High-dose Cinnamon May Help Lower Blood Sugar (But First, Some History)

Taking a cinnamon supplement may help with blood glucose levels, and slow progression from pre-diabetes to type 2 diabetes.

Today, we look at new research supporting the use of the spice cinnamon to lower blood sugar. Let’s look back at the spice’s origin and history before we get to this exciting news.

True cinnamon (Cinnamomum zeylanicum) is native to Sri Lanka and has a long history. Egypt imported it, including for use in the embalming process. Gaius Plinius Secundus, more commonly known as Pliny, the Elder served as an author, natural philosopher, naturalist, and Roman Empire commander. Here is what Pliny the Elder observed about cinnamon in the first century A.D. :

Three hundred fifty grams of cinnamon is equal in value to over five kilograms of silver, about fifteen times the amount of silver per weight.

Medieval physicians used cinnamon as medicine

Cinnamon, as a medicinal agent, has historical roots. Indeed, physicians in medieval times offered it for cough, hoarseness, and sore throat. Roman Emperor Nero demanded that a year’s cinnamon supply be burned, in penance for his murdering his wife.

The Dutch seized cinnamon supplier Ceylon (modern-day Sri Lanka)

In the 1600s, the Dutch captured Ceylon from the Portuguese. The island led the world in cinnamon production, and the Netherlands established special quotas from the laborers. They then ensured that they had a monopoly on the cinnamon supply, demanding that the local king destroy a potentially competitive cinnamon source on the Indian coast.

The battles continued. The French conquered Holland during the Revolutionary Wars, earning them the prized Ceylon. In 1795, however, the English grabbed Ceylon from the French. Alas, by the early 1800s, the cinnamon monopoly had begun to collapse. Today, a host of tropical lands cultivate the valued spice.

Is cinnamon more than just a spice?

Could our medieval predecessors have been right about cinnamon having medicinal properties? Can taking high-dose cinnamon help to prevent type 2 diabetes? Let’s look at an intriguing new study, recently published in the Journal of the Endocrine Society.

Dr. Giulio Romeo and colleagues at Harvard Medical School recruited just over 50 adults from Kyung Hee University Medical Center (Seoul, Korea) and from the Joslin Diabetes Center (Boston, USA) from 2017 to 2018.

Each study subject had pre-diabetes. We mean that they had a fasting blood sugar level between 100 and 125 milligrams per deciliter. They also had other pre-diabetes indicators, such as impaired glucose tolerance, or a blood test showing a hemoglobin A1c level (a measure of our average blood sugar over the last three months) between 5.7 percent and 6.4 percent.

Cinnamon versus placebo for 12 weeks

The scientists randomized the participants into two groups: 1) 27 subjects consumed a cinnamon capsule thrice daily for 12 weeks; or 2) 24 subjects took a placebo (inert) for 12 weeks. The cinnamon capsules include 300 milligrams of cinnamon extract and 200 milligrams of Cinnamomum burmannii powder. For the placebo, the researchers added caramel food coloring and cinnamon incense.

At 6- and 12-week follow-up visits, researchers determined adherence through counting capsules returned by the participants and self-reporting. They recorded data on anthropometric measures, HbA1c, FPG, OGTT, fasting insulin, and fasting lipids.

Results: The placebo group had higher blood sugar levels

Before the intervention, the fasting blood sugar (glucose) levels between the cinnamon and placebo groups appeared similar. But at 12 weeks:

  • The placebo group had an average increase in fasting blood sugar levels of 4.5 milligrams per deciliter.
  • The cinnamon group had no change in fasting blood sugar levels.
  • The average difference in blood sugars was 114 for the placebo group, and 108 for the cinnamon group.

The change in hemoglobin A1c proved less impressive: The cinnamon group dropped HbA1c by 0.13 percent from study start to the 12-week mark; the placebo group differed by only 0.2 percent. But for those who had a hemoglobin A1c between 5.7 and 6.4 percent at study start, half of the cinnamon consumers dropped below 5.7 percent, while only one in the placebo group did.

Takeaway message

A cinnamon supplement might slow (or prevent) progression from pre-diabetes to diabetes. Alternatively, some adults with pre-diabetes might be able to achieve normal blood sugar status with cinnamon supplementation.

Of course, we need to confirm these results in more extensive studies (with longer follow-up). And we should not forget the role of more traditional lifestyle interventions — including physical activity and optimal weight — for risk-reduction.

Fortunately, the study showed no differences in side effects when comparing the cinnamon intervention with placebo. Thank you for joining me today. I’m Dr. Michael Hunter.


I have degrees from Harvard, Yale, and Penn. I am a radiation oncologist in the Seattle area. You may find me regularly posting at

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