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

Abstract

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. 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. These results highlight that iron-oxide containing formulas in a foundation format have dual functions and can provide additional benefits in patients' daily routine by masking existing pigmentation and preventing the development of pigmentation triggered by sunlight exposure, extending protection beyond UV spectrum.

Photoprotection for all: Current gaps and opportunities

“…43 In a study comparing a nontinted mineral sunscreen versus tinted products containing iron oxides, the iron-oxideecontaining formulations provided better protection against VL-induced pigmentation in patients with FST IV. 44 Iron oxides may be black, red, or yellow; therefore, these pigments, together with pigmentary TiO 2 , can be mixed in different amounts to create tinted sunscreens to match a range of skin tones. Tinted sunscreens containing iron oxides have been shown to improve melasma lesions and melasma relapses compared to a UV-only sunscreen.…”

Dermatology: how to manage facial hyperpigmentation in skin of colour

“… 29 A study also found that sunscreen with iron oxide improved the appearance of pigmentation compared to mineral SPF 50+ sunscreen and controls in skin phototypes above type II. 30 Thus, VL blocking sunscreens, such as iron oxide-containing formulations, should be included in initial recommendations for all patients seeking care for hyperpigmentation disorders.…”

Iron oxides in novel skin care formulations attenuate blue light for enhanced protection against skin damage

“…The use of sunscreens is central to the treatment of melasma and prevention of hyperpigmentation, 28,29 especially among darkskinned individuals. 13,18,30 Sunscreens containing titanium dioxide (TiO 2 ) and zinc oxide (ZnO) help provide protection against UVA and UVB radiation but provide limited protection against visible and near-infrared radiation, especially at longer wavelengths. 31 Zinc oxide, due to its ability to block a broad spectrum of wavelengths, especially its ability to attenuate wavelengths up through the mid-400 nanometer range, has been shown to play a role in blue light attenuation.…”

“…The use of sunscreens is central to the treatment of melasma and prevention of hyperpigmentation, 28,29 especially among dark‐skinned individuals 13,18,30 . Sunscreens containing titanium dioxide (TiO 2 ) and zinc oxide (ZnO) help provide protection against UVA and UVB radiation but provide limited protection against visible and near‐infrared radiation, especially at longer wavelengths 31 .…”