Magnesium Aluminum Silicate

Magnesium aluminum silicate is an inert clay/mineral used primarily as a thickener, suspending agent, and opacifier, typically at low percentages in leave-on and rinse-off products. It has a very low rate of irritation in clinical use and patch testing, with most issues being rare mechanical dryness/tightness in highly compromised barriers rather than true chemical irritancy. Given its broad tolerability but acknowledging occasional reactivity in severely sensitive or eczema-prone skin, it fits best as exceptionally gentle rather than completely inert. Safety Notes: Magnesium aluminum silicate (a smectite-type clay/thickener) is used at very low levels (~0.05–0.3%) in emulsions and liquid cleansers as a suspending/viscosity aid, and more commonly around ~0.5–3% in lotions, creams, and masks for rheology and texture. The upper end is observed in consumer clay-based face masks, mud packs, and some mineral/powder or paste-style products where total clay structuring can reach ~10–15% while remaining OTC; leave-on masks/pastes tend to run higher than rinse-off cleansers due to desired body and oil-absorption.