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Cinnamon is a spice obtained by drying the inner bark of the evergreen cinnamon tree. There are several types of cinnamon that differ in appearance, taste, and composition. Cinnamonum cassia, the most common type of cinnamon and the one that was clinically evaluated for its ability to lower blood glucose, is dark and spicy. Cinnamonum verum, or Ceylon cinnamon, is lighter, milder and sweeter tasting. More importantly, these two kinds of cinnamon differ in the amount of coumarin they contain. Coumarin is a fragrant compound that causes liver toxicity in high doses. While cinnamon cassia contains considerable amounts of coumarin (enough to make Denmark limit the amount of cinnamon used in their national specialty, cinnamon swirls!), Ceylon cinnamon contains only trace amounts of it. Although more expensive, Ceylon cinnamon seems like a safer alternative to cassia. Ceylon cinnamon has shown promising results in lowering blood glucose in animals but has not yet been clinically tested in humans.


Clinical trials that investigated the use of cinnamon for glycemic and lipid control have been rather small in size and provided conflicting results. The most recent review of 1o clinical trials (543 participants combined) suggested cinnamon's efficacy in lowering blood glucose and triglyceride levels in patients with type 2 diabetes.  However, it is not clear from these studies how much cinnamon patients should be taking and for how long to achieve these benefits.  


Cinnamon water extract has shown efficacy in lowering fasting blood glucose as well as systolic blood pressure in a small group of prediabetic men and women with metabolic syndrome.   The water extract has the advantage of delivering active ingredients while removing coumarin as well as some other compounds that act as allergens.

How to use


Because of the uncertainties associated with the dosing, length, and safety of cinnamon therapy, we believe that the use of cinnamon powder to lower blood glucose is not warranted at this time. Cinnamon, especially the Ceylon variety, can still be enjoyed in small amounts, as a spice.

Good quality Ceylon cinnamon


  • Frontier Co-op Organic Ceylon Cinnamon ground

A good way to obtain the benefits of cinnamon while minimizing the potential toxicity of coumarin is to make cinnamon tea (coumarin has low water solubility and is not easily extracted). Cinnamon tea can be made using either cinnamon sticks or the powder (although filtering off the powder can be messy). To make tea, add about one tablespoon of a cinnamon stick broken into pieces to one cup of hot water. Steep for about 10 minutes. Longer steeping times, as well as boiling cinnamon in water, will increase the amount of coumarin in the tea.


The dose of the cinnamon water extract most commonly used in clinical trials was 250 mg, administered twice a day (at breakfast and dinner). The longest duration of the therapy was 4 months.




The main concern with the excessive use of cinnamon is coumarin's liver toxicity. Cinnamon is also a known allergen.


Cinnamon tea for glycemic control
  • Spicely Organic True Cinnamon Sticks

Cinnamon water extract

  • Cinsulin, used in clinical trials

  • Doctor’s best​ Cinnamon Extract

Last updated: October 23, 2017

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