Ceylon cinnamon is often promoted as a natural way to support healthy blood sugar levels. You may have seen claims that it can lower blood glucose, improve insulin sensitivity, or help people with diabetes.
But how much of this is actually supported by research?
The short answer is: cinnamon may have a modest effect on blood sugar in some people, but the evidence is mixed, and there is not enough good evidence to say that Ceylon cinnamon can treat diabetes or reliably lower blood sugar.
There is another important detail. Many studies simply use the word “cinnamon” without clearly stating which species was tested. That makes it difficult to apply their findings specifically to Ceylon cinnamon.
What is Ceylon cinnamon?
Ceylon cinnamon is made from the bark of Cinnamomum verum, also known as Cinnamomum zeylanicum. It is sometimes called “true cinnamon” and is traditionally associated with Sri Lanka.
It is different from cassia cinnamon, which comes from related cinnamon species.
One of the main differences is their chemical composition. Cassia cinnamon can contain much more coumarin, a naturally occurring compound that can be a concern when large amounts are consumed regularly. Ceylon cinnamon generally contains only trace amounts of coumarin.
That difference is one reason people often choose Ceylon cinnamon for regular food use.
But it does not automatically mean that Ceylon cinnamon has a stronger effect on blood sugar.
Does Ceylon cinnamon lower blood sugar?
There is no simple yes-or-no answer.
Research on cinnamon as a whole has produced mixed results. Some clinical trials and reviews have found reductions in fasting blood glucose, while others have found little or no meaningful improvement.
A 2019 meta-analysis of 16 randomized controlled studies found that cinnamon supplementation reduced fasting blood glucose and insulin resistance in people with type 2 diabetes or prediabetes. However, the researchers also noted substantial differences between the studies.
A newer systematic review published in 2024 reached a similar general conclusion: some studies found positive effects, but the results became less convincing when study quality and risk of bias were taken into account. The authors described the possible benefit as modest.
So it would be too strong to say that cinnamon is proven to lower blood sugar.
What about Ceylon cinnamon specifically?
This is where things get more interesting.
Many cinnamon studies do not clearly identify the species of cinnamon used. Researchers may use cassia, Ceylon cinnamon, another species, or a cinnamon extract. Different products can also contain different amounts of active compounds.
Because of this, results from a study using cassia cinnamon cannot automatically be presented as proof that Ceylon cinnamon has the same effect. NCCIH specifically points out that differences between cinnamon species and the parts of the plant used make the research difficult to interpret.
There is also a clinical study that looked specifically at Ceylon cinnamon.
In that study, people with impaired glucose tolerance were given 6 grams of Ceylon cinnamon during an oral glucose tolerance test. The researchers found no significant effect on blood glucose, insulin response, glycemic index, or insulin index after the test.
That does not prove Ceylon cinnamon has no effect at all. It simply shows why claims about Ceylon cinnamon and blood sugar need to be made carefully.
What does the wider cinnamon research show?
The wider evidence is more encouraging, but still far from conclusive.
A 2023 meta-analysis of 24 randomized controlled trials found that cinnamon supplementation was associated with reductions in fasting blood sugar, insulin resistance and HbA1c in people with type 2 diabetes. However, the researchers were evaluating cinnamon supplementation in general, not Ceylon cinnamon alone.
Other reviews have found smaller or inconsistent effects.
For example, an earlier meta-analysis found that cinnamon reduced fasting plasma glucose but did not find a significant improvement in HbA1c. The researchers also highlighted the large differences between studies.
This matters because fasting blood sugar and HbA1c tell us different things.
A small change in fasting glucose does not necessarily mean that a person’s overall diabetes control has improved.
Why might cinnamon affect blood sugar?
Researchers have proposed several possible explanations.
Some laboratory and human research suggests that compounds in cinnamon may affect the way cells respond to insulin and how glucose is handled by the body.
Insulin normally helps move glucose from the bloodstream into cells, where it can be used for energy. When the body becomes less responsive to insulin, blood glucose can remain higher.
