Research Library

Independent science behind Ceylon cinnamon. Interested in the research on cinnamon? We've gathered peer-reviewed studies, reviews and agency sources published by leading research institutes and public health bodies, with a link to each original. This is not a comprehensive list. If you would like to share a relevant study with us, please email CustomerService@Stabilicinn.com.

How to read this library. Each entry describes what was studied: the design, who took part and what was measured. We include studies with mixed or null results as well as positive ones. Many studies used Cassia cinnamon or did not name the species, so we note the cinnamon type for each. These studies did not test Stabilicinn, and none of this research was done in cooperation with our company. It is entirely independent of Stabilicinn.

Last reviewed: November 2026.

Blood sugar and glucose metabolism research

Clinical trials, systematic reviews and meta-analyses examining cinnamon and blood glucose measures. Results across studies are mixed, and many trials used Cassia or did not name the species, so we list the species for each.

• The glycaemic outcomes of Cinnamon, a review of the experimental evidence and clinical trials
  Medagama AB. Nutrition Journal 14:108, 2015. Cinnamon type: Mixed (cassia and Ceylon studies reviewed).
  Narrative review of animal and human experimental studies and clinical trials examining cinnamon and blood glucose measures.

• Effect of Ground Cinnamon on Postprandial Blood Glucose Concentration in Normal-Weight and Obese Adults
  Magistrelli AM, Chezem JC. Journal of the Academy of Nutrition and Dietetics 112(11):1806–1809, 2012. Cinnamon type: Unspecified (ground cinnamon).
  Crossover trial in 30 adults aged 18–30 (15 normal-weight, 15 obese) who ate 50 g available carbohydrate as farina cereal with or without 6 g ground cinnamon; blood glucose was measured over 120 minutes.

• The potential of cinnamon to reduce blood glucose levels in patients with type 2 diabetes and insulin resistance
  Kirkham S, Akilen R, Sharma S, Tsiami A. Diabetes, Obesity and Metabolism 11(12):1100–1113, 2009. Cinnamon type: Mixed (C. verum and C. cassia).
  Systematic review of 8 randomized placebo-controlled trials published 2003–2008 (5 in type 2 diabetes, 3 in non-diabetic participants; N = 311) examining blood glucose and insulin sensitivity.

• Response to Akilen et al. Efficacy and safety of ‘true’ cinnamon (Cinnamomum zeylanicum) as a pharmaceutical agent in diabetes: a systematic review and meta-analysis
  Ranasinghe P et al. Diabetic Medicine 30(4):506–507, 2013. Cinnamon type: Ceylon.
  Letter in which the authors of the 2012 Ceylon cinnamon systematic review reply to a letter from Akilen et al. (Diabet Med 30(4):505–506) about their review.

• Cinnamon intake lowers fasting blood glucose: meta-analysis
  Davis PA, Yokoyama W. Journal of Medicinal Food 14(9):884–889, 2011. Cinnamon type: Unspecified (cinnamon or cinnamon extracts).
  Meta-analysis of 8 randomized placebo-controlled trials in adults with type 2 diabetes and/or prediabetes, with fasting blood glucose as the outcome.

• Cinnamon extract improves fasting blood glucose and glycosylated hemoglobin level in Chinese patients with type 2 diabetes
  Lu T et al. Nutrition Research 32(6):408–412, 2012. Cinnamon type: Unspecified (cinnamon extract).
  Randomized, double-blind, placebo-controlled trial in Chinese adults with type 2 diabetes taking gliclazide, measuring fasting blood glucose and HbA1c.

• Effects of a cinnamon extract on plasma glucose, HbA1c, and serum lipids in diabetes mellitus type 2
  Mang B et al. European Journal of Clinical Investigation 36(5):340–344, 2006. Cinnamon type: Unspecified (aqueous cinnamon extract).
  Randomized, double-blind, placebo-controlled trial in 79 adults with type 2 diabetes not using insulin, given an aqueous extract equivalent to about 3 g/day cinnamon or placebo for 4 months, measuring plasma glucose, HbA1c and lipids (mixed results: glucose changed, HbA1c and lipids did not differ significantly).

• Cinnamon Use in Type 2 Diabetes: An Updated Systematic Review and Meta-Analysis
  Allen RW et al. Annals of Family Medicine 11(5):452–459, 2013. Cinnamon type: Mixed / unspecified.
  Systematic review and meta-analysis of 10 randomized controlled trials (543 patients with type 2 diabetes) examining fasting glucose, HbA1c and lipid measures (no significant change in HbA1c was reported).

• Cinnamon Improves Glucose and Lipids of People With Type 2 Diabetes
  Khan A et al. Diabetes Care 26(12):3215–3218, 2003. Cinnamon type: Cassia.
  Randomized placebo-controlled trial in 60 adults with type 2 diabetes examining fasting glucose and lipids after 40 days of 1, 3 or 6 g/day cinnamon, followed by a 20-day washout.

