Table 5.

Summary of clinical trials showing the effects of cinnamon on insulin resistance and T2DM.

Year	Extract/oil	Type of cinnamon	Part	Dosage	Model	Follow-up duration	Result
2010 81	Powder	Cinnamomum cassia	Bark	2 g/d	Human	12 weeks	Reduction in HbA1C and FPG
2007 82	Capsule	C cassia		1 g/d	Human	3 months	No significant effect on insulin levels, A1C, or fasting glucose
2009 83	Capsule	C cassia		1 g/d	Human	90 days	Reduction in HbA1C
2018 84	Powder filled in a capsule	Cinnamomum verum	Bark	1 g/d	Human	3 months	Improvement in FPG, HbA1C, insulin resistance, fasting insulin, and 2 hpp
2018 85	Extract	C verum	Cinnamon stick	3 g/d	Human	90 days	-
2014 86	Sticks	C verum	Inner bark		Human	8 weeks	Reduction in fasting blood sugar (FBS)
2020 87	Extract encapsulated in a capsule	Cinnamomum zeylanicum	Bark	225 mg/d	Human	12 weeks	Reduction in FBS, HbA1C, and insulin resistance
2016 88	Capsule	C verum	Bark	1 g/d	Human	12 weeks	Reduction in FBS and HbA1C
2015 89	Alcohol extract	C zeylanicum		50 mg/kg to 200 mg/kg body weight	Rats	4 weeks	Reduction in glucose level
2015 90	Aqueous extract	C cassia	Bark	60 mg/kg	Rats	15 days	Reduction in glucose level
2010 91	Aqueous extract	Cinnamomum tamala	Leaf	125 mg/kg and 250 mg/kg body weight (twice a day)	Rats	20 days	Reduction in fasting blood glucose level and an increase in glycogen level