Steareth-20 is a synthetic polymer, produced from polyethylene glycol (PEG) and stearyl alcohol.
Steareth 20 is used as cleansing agent, a surfactant and an emulsifier, like many other PEG and other oil derived substances. According to the Cosmetics Database this ingredient is found most often in eye creams, anti-aging skin care products and moisturizers, but has been used to a lesser degree in many other forms of cosmetics.
Steareth 20 is FDA approved for use in cosmetics and further review by the Cosmetic Ingredient Review confirms that Steareth 20 itself is safe for cosmetic use. However, the Cosmetic Database points out that because this ingredient is sourced from PPG it may well contain the contaminants ethylene oxide and 1,4-dioxane, which both have high activity as carcinogens. Although it is highly unlikely that these contaminants would be present in significant concentration, it has been taken into account in the overall safety profile of Stearth 20 which has been labelled as having a low to moderate hazard to health by the Cosmetic Database.
None are recorded.
Source: TruthInAging, https://www.truthinaging.com/ingredients/steareth-20