Cinnamon for Blood Sugar: Does It Work? What the Research Shows
TPBy the TrustedPurchaseReview Editorial Team
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The short answer
Cinnamon may modestly lower fasting blood sugar in people with type 2 diabetes, but the evidence is mixed. A 2024 meta analysis of 24 trials found lower fasting glucose and HbA1c, while an earlier analysis of 10 trials found lower fasting glucose but no significant change in HbA1c. The NIH says it is unclear whether cinnamon supplements help diabetes. The biggest safety issue is coumarin in cassia cinnamon: Germany’s food safety agency says about 2 grams a day of cassia can reach the safe limit for a 132 lb adult. Cinnamon does not replace diabetes medicine.
Cinnamon is one of the most common ingredients in blood sugar supplements. We read two meta analyses on type 2 diabetes, the NIH National Center for Complementary and Integrative Health page on cinnamon and the German Federal Institute for Risk Assessment (BfR) guidance on coumarin. This guide is general information, not medical advice.
Ceylon vs Cassia Cinnamon
| Type | Coumarin | What it means |
|---|---|---|
| Cassia (Cinnamomum cassia) | About 3,000 mg per kg on average, up to 10,000 mg per kg measured, according to the BfR | Fine in normal food amounts; daily use in larger amounts can exceed the safe coumarin limit |
| Ceylon (Cinnamomum verum) | Low levels, according to the BfR | The better choice if you use cinnamon every day; large amounts are still not advised in pregnancy |
What the Research Shows
| Review | What it covered | What it found |
|---|---|---|
| Allen et al., Annals of Family Medicine, 2013 | 10 randomized trials, 543 people with type 2 diabetes, 120 mg to 6 g a day for 4 to 18 weeks | Fasting glucose fell by about 25 mg/dL on average; HbA1c did not change significantly; cholesterol and triglycerides improved |
| Moridpour et al., Phytotherapy Research, 2024 | 24 randomized trials in type 2 diabetes | Significant reductions in fasting glucose, insulin resistance and HbA1c; no significant change in insulin |
| NIH (NCCIH), updated November 2024 | Summary of the research | It is unclear whether cinnamon supplements help diabetes or weight loss |
The two meta analyses point in the same direction for fasting glucose, but the 2013 authors warned that results varied widely between trials, the best dose and duration are unclear, and there were signs of publication bias, meaning positive studies may be more likely to be published. That is why the NIH stops short of recommending cinnamon for diabetes. The honest summary: a possible small effect on fasting blood sugar, not a treatment.
If you are comparing natural options, see our guides to berberine, chromium and gymnema.
Cinnamon Doses Used in Studies
The trials in the 2013 meta analysis used anywhere from 120 mg to 6 grams a day, for 4 to 18 weeks, and the authors could not identify an ideal dose. In that analysis, trials using capsules showed a significant HbA1c reduction while trials using powder did not.
If you use cassia cinnamon, the coumarin limit matters more than the study doses. The BfR tolerable daily intake is 0.1 mg of coumarin per kilogram of body weight:
| Body weight | Coumarin limit per day | Cassia that reaches it (at 3,000 mg/kg) |
|---|---|---|
| 33 lb (15 kg) child | 1.5 mg | About 0.5 g |
| 132 lb (60 kg) | 6 mg | About 2 g |
| 176 lb (80 kg) | 8 mg | About 2.7 g |
Cassia with more coumarin than average reaches the limit with less. The BfR considers going over the limit for one to two weeks to be safe.
Coumarin and the Liver
According to the BfR, liver problems linked to coumarin were seen in a small group of sensitive people who took coumarin as a medicine for several weeks. Mild cases raised liver enzymes; severe cases caused liver inflammation, usually reversible. The BfR notes that no liver damage from eating cinnamon has been described. The NIH adds that prolonged use of cassia could be an issue for sensitive people, such as those with liver disease.
Safety and Medicines
The NIH says cinnamon is likely safe in the amounts used in food, but larger amounts or long term use are sometimes linked to side effects.
Before you start
If you take any medicine, especially for diabetes, talk with your doctor before using cinnamon supplements. If you are pregnant, the NIH considers larger amounts of Ceylon cinnamon unsafe. If you have liver disease, avoid regular use of cassia.
Who Might Try Cinnamon?
May be reasonable if you
- Have prediabetes or type 2 diabetes and your doctor agrees
- Want a food based option alongside diet and exercise
- Choose Ceylon cinnamon or a product that states its coumarin content
Skip it or ask first if you
- Have liver disease
- Are pregnant
- Expect it to replace your diabetes medicine
Cinnamon Label Checklist
- Type. Look for Ceylon (Cinnamomum verum) or cassia (Cinnamomum cassia) on the label; “cinnamon” alone does not tell you the coumarin level.
- Amount per serving. In mg or grams, not hidden inside a proprietary blend.
- Powder or extract. Extracts are concentrated, so compare with the doses above carefully.
- Other blood sugar ingredients. Berberine, chromium or gymnema also target blood sugar, so check the full formula with your doctor.
- Claims. Be wary of promises to “reverse” diabetes or replace medication.
FAQ
Does cinnamon lower blood sugar?
How much cinnamon per day for blood sugar?
Is Ceylon or cassia cinnamon better?
Is cinnamon bad for your liver?
Can I take cinnamon with diabetes medicine?
⭐ Our pick for blood sugar
We have not yet reviewed a cinnamon supplement we can recommend. If you are looking at natural options for blood sugar, this is the product we reviewed that matches the dose used in studies.
Insulin Herb Berberine 6/10
500 mg of berberine per capsule, for the 1,000 to 1,500 mg a day used in studies, sold as a one time purchase with a 90 day guarantee. Talk to your doctor first if you take diabetes medicine.
Sources
- NIH National Center for Complementary and Integrative Health: Cinnamon: Usefulness and Safety, updated November 2024.
- German Federal Institute for Risk Assessment (BfR): FAQ on coumarin in cinnamon and other foods.
- Allen RW, et al. Cinnamon Use in Type 2 Diabetes: An Updated Systematic Review and Meta-Analysis. Annals of Family Medicine, 2013.
- Moridpour AH, et al. The effect of cinnamon supplementation on glycemic control in patients with type 2 diabetes mellitus: An updated systematic review and dose-response meta-analysis of randomized controlled trials. Phytotherapy Research, 2024.
About the editorial team
Written by the TrustedPurchaseReview editorial team. We read official labels and sales pages and check them against published research and government sources. We do not buy or test the products ourselves. We earn affiliate commissions on some links, and ratings are not for sale.
Questions or corrections? Contact us.
This guide is informational and not medical advice. Talk to your doctor before starting supplements, especially if you have diabetes or take medicine.