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Cinnamon Coumarin: What It Is and When It Matters
Cinnamon coumarin is a natural compound found in cassia cinnamon, the common supermarket kind. NCCIH notes that cassia contains coumarin, which may worsen liver disease. Large daily amounts over time are the concern, not a sprinkle on oatmeal. GLPro names no cinnamon on any published page, so the question cannot be applied to it.
Written by the GLPro label deskUpdated · 4 min read
01The compound
What is coumarin in cinnamon?
Coumarin is a fragrant plant compound that occurs naturally in several spices. In cinnamon it is found in meaningful amounts in the cassia types, which are the most common ones sold in grocery stores.
NCCIH points out that cassia contains coumarin, which may worsen liver disease (NCCIH, Diabetes and Dietary Supplements). The worry is about regular, larger intake over time, particularly in people with liver conditions or those who take medicines that strain the liver.
Food regulators in Europe have set a tolerable daily intake for coumarin based on body weight, which shows how seriously the compound is treated. A cinnamon roll now and then is far from that level.
Coumarin is also not the whole story of cinnamon. The spice has been used in food for centuries, and food amounts are not the topic here. The question is only what happens when a spice is turned into a daily capsule with a health claim attached.
02Supplements
Why does cinnamon coumarin matter more in a supplement?
It matters more in a supplement because a capsule can pack much more cinnamon than a meal does, and it can be taken every day. Trials of cinnamon for blood sugar often used about 2 grams a day of mostly cassia for four to sixteen weeks (Cochrane, cinnamon for diabetes).
Those trials gave unclear results. Cochrane found the evidence insufficient to support cinnamon for diabetes, with high risk of bias in most studies. A later meta-analysis of 16 trials reported a lower fasting glucose in treated groups but no change in A1C, and the results varied a lot (Deyno 2019, cinnamon meta-analysis).
| Point | Spice jar | Supplement |
|---|---|---|
| Typical amount | A pinch to a teaspoon | Often grams a day in trials |
| How often | Occasional | Daily for weeks |
| Type usually stated | Often not | Should be named on the panel |
| Coumarin shown | No | Rarely |
The American Diabetes Association does not recommend cinnamon for glycemic benefit (ADA Standards of Care 2026, Health Behaviors). In short, the benefit is unproven and the compound has a known caution, so the balance favors asking a clinician before buying.
03Who is affected
Who should be careful with cinnamon supplements?
People with liver disease, people who drink heavily and people on medicines that affect the liver should ask a clinician first. So should anyone taking diabetes medicine, since a glucose-active product can add to a low reading (Mayo Clinic, diabetic hypoglycemia).
- Check whether the label names cassia or Ceylon.
- Check the amount per capsule and the capsules per day.
- Tell your pharmacist about every supplement.
- Stop and call a clinician if you notice yellow skin or eyes, dark urine or severe tiredness.
Our post on Ceylon vs cassia cinnamon explains how the two types differ. Supplements can interact with medicines and affect surgery, so tell providers about them well ahead (NCCIH, Using Supplements Wisely).
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See packs04GLPro
Does GLPro contain cinnamon?
That is not confirmed. GLPro's sales page says only "proprietary blend of natural ingredients" and names none. Lists on other websites that name cinnamon for GLPro are unverified, and we do not repeat them.
If your bottle prints cinnamon, look for the type and the amount. If it prints a blend with no amounts, the coumarin question cannot be answered from the label. Call the order desk at +1 (302) 200-3480 and ask. The cinnamon education page gives the wider evidence.
Keep taking prescribed medicine. A supplement is not a replacement for diabetes treatment.
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05FAQ
Cinnamon coumarin questions, answered
Q01Is cinnamon safe to eat every day?
In normal food amounts, most healthy adults are fine. The concern rises with large daily doses of cassia over time, or with liver disease. Ask a clinician if you plan to take cinnamon in capsules.
Q02Does Ceylon cinnamon have coumarin?
Ceylon cinnamon carries far less coumarin than cassia, though a trace can occur. A label that names the type is more useful than one that says only cinnamon.
Q03Can cinnamon supplements harm the liver?
NCCIH says cassia contains coumarin, which may worsen liver disease. People with a liver condition should avoid guessing and ask a clinician before using cinnamon capsules.
Q04Can I get coumarin from other foods?
It occurs in a few other plants, but cinnamon is the main dietary source people think of. Total exposure matters more than one food, so count supplements as well as spices.
Q05How do I know which cinnamon a supplement uses?
The Supplement Facts panel should name the species or the plant part used. If it says only cinnamon, or hides it inside a blend, ask the seller in writing and keep the reply with your order records.
06Who wrote this
Written and reviewed by
Pages built from the bottle images, the sales page and linked NIH, FDA, CDC, FTC and peer-reviewed sources.
Last updated . Read our editorial standards and how we check reviews. This website is run by a U.S. stocking partner for GLPro, not by the manufacturer. We earn money when you buy through our order links.
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More about GLPro
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Ready to try GLPro?
Check your medicines first, then pick a pack. Six bottles ship free and cost the least per bottle, and every pack carries the 60-day money-back guarantee.
- Secure checkout
- 60-day money-back guarantee
- Ships from the U.S.