• Influence of Cinnamon on Glycemic Control in Individuals With Prediabetes: A Randomized Controlled Trial
  Romeo GR et al. Journal of the Endocrine Society 4(11):bvaa094, 2020. Cinnamon type: Unspecified.
  Double-blind, placebo-controlled trial in 54 adults with prediabetes randomized to 500 mg cinnamon or placebo three times daily for 12 weeks, measuring fasting plasma glucose and oral glucose tolerance test responses.

• Efficacy and safety of ‘true’ cinnamon (Cinnamomum zeylanicum) as a pharmaceutical agent in diabetes: a systematic review and meta-analysis
  Ranasinghe P et al. Diabetic Medicine 29(12):1480–1492, 2012. Cinnamon type: Ceylon.
  Systematic review of studies on C. zeylanicum and glucose-related measures; it identified 16 in-vitro and animal studies and no human trials.

• Efficacy and Safety of Cinnamomum zeylanicum (Ceylon cinnamon) for diabetes mellitus: a randomized, double blind, placebo-controlled clinical trial
  Ranasinghe P et al. Diabetes & Metabolic Syndrome: Clinical Research & Reviews 19(12):103357, 2025. Cinnamon type: Ceylon.
  Randomized, double-blind, placebo-controlled trial of Ceylon cinnamon in adults with diabetes, with glycemic measures (blood glucose, HbA1c, insulin resistance) and safety markers indexed as outcomes.

• Ceylon cinnamon does not affect postprandial plasma glucose or insulin in subjects with impaired glucose tolerance
  Wickenberg J et al. British Journal of Nutrition 107(12):1845–1849, 2012. Cinnamon type: Ceylon.
  Crossover trial in 10 adults with impaired glucose tolerance comparing 6 g Ceylon cinnamon capsules with placebo during a 75 g oral glucose tolerance test, measuring plasma glucose and insulin over 0–180 minutes (null result).

• Cassia cinnamon does not change the insulin sensitivity or the liver enzymes in subjects with impaired glucose tolerance
  Wickenberg J et al. Nutrition Journal 13:96, 2014. Cinnamon type: Cassia.
  Randomized, double-blind, placebo-controlled trial in 21 adults with impaired glucose tolerance (17 completed), given 12 g/day cassia cinnamon (6 g twice daily) or placebo for 12 weeks, measuring insulin sensitivity by clamp and liver enzymes (null result).

• Cinnamon supplementation does not improve glycemic control in postmenopausal type 2 diabetes patients
  Vanschoonbeek K et al. Journal of Nutrition 136(4):977–980, 2006. Cinnamon type: Cassia.
  Placebo-controlled trial in 25 postmenopausal women with type 2 diabetes given 1.5 g/day C. cassia or placebo for 6 weeks, measuring insulin sensitivity, oral glucose tolerance and blood lipids (null result).

• Effectiveness of cinnamon for lowering hemoglobin A1C in patients with type 2 diabetes: a randomized, controlled trial
  Crawford P. Journal of the American Board of Family Medicine 22(5):507–512, 2009. Cinnamon type: Unspecified (cinnamon capsules).
  Open-label randomized trial in 109 adults with type 2 diabetes and HbA1c above 7.0%, comparing 1 g/day cinnamon capsules plus usual care with usual care alone for 90 days and measuring HbA1c change.

• Cinnamon for diabetes mellitus (Cochrane Review)
  Leach MJ, Kumar S. Cochrane Database of Systematic Reviews, CD007170, 2012. Cinnamon type: Mixed / unspecified.
  Cochrane systematic review of 10 randomized controlled trials (577 participants with type 1 or type 2 diabetes) examining blood glucose measures and adverse effects; the review judged the evidence inconclusive.

• 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
  Moridpour AH et al. Phytotherapy Research 38(1):117–130, 2024 (online 2023). Cinnamon type: Mixed / unspecified.
  Dose-response meta-analysis of randomized controlled trials in adults with type 2 diabetes examining fasting blood glucose, HOMA-IR, HbA1c and serum insulin (no significant change in serum insulin was reported).

• The Effect of Cinnamon on Glycolipid Metabolism: A Dose–Response Meta-Analysis of Randomized Controlled Trials
  Yu T et al. Nutrients 15(13):2983, 2023. Cinnamon type: Mixed / unspecified.
  Dose-response meta-analysis of randomized controlled trials in adults with type 2 diabetes examining fasting glucose, HbA1c and lipid measures (no significant effect on fasting glucose or HbA1c was reported).

