PropyleneGlycol (propane-1,2-diol) is the main ingredient in antifreeze and brake fluidand when used in cosmetics for the skin and hair, propylene glycol prevents theescape of moisture. It is a solvent used in cosmetics, hair care products,deodorants and after-shave and can cause moderate skin irritation, redness ofthe skin and dryness. It is considered to be a skin irritant causingdermatitis, especially in children.
PEG is absorbed by the skin so it is better to err on the side of caution and avoid products containing polyethylene glycol (PEG).