Also listed as PEG on ingredient labels, polyethylene glycol is an ingredient that self-proclaimed “natural” websites 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), but there’s no research indicating that it poses any problem for skin. 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 skin. It is also used internally in medical procedures to flush and cleanse the intestinal tract.