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Cinnamon (Cinnamomum verum / Cinnamomum cassia)
A polyphenol-rich spice studied mainly for modest improvements in blood sugar and blood lipids; choose Ceylon to limit coumarin.
What the evidence says
Cinnamon doesn't have enough studies with structured effect-size data yet to pool a verdict. Browse the studies below for individual findings.
Most evidence is from high-quality meta-analyses and randomised trials published 2003–2026 with a typical study size of 647 participants.
Based on 128 studies · 32 meta-analyses · 58 RCTs · 7,132 total participants
Confidence
High confidenceBy outcome
13 more outcomes with fewer studies not shown.
Numerous meta-analyses consistently show modest reductions in fasting glucose and blood lipids in type 2 diabetes, but effects are small, heterogeneous between trials, and a rigorous RCT found no LDL benefit.
53 randomised trials
84% were about Cinnamon in an audit of 50 of them
Every randomised or controlled trial of Cinnamon indexed in PubMed, not a hand-picked subset. Meta-analyses and systematic reviews are deliberately excluded from this count: most of them cover many compounds at once, so counting them would inflate it.
PubMed · as of Sep 2026
23 trials ongoing or recruiting · 83 completed on ClinicalTrials.gov
5 of the completed trials have posted results
Registered trials show research momentum for Cinnamon, not proof of effect — a registration is a plan, and posted results are sponsor-reported, not peer-reviewed. They are never counted toward the evidence rating above.
Browse these trials on ClinicalTrials.govClinicalTrials.gov · as of Oct 2026
Cinnamon is the dried inner bark of Cinnamomum trees, used both as a culinary spice and a supplement.
Its polyphenols (notably cinnamaldehyde and procyanidins) are studied for supporting insulin sensitivity and glucose metabolism, with a large body of randomized trials and meta-analyses showing modest, somewhat heterogeneous reductions in fasting blood glucose and blood lipids.
Two main types are sold: Ceylon ('true' cinnamon, Cinnamomum verum) and the more common Cassia (Cinnamomum cassia). Cassia is much higher in coumarin, a compound that can stress the liver at high intakes, so Ceylon is preferred for regular supplemental use.
Cinnamon polyphenols improve insulin receptor sensitivity and glucose uptake in peripheral tissues.
Inhibits intestinal alpha-glucosidase and alpha-amylase, blunting post-meal glucose spikes.
Cinnamaldehyde and procyanidins reduce oxidative stress that contributes to insulin resistance.
Modulates cholesterol and triglyceride handling, contributing to small improvements in blood lipids.
Culinary amounts are fine; avoid concentrated supplemental doses without medical advice.
Monitor blood glucose; coordinate with your clinician to avoid hypoglycemia.
Prefer low-coumarin Ceylon and avoid high Cassia doses.
Additive blood-sugar lowering — monitor for hypoglycemia and adjust as needed with your clinician.
High-coumarin Cassia may add to bleeding risk; Ceylon is lower risk.
High-dose Cassia coumarin may add to liver stress.
Tip: Take with food; reduce dose; use extract
Tip: Use capsules or mix into food
Tip: Use Ceylon; avoid prolonged high Cassia doses
Cinnamon has an evidence score of 6.8/10 — moderate evidence based on 128 indexed studies, including 15 meta-analyses. A polyphenol-rich spice studied mainly for modest improvements in blood sugar and blood lipids; choose Ceylon to limit coumarin. Representative study: PMID 37818728.
The commonly studied dose of Cinnamon is 1,000 mg (1 g) cinnamon powder daily, or 250-500 mg standardized extract. Prefer Ceylon for regular use. The cited type 2 diabetes trial used 500 mg bark powder capsules, two a day. Label products go up to 6 g of powder a day, a figure from the ranges of the cited meta-analyses but not the dose of any cited trial. A cited dose-response meta-analysis found fat mass fell only at 2 g a day or more taken for at least 12 weeks. Individual needs vary — start at the lower end of the range and adjust based on how you respond.
The best time to take Cinnamon is with meals. Taking it with food is preferred. Taken with carbohydrate-containing meals to blunt post-meal glucose spikes; splitting across meals is common.
Cinnamon has a safety rating of "moderate". That is a category, not a measure of individual risk, and there are precautions worth knowing. Reported side effects include liver enzyme elevation (high-dose Cassia, coumarin), mild GI upset / heartburn, mouth irritation (with powder). How often they occur is not established for all of them. Use caution if any of these apply to you: Liver disease (especially with high-coumarin Cassia); Known cinnamon or balsam of Peru allergy.
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Reviewed by Dr. Baher Al Hakim · Last reviewed June 2026 · evidence from 128 studies · how we score · editorial policy
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.