Determined safe for use in cosmetics with some qualifications, but is suspected to be an environmental toxin; Otherwise there is low risk for allergic reaction or skin irritation (EWG.org).
【Isoceteth-20】
Rating: GOOD
Categories: Cleansing Agent, Emulsifier
Isoceteth-20 is described as a mild non-ionic surfactant, which is noted for its ability to gently cleanse with minimal disruption to skin’s barrier. Manufacturers of this synthetic ingredient also tout its superior foaming properties.
Isoceteth-20 can also be used to solubilize perfumes or other ingredients into water.
The 2012 Cosmetic Ingredient Review assessment of isoceteth-20 concluded that it is safe. Their report surveyed personal care formulations containing up to 21% of this ingredient.
https://www.paulaschoice.com/ingredient-dictionary/ingredient-isoceteth-20.html