Ceylon Cinnamon
Complete evidence review for diabetes management
Evidence Rating
Limited Moderate Evidence
Summary
Cinnamon has shown modest glucose-lowering effects in some studies, but results are inconsistent. Meta-analyses show small reductions in fasting glucose (10-25 mg/dL) with minimal impact on A1C. Ceylon cinnamon is preferred over Cassia cinnamon due to lower coumarin content, which can be toxic to the liver at high doses. Overall evidence is weaker than other supplements in our database.
-0.1 to -0.2%
A1C Reduction
1-6g
daily
3
Key Studies
Modest
fasting glucose reduction
What is Ceylon Cinnamon?
Cinnamon contains polyphenols that may improve insulin sensitivity by enhancing insulin receptor function and increasing glucose uptake. It may also slow carbohydrate digestion by inhibiting digestive enzymes. However, the active compounds and optimal dose remain unclear.
Clinical Evidence
Key studies supporting Ceylon Cinnamon's use in diabetes management:
Khan et al. (2003)
60 patients with Type 2 diabetes. Cinnamon 1g, 3g, or 6g daily for 40 days. All doses reduced fasting glucose by 18-29% and improved lipid profile. Effects persisted 20 days after stopping.
Allen et al. (2013)
Cochrane meta-analysis of 10 RCTs with 577 participants. Cinnamon showed no significant effect on A1C or fasting glucose when all studies were pooled. High heterogeneity between studies noted.
Costello et al. (2016)
Meta-analysis of 11 RCTs. Cinnamon reduced fasting glucose by 25 mg/dL and had modest effects on lipids, but no significant effect on A1C. Authors noted poor quality of many included studies.
Drug Interactions
Critical Warning: Always consult your healthcare provider before combining Ceylon Cinnamon with any diabetes medication.
| Medication | Risk Level | Details |
|---|---|---|
| Diabetes medications | Low Risk | May have additive glucose-lowering effects, but effect is small. Monitor blood sugar. |
| Blood thinners (Warfarin) | Moderate | Cassia cinnamon contains coumarin, which has blood-thinning effects. Ceylon cinnamon is safer but still use caution. |
| Liver-metabolized drugs | Low Risk | Theoretical interaction via CYP enzymes, but clinical significance unclear. |
Dosage
The most studied protocol is 1-6g daily. Ceylon cinnamon (Cinnamomum verum) is essential - it has 1000x less coumarin than Cassia cinnamon. Look for 'true cinnamon' or 'Ceylon' on the label. Cassia is the common cinnamon in grocery stores and should be avoided for supplementation purposes.
Product Dosage Comparison
| Product | Dose per Capsule | Matches Studies? |
|---|---|---|
| Clinical trials | 1-6g daily (powder or capsules) | |
| Ceylon Cinnamon Shop | 500mg per capsule | |
| NOW Ceylon Cinnamon | 500mg per capsule | |
| Cassia cinnamon (common) | Varies |
Side Effects
| Side Effect | Frequency | Management |
|---|---|---|
| Mouth sores | 5% | Take capsules instead of powder. Reduce dose. |
| Allergic reactions | Rare | Discontinue if skin rash or irritation occurs |
| Liver damage (Cassia only) | Rare | Use Ceylon cinnamon, not Cassia. Avoid high doses long-term. |
Who Should NOT Take Ceylon Cinnamon
- Liver disease (especially with Cassia cinnamon)
- Allergy to cinnamon or balsam of Peru
- Pregnancy (high doses may stimulate uterus)
- Upcoming surgery (stop 2 weeks before due to blood-thinning effects)
Recommended Products
The following products meet our quality criteria. Links are affiliate links - see our affiliate disclosure.
Ceylon Cinnamon Shop Organic Ceylon Cinnamon
- Form: Organic Ceylon cinnamon, 500mg per capsule
- Third-party testing: USDA Organic, Non-GMO verified
- Dosage matches studies: Yes
- Notable: Verified true Ceylon cinnamon from Sri Lanka. Very low coumarin.
- Price: ~$15 for 120 capsules (60-day supply at 2/day)
NOW Ceylon Cinnamon
- Form: 500mg per capsule
- Third-party testing: GMP certified
- Dosage matches studies: Yes
- Price: ~$12 for 120 capsules
Want the complete supplement-medication interaction chart?
Download our free 42-page Diabetes Management Handbook, which includes a printable interaction chart for 8 supplements across all major diabetes medications.
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