Also listed as PEG on ingredient labels, polyethylene glycol is an ingredient that self-proclaimed “natural” Web sites have attempted to make notoriously evil. They gain a great deal of attention by attributing horror stories to PEG, associating it with antifreeze (however, antifreeze is ethylene glycol, not polyethylene glycol), and there is no research indicating that PEG compounds pose any problem for skin. Quite the contrary: PEGs have no known skin toxicity and can be used on skin with great results (Sources: Advanced Drug Delivery Reviews, June 2002, pages 587–606; and Cancer Research, June 2002, pages 3138–3143). The only negative research for this ingredient indicates that large quantities given orally to rats can cause tumors, but that is unrelated to topical application.
Polyethylene when it is not combined with glycol, is the most common form of plastic used in the world. It is flexible and has a smooth, waxy feel. When ground up, the small particles are included in scrubs as a gentle abrasive. When mixed with glycol, it becomes a viscous liquid. In the minuscule amounts used in cosmetics, it helps keep products stable and performs functions similar to those of glycerin. Because polyethylene glycol can penetrate skin, it is also a vehicle that helps deliver other ingredients deeper into the skin. It is also used internally in medical procedures to flush and clean the intestinal tract.