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

July 2020 | Volume 19 | Issue 7 | Original Article | 712 | Copyright © July 2020

Published online June 18, 2020

Hawasatu Dumbuya PhD,a Pearl E. Grimes MD,b Stephen Lynch PhD,a Kaili Ji PhD,a Manisha Brahmachary PhD,a Qian Zheng MD PhD,a Charbel Bouez PhD,a Janet Wangari-Talbot PhDa

aL’Oréal Research and Innovation, Clark, NJ bVitiligo & Pigmentation Institute, Los Angeles, CA

fixed effects, and subject as random effect. P-values <0.05 were considered statistically significant.

For visible light protection factor (VL-PF), the slope from baseline to day 4 of estimated ITA° change from baseline was calculated, and the ratio between the mean slope for the VL-irritated bare skin over the mean slope of the VL-irritated skin treated with one of the products was obtained as the VL-PF. All calculations were performed using SAS ver 9.0.


Clinical assessment for skin pigmentation, including statistical comparisons to baseline values, for each treatment from day 0 to day 14, are illustrated in Figure 2A. The untreated zone and the zone pre-treated with Product A showed a perceivable and statistically significant increase in pigmentation from day 0 to day 3, which was persistent to up to day 14. Pre-treatment with Products B and C demonstrated a statistically significant but less-pronounced increase in pigmentation, which was maintained at minimal level following the series of four consecutive exposures to visible light* and until day 14, as shown in Figure 2B.

The mean values of ΔL* are shown in Figure 3A. In alignment with clinical assessment for skin pigmentation, untreated zone and Product A presented a statistically significant decrease in