Cinnamon
Also sold as: Ceylon cinnamon · Cinnamomum verum · Cassia cinnamon
Cinnamon bark and extracts are used as foods and marketed for glucose control. Potential metabolic effects vary across trials, while coumarin exposure depends strongly on species and product quality.
Longevity
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Research
- Longevity: Metabolic biomarker studies do not demonstrate longer life or prevention of cardiovascular events.
REALITY CHECK // Cinnamon does not replace metformin or other diabetes care. Positive metabolic meta-analyses coexist with an insufficient-evidence Cochrane conclusion, and none establishes a longevity benefit. Low-coumarin Ceylon products may reduce one hazard but are not automatically equivalent to the cassia preparations used in older trials.
Levels: how we grade evidence. Grey = evidence of no benefit; amber = evidence it makes this goal worse.
Ratings are self-reported by a self-selected group of users: how it felt, not proof that it works.
Check your bottle
Compare what your label says with what was used in trials. This is a trial range, not a personal prescription.
Enter the amount from your label to see the result.
How it was studied
UPPER LIMIT // No established cinnamon UL in this dossier. The relevant coumarin tolerable daily intake is 0.1 mg/kg body weight/day, equivalent to 6 mg/day for a 60 kg adult. This is a coumarin limit, not a cinnamon dose.
Summary
Trials in type 2 diabetes and prediabetes suggest possible reductions in fasting glucose, but reviews disagree and HbA1c findings are less consistent. Cochrane judged the evidence insufficient for diabetes treatment; a later meta-analysis reported fasting-glucose and lipid improvements. Healthy adults should not assume the same effects.
Mechanism
Polyphenols and cinnamaldehyde may influence insulin signalling and glucose handling. Proposed anti-inflammatory mechanisms and changes in surrogate markers do not establish disease prevention.
Typical studied dose
The extracted dossier discusses weeks-to-months trials of bark powders and extracts but does not provide a reliable preparation-specific numeric trial interval. No universal dose range is supplied here; powder, aqueous extract and species cannot be converted by name alone.
Upper limit
No established cinnamon UL in this dossier. The relevant coumarin tolerable daily intake is 0.1 mg/kg body weight/day, equivalent to 6 mg/day for a 60 kg adult. This is a coumarin limit, not a cinnamon dose.
Popular stacks with Cinnamon
Not enough stack data yet. A combination with Cinnamon appears here once 5 people rate the same set.
Forms and label traps
| Form on label | Active content | Studied range / day | Absorption & GI tolerance | Verdict |
|---|---|---|---|---|
| Ceylon cinnamon bark powder (C. verum) Best for: Reducing coumarin exposure relative to cassia. |
Unstandardized: active content unknown | no comparable trial range | No universal marker or trial-equivalent concentration. Usually tolerated as food; concentrated products differ. |
Good option [CHECK // GOOD] No active-dose conversion is justified. |
| Cassia cinnamon bark powder Best for: Identifying products requiring coumarin testing. |
Unstandardized: active content unknown | no comparable trial range | Used in many metabolic studies; coumarin content varies substantially. Coumarin-related liver risk matters with sustained high intake. |
Caution [CHECK // CAUTION] A stated 0.1-1% coumarin range is a safety concern, not an active ingredient target. Do not calculate a therapeutic coumarin dose. |
| Water-soluble cinnamon extract Best for: A product with declared extraction method and batch assay. |
Unstandardized: active content unknown | no comparable trial range | Enriched soluble fractions are not interchangeable with whole bark. Depends on preparation and residual compounds. |
Caution [CHECK // CAUTION] Water extraction alone does not demonstrate zero coumarin. Missing marker and trial interval prevent quantitative comparison. |
Common label traps
- TRAP_01 // CINNAMON REPLACES DIABETES MEDICINE
Trials and systematic reviews do not justify replacing prescribed treatment. - TRAP_02 // CEYLON AND CASSIA ARE THE SAME
Species differ in typical coumarin exposure; verify identity and testing rather than relying on a front-label claim. - TRAP_03 // WATER EXTRACT MEANS ZERO COUMARIN
Extraction may change composition, but residual coumarin requires analytical confirmation.
Other outcomes studied
Outside the five leaderboard goals. Same evidence levels as above.
- FASTING GLUCOSE Limited · benefit
Mixed meta-analyses in diabetes/prediabetes: possible benefit, with Cochrane finding insufficient evidence for treatment. No precise pooled effect is supplied in this extraction.
