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 PhDa, Pearl E Grimes MDb, Stephen Lynch PhDa,b, Kalli Ji PhDa, Manisha Brahmachary PhDa, Qian Zheng Md PhDa, Charbel Bouez PhDa, 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