• Effect of cinnamon spice on continuously monitored glycemic response in adults with prediabetes: a 4-week randomized controlled crossover trial
  Zelicha H et al. American Journal of Clinical Nutrition 119(3):649–657, 2024. Cinnamon type: Unspecified (cinnamon spice).
  Randomized, double-blind crossover trial in 18 adults with prediabetes and obesity comparing 4 g/day cinnamon with placebo for 4 weeks each, measuring 24-hour glucose by continuous glucose monitor and oral glucose tolerance test responses.

Ceylon vs. Cassia, coumarin and safety

Studies measuring coumarin in different cinnamon types, coumarin intake and safety assessments, and safety reviews of cinnamon use.

• Coumarin and cinnamaldehyde in cinnamon marketed in Italy: A natural chemical hazard?
  Lungarini S et al. Food Additives & Contaminants: Part A 25(11):1297–1305, 2008. Cinnamon type: Mixed (market samples; mostly cassia).
  Retail cinnamon products sold in Italy were analyzed for coumarin and cinnamaldehyde by HPLC-DAD and the results were compared with the EU coumarin limit.

• Risk assessment of coumarin using the bench mark dose (BMD) approach: Children in Norway which regularly eat oatmeal porridge with cinnamon may exceed the TDI for coumarin with several folds
  Fotland TØ et al. Food and Chemical Toxicology 50(3–4):903–912, 2012 (online 2011). Cinnamon type: Unspecified (cinnamon in foods).
  Re-assessment of coumarin toxicity using the benchmark dose approach to derive a tolerable daily intake (TDI), with estimates of coumarin intake from cinnamon-containing foods in the Norwegian population.

• Cassia Cinnamon as a Source of Coumarin in Cinnamon-Flavored Food and Food Supplements in the United States
  Wang YH et al. Journal of Agricultural and Food Chemistry 61(18):4470–4476, 2013. Cinnamon type: Ceylon and cassia compared.
  Analysis of coumarin in authenticated cinnamon bark samples and US cinnamon-flavored foods and supplements, comparing true cinnamon with cassia-type barks.

• Quantification of flavoring constituents in cinnamon: high variation of coumarin in cassia bark from the German retail market and in authentic samples from Indonesia
  Woehrlin F et al. Journal of Agricultural and Food Chemistry 58(19):10568–10575, 2010. Cinnamon type: Cassia.
  HPLC analysis of coumarin and other flavor compounds in cassia bark from German retail and authentic Indonesian samples, including variation within single trees.

• Quantification of coumarin and related phenolics in cinnamon samples from south India using UHPLC-ESI-QqQLIT-MS/MS method
  Ananthakrishnan R et al. International Journal of Food Properties 21(1):50–57, 2018. Cinnamon type: Ceylon and market samples compared.
  UHPLC-MS/MS measurement of coumarin and related phenolics in authentic C. verum bark and market cinnamon samples from south India.

• Relative bioavailability of coumarin from cinnamon and cinnamon-containing foods compared to isolated coumarin: A four-way crossover study in human volunteers
  Abraham K et al. Molecular Nutrition & Food Research 55(4):644–653, 2011 (online 2010). Cinnamon type: Cassia.
  Four-way crossover study in 24 healthy volunteers comparing coumarin absorption from cinnamon-containing foods with isolated coumarin, using urinary and plasma 7-hydroxycoumarin as markers.

• Safety of Cinnamon: An Umbrella Review of Meta-Analyses and Systematic Reviews of Randomized Clinical Trials
  Gu DT et al. Frontiers in Pharmacology 12:790901, 2022. Cinnamon type: Mixed / unspecified.
  Umbrella review of 3 meta-analyses and 1 systematic review of randomized trials, examining adverse events and liver enzymes reported with cinnamon.

• Cinnamon: A systematic review of adverse events
  Hajimonfarednejad M et al. Clinical Nutrition 38(2):594–602, 2019 (online 2018). Cinnamon type: Mixed / unspecified.
  Systematic review of adverse events reported with cinnamon use in clinical studies and case reports, including allergic and gastrointestinal reactions.

• Evaluation of pharmacodynamic properties and safety of Cinnamomum zeylanicum (Ceylon cinnamon) in healthy adults: a phase I clinical trial
  Ranasinghe P et al. BMC Complementary and Alternative Medicine 17:550, 2017. Cinnamon type: Ceylon.
  Three-month phase I trial in 30 healthy adults (28 completed) given a water extract of Ceylon cinnamon at monthly escalating doses of 85, 250 and 500 mg/day, with liver and kidney function, blood counts, blood pressure and lipids monitored.

Composition and bioactive compounds

Studies and reviews on the chemistry of cinnamon: polyphenols, procyanidins, essential oils and how compounds are absorbed.

