Unlike nano-sized particles, which can potentially penetrate the skin barrier and enter the bloodstream, non-nano Zinc Oxide remains on the skin’s surface. This makes it ideal for sensitive skin types and safer for long-term use. Uncoated Zinc Oxide refers to zinc oxide in its natural, untreated form. Unlike coated zinc oxide, which is treated with additional chemicals or compounds to alter its behavior in products (such as making it easier to mix with other ingredients or changing its texture), uncoated zinc oxide remains pure.