Cinnamon extract and cinnamon bark can have antimicrobial and antioxidant properties, but it can also be a skin irritant. The powder is often used in DIY face masks for acne-prone and/or oily skin.
Cutaneous and Ocular Toxicology, March 2007, pages 227–233
Letters in Applied Microbiology, January 2002, pages 27–31
Contact Dermatitis, October 1993, pages 202–205