Zinc Oxide

Annals of Internal Medicine · 2013 · rct · n=903

Daily application of SPF 15+ broad-spectrum sunscreen reduced clinical skin aging by 24% (OR 0.76, 95% CI 0.59–0.98) over 4.5 years compared with discretionary use in the Nambour randomized trial; microtopography confirmed significantly less photoaging progression; Australian NHMRC-funded with no industry involvement

Journal of Cosmetic Dermatology · 2025 · systematic review

Updated review covering 67 articles: tinted sunscreen formulations containing iron oxides achieve visible light attenuation rates exceeding 93%, compared to <10% for non-tinted formulations; confirms iron oxides as the only practical approach to visible light photoprotection in topical sunscreens; recommends tinted sunscreens as standard of care for melasma and PIH-prone patients

Journal of the American Academy of Dermatology · 2015 · rct · n=40

RCT (n=40) over 6 months: tinted sunscreen with iron oxides significantly reduced melasma relapse rate compared to non-tinted sunscreen with equivalent UV protection (p<0.05); both arms had identical UVA/UVB SPF — the only difference was visible light protection from iron oxides; establishes that UV protection alone is insufficient for melasma maintenance

Journal of the American Academy of Dermatology · 1995 · rct · n=46

RCT (n=46) over 24 months: daily sunscreen use produced a significant reduction in solar elastosis on histology versus placebo, while other dermatoheliosis features were largely unchanged; among the earliest biopsy-confirmed evidence that regular sunscreen use limits dermal photodamage.

Journal of Drugs in Dermatology · 2020 · rct · n=24

Study in Fitzpatrick IV-VI skin (n=24): iron oxide-containing tinted sunscreen completely prevented visible light-induced immediate pigment darkening (IPD) and persistent pigment darkening (PPD); untinted mineral SPF 50+ sunscreen (zinc oxide + titanium dioxide) provided no protection against visible light-induced pigmentation — demonstrating that mineral filters alone do NOT block visible light

Photodermatology, Photoimmunology & Photomedicine · 2014 · rct · n=68

RCT (n=68 melasma patients): sunscreen with iron oxides (blocking UV + visible light) combined with 4% hydroquinone achieved significantly greater MASI reduction than UV-only sunscreen + hydroquinone (p<0.01); demonstrates that visible light independently sustains melasma and that iron oxide-containing sunscreens are necessary for optimal depigmenting treatment efficacy