The cinnamon tree has two varieties: East and West Asiatic. One originates from China and the other from Sri Lanka. The Chinese cinnamon, or cassia, has a punchier flavour so a small quantity can flavour a dish well. The Sri Lankan – true cinnamon, has a softer, fuller and earthier flavour with a distinctly sweeter element to its taste.
I prefer using the true cinnamon as its tastes are more tender and broader. For diabetics there is no difference in the chemistry so both share the ability to help the uptake of insulin. Whilst cassia has a higher level of courmin, only those who take liver medication should be wary of taking this in bulk quantity. And for those who say Chinese cinnamon whether cinnamon sticks or cinnamon powder (ours is top quality) is poisonous, you’d literally have to eat a bucket load to have any detrimental effect.