Efficacy and safety of ‘true’ cinnamon (Cinnamomum zeylanicum) as a pharmaceutical agent in diabetes: a systematic review and meta-analysis. Ranasinghe P, Jayawardana R, Galappaththy P, Constantine GR, de Vas Gunawardana N, Katulanda P. Diabet Med. 2012 Dec;29(12):1480-92. doi: 10.1111/j.1464-5491.2012.03718.x