The most effective UV filter substance in commercially available sunscreens is zinc oxide. Zinc oxide is a broad-spectrum UV filter, meaning it provides protection against both UVA and UVB radiation. It is considered a physical sunscreen, as opposed to a chemical sunscreen.The mechanism of action of zinc oxide in protecting the skin from harmful UV radiation involves scattering, reflecting, and absorbing the UV rays. When applied to the skin, the zinc oxide particles form a protective barrier that prevents the penetration of UV radiation. The particles reflect and scatter the UV rays, reducing the amount of radiation that reaches the skin. Additionally, zinc oxide can absorb UV radiation and convert it into a less harmful form of energy, such as heat, which is then dissipated.This combination of reflection, scattering, and absorption makes zinc oxide an effective and safe UV filter for sunscreens, providing broad-spectrum protection against the harmful effects of UV radiation on the skin.