Talc

Talc is an inert mineral filler/absorbent used at high levels in powders and some creams, and it is generally non-reactive on intact skin with a low rate of positive patch tests. However, in eczema-prone or compromised skin it can cause mild irritation via dryness and friction/occlusion effects (and mechanical irritation in skin folds), so I cannot score it as fully inert for high-sensitivity populations. Safety Notes: In consumer skincare and cosmetic-adjacent skincare (e.g., body lotions/creams, facial moisturizers, cleansers), talc is commonly used at low levels (~0.1–5%) as an absorbent, slip agent, and opacifier, with some products using ~5–15% for a drier, powdery skin feel. The highest OTC levels are seen in loose/pressed body powders and some dry mask/powder cleanser formats where talc can be the dominant base (often 50–90%+), with extreme cases approaching ~95% when combined with minor fragrance/binders and other powders; these are leave-on powders rather than rinse-off products.