PEG = polyethylene glycol. There are various forms of PEG. They can serve as surfactants, binding agents, stabilizers and emollients. Common PEG are: PEG 100 for thickening and emulsifying, PEG 7, 80 and 40 for cleansing agents. The greater the number of the PEG, the heavier the molecules. They’re safe to use in cosmetics products.