Cinnamon may influence some of these processes, but researchers still do not have a clear answer about how important these effects are in everyday life.
That is another reason to be cautious with claims that cinnamon “works like insulin” or “reverses insulin resistance.”
Those statements go further than the current human evidence allows.
Is Ceylon cinnamon better than cassia for blood sugar?
Not necessarily.
Ceylon cinnamon is often considered a better choice for regular culinary use because it contains much less coumarin than cassia cinnamon. But there is not enough evidence to say that Ceylon cinnamon is better than cassia specifically for lowering blood sugar.
In fact, one of the biggest problems with cinnamon research is that different species and preparations are often grouped together.
So these are two separate questions:
Which cinnamon has less coumarin?
Ceylon cinnamon generally has much less.
Which cinnamon is proven to lower blood sugar more?
We do not have enough reliable evidence to answer that.
Can people with diabetes eat Ceylon cinnamon?
For most people, using Ceylon cinnamon as a normal food spice is very different from taking large amounts as a supplement.
Cinnamon is generally considered safe when used in the amounts normally found in food. Larger amounts or long-term use can cause problems for some people, including digestive symptoms or allergic reactions.
If you have diabetes and take medication to lower your blood sugar, it is sensible to speak with your healthcare professional before taking cinnamon supplements regularly.
Cinnamon should not be used as a replacement for prescribed diabetes treatment.
The National Center for Complementary and Integrative Health also warns against products that claim to be a “natural diabetes cure” or say that they can replace diabetes medicine.
How can you use Ceylon cinnamon in your diet?
If you enjoy Ceylon cinnamon, there are simple ways to use it as a spice:
- Add it to oatmeal.
- Sprinkle it over plain yogurt.
- Add it to coffee or tea.
- Use it in a homemade smoothie.
- Add it to baked apples or other fruit.
- Use it in savory dishes where cinnamon fits the recipe.
The useful point here is not to treat cinnamon as medicine.
Instead, think of it as a flavorful spice that can be part of an overall healthy eating pattern.
For someone trying to manage blood sugar, the bigger picture matters much more than adding one ingredient to a meal. Food portions, carbohydrate intake, physical activity, sleep, medication and other lifestyle factors can all affect blood glucose.
How much Ceylon cinnamon should you take for blood sugar?
There is no well-established Ceylon-specific dose that can be recommended for lowering blood sugar.
Clinical studies have used very different amounts, cinnamon species and preparations. Some studies use cinnamon powder, while others use extracts or supplements. This makes it difficult to turn the research into one reliable daily dose.
For this reason, it is better not to assume that taking more cinnamon will produce a bigger benefit.
If you are considering a cinnamon supplement, especially if you have diabetes, take medication, have liver problems, or are pregnant, discuss it with a qualified healthcare professional first.
Can Ceylon cinnamon replace diabetes medicine?
No.
There is currently not enough evidence to use Ceylon cinnamon as a treatment for diabetes or as a replacement for prescribed medication.
Some studies suggest cinnamon may have a modest effect on certain blood sugar measurements, but the results are inconsistent. Major health organizations also say that the evidence is not strong enough to support cinnamon as a treatment for diabetes.
If you take diabetes medication, do not stop or change it because you started using cinnamon.
The bottom line
Ceylon cinnamon is an interesting food, but the claims about blood sugar are often stronger than the science.
Research on cinnamon suggests that it may modestly improve some blood sugar measurements in some people, particularly fasting blood glucose. However, studies have produced mixed results, and many do not clearly identify which type of cinnamon was used.
The evidence specifically on Ceylon cinnamon is much more limited. One human study found that Ceylon cinnamon did not significantly change post-meal glucose or insulin levels in people with impaired glucose tolerance.
So the most accurate answer is:
Ceylon cinnamon may be a useful spice to include in a healthy diet, but it should not be considered a proven treatment for high blood sugar or diabetes.
If you like the flavor, use it in food. If you are thinking about taking concentrated cinnamon supplements for blood sugar, talk with your healthcare professional first.
This article is for general educational purposes and is not a substitute for medical advice, diagnosis or treatment.