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Oxidative Medicine and Cellular Longevity
Volume 2013 (2013), Article ID 702120, 7 pages
Research Article

Examining the Impact of Skin Lighteners In Vitro

1Lonza Consumer Care, 70 Tyler Place, South Plainfield, NJ 07080, USA
2BioInnovation Laboratories, Inc., 7220 W. Jefferson Avenue STE 112, Lakewood, CO 80235, USA

Received 8 February 2013; Accepted 15 March 2013

Academic Editor: Giuseppe Valacchi

Copyright © 2013 James V. Gruber and Robert Holtz. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Three cosmetically important skin lightening agents, hydroquinone (HQ), kojic acid (KA), and niacinamide (NA), consume the bulk of successful skin lightening ingredients in cosmetic applications. However, the mechanisms by which these ingredients work are still unclear. In this study, melanocytes and keratinocytes were treated with high, nontoxic doses of HQ, KA, and NA and the cells were examined by human microarrays and protein assays for several important targets including cytotoxicity, melanin expression, tyrosinase gene (TYR) and protein expression, melanocortin-1 receptor (MC1R) gene and protein expression, cytochrome c oxidase-1 (COX1) gene and protein expression, and ferritin (FTH1) gene and protein expression. It was found that all the skin lighteners examined showed marked increases in TYR, COX1, and FTH1 gene and protein expression, but not in MC1R expression in melanocytes. Upregulation of COX1 and FTH1 genes and proteins was common across both cell lines, melanocytes and keratinocytes. The results of the tyrosinase expression were somewhat unexpected. The role of iron in the expression of melanin is somewhat unexplored, but common and strong upregulation of ferritin protein in both types of cells due to the treatments suggests that iron plays a more pivotal role in melanin synthesis than previously anticipated.