Natural Illite Liquid Mineral Extract: A Clinical Study of an Emulsion to Improve Skin Barrier Function

In this study, we evaluated the skin barrier improvement effect of a natural liquid mineral extract of mica clay, commonly used in cosmetics. The mica particles have an average size of approximately 4.77 μm, with a range around 10 μm. The specific surface area is about 8.8 m2/g, the average pore volume is 0.02 cm3/g, and the pore size is 10.82 nm. The extraction process involved mixing the mineral materials with distilled water for 2 days. The final extraction solution contained approximately 6 mg/L of potassium, as determined using inductively coupled plasma optical emission spectrometry (ICP-OES). A cosmetic emulsion containing the natural illite liquid mineral extract was assessed for stability in pH, viscosity, color, and odor under various conditions, including 4 °C, 25 °C, 45 °C, temperature cycling, and daylight, over 3 months. A placebo-controlled clinical trial was conducted to evaluate the skin barrier improvement and soothing effects on skin damaged by sodium lauryl sulfate (SLS) exposure or tape stripping. The test product demonstrated a statistically significant improvement in transepidermal water loss (TEWL) and skin redness compared to the control product. Therefore, the natural illite liquid mineral extract appears to enhance skin barrier function and soothe damaged skin, suggesting its potential therapeutic benefits.