PEG-100 Stearate is made by combining natural oils (oftentimes palm or coconut) with Stearic Acid to form a water-soluble ester. It can also be a synthetic polymer made by combining Oxirane (Ethylene Oxide) and fatty acids (source). PEG-100 Stearate is primarily used by the cosmetics and beauty care industry as an emollient, an emulsifier and a moisturizer, although PEG Stearates in general are also known to clean the skin and hair by helping water to mix with oil and dirt so that they can be rinsed away, according to CosmeticsInfo.org.