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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
Most Cinnamon studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from high-quality meta-analyses and randomised trials published 2003–2026 with a typical study size of 140 participants.
Based on 102 studies · 31 meta-analyses · 54 RCTs · 1,036 total participants
Confidence
High confidenceBy outcome
10 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.
89 rigorous studies
53 randomized trials · 28 meta-analyses · 32 systematic reviews
Our evidence rating for Cinnamon is accountable to this entire body of rigorous research indexed in PubMed — not a hand-picked subset.
PubMed · as of Jul 2026
21 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momentum for Cinnamon, not proof of effect — a registration is a plan, and posted results are sponsor-reported, not peer-reviewed.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 Sep 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 78 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 1000-6000mg (1-6g) cinnamon powder daily, or 250-500mg standardized extract; prefer Ceylon for regular use. 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 is generally safe at recommended doses, with a few precautions worth noting. Reported side effects are uncommon and include mild GI upset / heartburn, mouth irritation (with powder), liver enzyme elevation (high-dose Cassia, coumarin). 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 102 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.