Zinc oxide

Zinc oxide is an inorganic filter that both absorbs and scatters UV. Unlike most organic filters it covers long-wave UVA1 on its own, which is why it anchors so many "broad spectrum" mineral formulas[2].

Safety

It is one of only two filters the FDA currently considers generally recognised as safe and effective[1]. The nano question has been studied intensively; penetration through intact skin is negligible[2][3]. The EU restricts it from sprayable products to avoid inhalation, not because of skin concerns[3].

Trade-offs

White cast and a dry, matte feel. Tinted formulas and blends with titanium dioxideTitanium dioxideStrongTitanium Dioxide · Inorganic UV filterStrong UVB and short-UVA mineral filter; extensively reviewed for nano safety.Open in the Index → manage both. Layer ascorbic acidAscorbic acidStrongAscorbic Acid · Vitamin C (L-ascorbic acid)The active form of vitamin C; well-evidenced for photoageing at 10–20 % and low pH, but unstable.Open in the Index → underneath for additional antioxidant protection.