A small amount of in vitro research indicates components in peony root can interrupt the pathway that the skin pigment melanin takes to create cells that lead to dark spots. Although that’s encouraging, the study looked at pure concentrations, not tiny amounts used in cosmetic products. Still, peony root appears to be a potent antioxidant, so it’s not exactly a throwaway ingredient.

One skincare company known for their organic products claims white peony root is “Antibacterial, antifungal and anti-inflammatory used in acne preparations and in toothpastes and other oral hygiene products to promote healthy teeth and gums.”

Sources
Archives of Pharmaceutical Research, April 2001, pages 105–108;
Chemical and Pharmaceutical Bulletin, January 2001, pages 69–72
Biological and Pharmaceutical Bulletin, Volume 35, Issue 12, 2012, pages 198–203
Plant Foods for Human Nutrition, September 2011, pages 275–284
International Journal of Cosmetic Science 2016 Jan 30