• Cinnamon Polyphenol Extract Regulates Tristetraprolin and Related Gene Expression in Mouse Adipocytes
  Cao H, Anderson RA. Journal of Agricultural and Food Chemistry 59(6):2739–2744, 2011. Cinnamon type: Unspecified (cinnamon polyphenol extract).
  Cell-culture study in mouse 3T3-L1 adipocytes measuring how a cinnamon polyphenol extract changed the expression of tristetraprolin and related inflammation-associated genes.

• Isolation and Characterization of Polyphenol Type-A Polymers from Cinnamon with Insulin-like Biological Activity
  Anderson RA et al. Journal of Agricultural and Food Chemistry 52(1):65–70, 2004 (online 2003). Cinnamon type: Unspecified.
  Laboratory isolation and structural characterization (catechin/epicatechin type-A oligomers) of water-soluble cinnamon polyphenol polymers, tested in cell-based insulin-signaling and antioxidant assays.

• New identification of proanthocyanidins in cinnamon (Cinnamomum zeylanicum L.) using MALDI-TOF/TOF mass spectrometry
  Mateos-Martín ML et al. Analytical and Bioanalytical Chemistry 402(3):1327–1336, 2012 (online 2011). Cinnamon type: Ceylon.
  Mass-spectrometry (MALDI-TOF/TOF) identification and structural characterization of proanthocyanidins in Ceylon cinnamon bark.

• Chemistry, biogenesis, and biological activities of Cinnamomum zeylanicum
  Jayaprakasha GK, Rao LJ. Critical Reviews in Food Science and Nutrition 51(6):547–562, 2011. Cinnamon type: Ceylon.
  Review of the chemical composition of Ceylon cinnamon oils and extracts, how the main constituents are formed in the plant, and their reported antioxidant, antimicrobial and other activities in laboratory studies.

• Medicinal properties of ‘true’ cinnamon (Cinnamomum zeylanicum): a systematic review
  Ranasinghe P et al. BMC Complementary and Alternative Medicine 13:275, 2013. Cinnamon type: Ceylon.
  Systematic review of about 70 in-vitro, animal and human studies of C. zeylanicum, including antioxidant, antimicrobial and anti-inflammatory activity; the authors note that randomized human trials were lacking.

• Cinnamomum Species: Bridging Phytochemistry Knowledge, Pharmacological Properties and Toxicological Safety for Health Benefits
  Sharifi-Rad J et al. Frontiers in Pharmacology 12:600139, 2021. Cinnamon type: Mixed (multiple Cinnamomum species).
  Review of the chemical constituents of Cinnamomum species, preclinical and clinical pharmacology studies, and toxicological safety data.

• Quantification of metabolite cinnamic acid of cinnamon (Cinnamomum zeylanicum) in human plasma
  Pigera S et al. Journal of the National Science Foundation of Sri Lanka 51(1):13–19, 2023. Cinnamon type: Ceylon.
  Development and validation of an HPLC-UV method for cinnamic acid in plasma, applied in a pharmacokinetic study of a single 5 g oral dose of Ceylon cinnamon in 5 healthy volunteers.

• “Ceylon cinnamon”: Much more than just a spice
  Suriyagoda L et al. Plants, People, Planet 3(4):319–336, 2021. Cinnamon type: Ceylon.
  Review of Sri Lankan Ceylon cinnamon covering its economic importance and production, bioactive constituents, food and industrial uses, quality testing and crop-breeding prospects.

Government and agency sources

Fact sheets and scientific opinions from public health and food safety agencies.

• Cinnamon: Usefulness and Safety (fact sheet)
  National Center for Complementary and Integrative Health (NCCIH), US National Institutes of Health. Government fact sheet, updated Nov 2024. Cinnamon type: Ceylon and cassia discussed.
  Consumer fact sheet summarizing research status, safety, coumarin content of cassia vs Ceylon, and drug-interaction and pregnancy cautions. It states that research does not clearly support cinnamon for any health condition.

• Coumarin in flavourings and other food ingredients with flavouring properties (Scientific Opinion)
  European Food Safety Authority (EFSA). EFSA Journal 6(10):793, 2008. Cinnamon type: Not species-specific.
  EFSA scientific opinion on coumarin toxicity and dietary exposure, confirming a tolerable daily intake of 0.1 mg/kg body weight.

• FAQ on coumarin in cinnamon and other foods
  German Federal Institute for Risk Assessment (BfR). Agency FAQ, 2012. Cinnamon type: Ceylon and cassia compared.
  Agency Q&A setting out the coumarin TDI (0.1 mg/kg body weight per day) and comparing coumarin levels in cassia (about 3,000 mg/kg on average, up to about 10,000 mg/kg) with Ceylon cinnamon (low levels).

Study titles and descriptions are provided for educational purposes and refer to the research as published. They are not claims about Stabilicinn. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Related: Glossary · What is coumarin? · Cinnamon polyphenols, explained