In a comparison between cinnamon, cardamom, saffron, and ginger supplementation for diabetes control, cinnamon was the only one in this group which improved fasting blood glucose (66).
Cinnamon adverse reactions and interactions:
According to the authors of the meta-analysis by Allen, Robert W et al, none of the 10 trials reviewed reported any significant adverse effects. The authors also reported that animal studies showed liver toxicity, lowering of platelet counts, increase risk of bleeding, and allergic reactions. Potential interactions with cinnamon include medications which affect platelets and anticoagulants. Caution in patients with compromised liver function. (55)