Nylon-12

Nylon-12 is an inert synthetic polymer powder used in cosmetics (often a few percent) for slip, oil absorption, and blurring, and it is generally non-reactive in standard patch-testing with very low rates of irritation. The main risk is mechanical/drying discomfort or occlusion-related exacerbation in highly compromised eczema skin rather than true chemical irritation or sensitization. Given its strong tolerability profile but acknowledging rare reactivity in severely barrier-impaired patients, it fits "exceptionally gentle" rather than completely inert. Safety Notes: Nylon-12 is used as a texturizing/soft-focus polymer powder and slip agent; in many leave-on skincare (lotions/serums/primers) it appears at low levels (~0.1–2%) to improve feel and reduce tack without visible powderiness. In oil-control and blurring products (primers, matte moisturizers, silicone gel creams, sunscreen primers) and some loose/pressed hybrid skincare-makeup items available OTC, total nylon-12 loading commonly rises to ~5–15% and can reach ~20–25% in very high-powder, strong-mattifying consumer formulas. Rinse-off use exists (e.g., cleansers) but typically stays low due to cost/need, while the highest levels are overwhelmingly in leave-on, powder-rich textures.