PEG is an acronym for polyethylene glycol. Various forms of PEG compounds are mixed with fatty acids and fatty alcohols to create a variety of ingredients that have diverse functions in cosmetics, including surfactants, binding agents (which keep ingredients blended), stabilizers, and emollients. Common PEG ingredients include the thickening and emulsifying agent PEG-100 stearate, and many PEG compounds combined with hydrogenated oils, which function as emollients or binding agents. PEG compounds may also function as cleansing agents; for example, PEG-7 glyceryl cocoate, PEG-80 sorbitan laurate, and PEG-40 stearate are mild cleansing agents.
The greater the number following the PEG designation, the “heavier” and more complex the molecule. For example, PEG-200 palm glyceride is a heavier ingredient than PEG-100 stearate. PEG compounds are widely used throughout the cosmetics industry. They’ve been extensively tested and are considered safe for use in cosmetics products.
References for this information:
International Journal of Toxicology, 2006, Supplement 2, pages 121-138
Toxicology, October 2005, issues 1-2, pages 1-38