Cassia and Ceylon cinnamon differ in safety; Ceylon is lower in coumarin and is generally considered safer for frequent use. Fans will be happy to hear that cinnamon has been studied for its potential effects on blood sugar, inflammation, and overall wellness. Cassia is the most common and affordable variety; it comes from several Cinnamomum species, mainly Cinnamomum cassia, Cinnamomum burmannii (Indonesian cassia), and Cinnamomum loureiroi (Saigon or Vietnamese cassia). Ceylon cinnamon, often called “true cinnamon," comes from the bark of the Cinnamomum verum tree and is less widely available. For anyone using a teaspoon or more per day, Blatner recommends choosing Ceylon cinnamon since it’s lower in coumarin.