Sodium Magnesium Fluorosilicate Middel Absorbent No known benefits Sodium Magnesium Fluorosilicate at a glance Synthetic silicate Absorbent and opacifier Also a thickening agent Known by the trade name LAPONITE-XL 21 XR Sodium Magnesium Fluorosilicate description Sodium magnesium fluorosilicate is an absorbent, opacifier, and thickening agent used in cosmetics. It is a synthetic layered silicate (minerals composed of silicon and oxygen). Sodium magnesium fluorosilicate is also used in dental preparations as a mild abrasive to clean teeth. Sometimes known by the trade name LAPONITE-XL 21 XR, this silicate, according to one of its manufacturers, is designed to improve performance of formulations in the pH range of 5.5 or lower. Use levels of sodium magnesium fluorosilicate in cosmetics are 0.1–5%, depending on formulary needs and/or desired aesthetics. When used above 2% in water, sodium magnesium fluorosilicate forms thixotropic (quick breaking) gels that leave a smooth skin feel. Related ingredients: Lithium Magnesium Sodium Silicate