exfoliation; these are typically rinse-off products. Use has been reduced or restricted in many markets for rinse-off microbeads due to microplastics regulations, but polyethylene still appears in some products (including as a texturizing polymer/wax) where permitted.