PMID 22972104 PMID 24019277 - PCOS METABOLIC MARKERS Limited · benefit
Small trials and heterogeneous reviews suggest possible insulin-resistance changes. Fertility benefit is not established.
PMID 29250843 PMID 32151755 - LIPIDS AND BLOOD PRESSURE Limited · benefit
Some reviews report modest changes in cardiometabolic populations; these are surrogate outcomes, not evidence of fewer cardiovascular events.
PMID 40611215 PMID 39299867
Reader questions
Is Ceylon the better choice?
It generally lowers coumarin exposure compared with cassia. That does not prove equal glucose effects, and authenticity should be independently checked.
Can I take it with metformin?
Discuss concentrated products with the prescriber and monitor as advised. Do not change diabetes medication to accommodate a supplement.
How much should I use for blood sugar?
A universal amount cannot be defended from the extracted preparation data. These trials are context, not an individualized treatment plan.
Stack interactions
- Caution Insulin and other glucose-lowering medicines [CAUTION // REVIEW_COMBINATION]
Possible additive glucose lowering warrants monitoring and prescriber review; a glucose trial is not a direct drug-interaction trial.
PMID 24019277 - Caution Liver disease / hepatotoxic medicines [CAUTION // REVIEW_COMBINATION]
Cassia can add coumarin exposure; individual susceptibility and total intake matter.
PMID 27378929 PMID 20024932
Red flags: interactions and who should avoid it
Interactions
Glucose-lowering medicines may have additive effects; discuss concentrated products with the diabetes team. Cassia-related liver exposure warrants caution with liver disease or hepatotoxic medicines. Direct anticoagulant interaction evidence is not established; coumarin content alone does not prove a warfarin-like effect.
Avoid or ask a doctor first if
Avoid concentrated or medicinal use without advice in pregnancy or breastfeeding, liver disease, or complex diabetes therapy. Stop and seek assessment for jaundice, dark urine or significant abdominal symptoms. Food use and concentrated supplements are different exposures.
Sources (PubMed, 10)
- Cinnamon for diabetes mellitus.
PMID 22972104 · 2012 · Systematic review / meta-analysisCochrane: insufficient evidence for diabetes treatment.
- Cinnamon use in type 2 diabetes: an updated systematic review and meta-analysis.
PMID 24019277 · 2013 · Systematic review / meta-analysisUpdated clinical-trial meta-analysis with fasting-glucose and lipid signals.
- The Relation between Hepatotoxicity and the Total Coumarin Intake from Traditional Japanese Medicines Containing Cinnamon Bark.
PMID 27378929 · 2016 · Cohort studyHuman cohort evidence concerning total coumarin exposure and liver toxicity.
- Toxicology and risk assessment of coumarin: focus on human data.
PMID 20024932 · 2010 · Narrative reviewCoumarin toxicology and human risk assessment.
- Effects of Cinnamomum zeylanicum (Ceylon cinnamon) extract on lipid profile, glucose levels and its safety in adults: A randomized, double-blind, controlled trial.
PMID 39854533 · 2025 · RCTCeylon-specific adult metabolic and safety trial.
- Efficacy and Safety of Cinnamomum zeylanicum (Ceylon cinnamon) for diabetes mellitus: a randomized, double blind, placebo-controlled clinical trial.
PMID 41412108 · 2025 · RCTCeylon-specific diabetes trial.
- The effect of cinnamon supplementation on cardiovascular risk factors in adults: a GRADE assessed systematic review, dose-response and meta-analysis of randomized controlled trials.
PMID 40611215 · 2025 · Systematic review / meta-analysisGRADE-assessed cardiometabolic meta-analysis.
- Insulin resistance improvement by cinnamon powder in polycystic ovary syndrome: A randomized double-blind placebo controlled clinical trial.
PMID 29250843 · 2018 · RCTPCOS insulin-resistance RCT.
- Effects of cinnamon on controlling metabolic parameters of polycystic ovary syndrome: A systematic review and meta-analysis.
PMID 32151755 · 2020 · Systematic review / meta-analysisPCOS metabolic systematic review.
- Effect of cinnamon supplementation on blood pressure, oxidative stress, and inflammatory biomarkers in adults: An umbrella review of the meta-analyses of randomized controlled trials.
PMID 39299867 · 2024 · Systematic review / meta-analysisUmbrella review of blood pressure and inflammatory biomarkers.
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