Impact of Iron-Oxide Containing Formulations Against Visible Light-Induced Skin Pigmentation in Skin of Color Individuals

Hawasatu Dumbuya PhD, Pearl E Grimes MD, Stephen Lynch PhD, Kalli Ji PhD, Manisha Brahmachary PhD, Qian Zheng Md PhD, Charbel Bouez PhD, Janet Wangari-Talbot PhD

Visible light (400–700nm), which contributes to 45% of solar radiation, contributes to skin darkening and worsening of dyschromias, particularly in individuals with Fitzpatrick skin phototypes III and higher.

The pathogenesis of melasma is incompletely understood, which poses a challenge for disease management. Causative factors include genetics, ultraviolet (UV) radiation, cosmetics, pregnancy, hormonal therapy, phototoxic drugs, and various medications.

Currently, sunscreens provide limited protection against that spectrum. Due to their capabilities in absorbing, scattering, and reflecting visible light, topical products containing pigments and/or metal oxides can provide additional photoprotection.

In this study, the efficacy of two formulations containing iron oxide was evaluated in preventing visible light-induced pigmentation compared with a non-tinted mineral SPF 50+ sunscreen. Expert grading and colorimetry demonstrated that the iron-oxide containing formulations significantly protected against visible light-induced pigmentation compared to untreated skin or mineral SPF 50+ sunscreen in Fitzpatrick IV individuals.