Monograph
Cinnamon
Cinnamomum verum
Updated October 4, 2026
Key points
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01
Ceylon or cassia?
Most cinnamon sold in North America is cassia. Ceylon cinnamon (C. verum) has only traces of coumarin; cassia can contain a lot. Labels often do not say which.
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02
Coumarin and the liver
EFSA’s tolerable intake is 0.1 mg coumarin per kg body weight daily. BfR calculates a 60 kg adult reaches it with about 2 g of cassia a day.
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03
Diabetes evidence is mixed
Meta-analyses find lower fasting glucose but no clear change in HbA1c. Cochrane found insufficient evidence, and a key early trial now has an expression of concern.
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04
A traditional digestive remedy
The EU accepts Ceylon cinnamon tea, 0.5–1 g up to four times daily, only as a traditional remedy for mild cramping, bloating, and mild diarrhoea.
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05
Allergy and the challenge
Cinnamaldehyde is a common contact allergen in gum and toothpaste. Never swallow spoonfuls of dry cinnamon: the cinnamon challenge risks inhaling powder and lung injury.
Cinnamon is a spice first and a medicine second, and the word on the label can mean several different trees. True or Ceylon cinnamon, Cinnamomum verum, grows primarily in Sri Lanka, while cassia, Cinnamomum aromaticum (also called C. cassia), grown in southeastern Asia, is the most common type sold in North America (NCCIH). Other cassias, including Indonesian C. burmannii, are also sold simply as cinnamon. As a medicine, the EU’s herbal committee accepts Ceylon cinnamon bark only as a traditional remedy for mild spasmodic digestive complaints such as bloating and flatulence, and for mild diarrhoea, on the basis of long use rather than clinical trials (European Medicines Agency).
Cinnamon’s modern fame comes from blood sugar. Supplements are promoted for type 2 diabetes and weight loss, yet the US National Center for Complementary and Integrative Health (NCCIH) concludes that research does not clearly support cinnamon for any health condition. A Cochrane review found insufficient evidence for diabetes, and meta-analyses that report lower fasting glucose generally find no change in HbA1c, the longer-term measure of blood sugar control. Most trials used cassia rather than Ceylon cinnamon, and one of the most cited early trials now carries a formal expression of concern.
The main safety issue is coumarin, a natural flavouring compound that is abundant in cassia but present only in traces in Ceylon cinnamon. In sensitive people, coumarin has caused liver damage. European food safety authorities set a tolerable daily intake of 0.1 mg per kg of body weight, and Germany’s Federal Institute for Risk Assessment (BfR) calculates that a 60 kg adult reaches it with about 2 g of cassia a day. Cinnamaldehyde, the compound behind cinnamon’s flavour, is also a well-known contact allergen, and the online “cinnamon challenge” has left teenagers needing medical attention. Nothing here is medical advice; diabetes needs proven treatment, and cinnamon supplements should not replace prescribed medicines.
In this monograph
01 The plant
Botanical profile
Ceylon cinnamon, Cinnamomum verum J. Presl, belongs to Lauraceae, the laurel family; Cinnamomum zeylanicum is a synonym (EMA), and NCCIH also lists the older name Laurus cinnamomum. NCCIH notes that the bark, leaves, flowers, fruits, and roots of cinnamon trees have all been used in traditional medicine, but the European Pharmacopoeia drug is specifically the dried bark of shoots grown on cut stock, freed from the outer cork and the underlying parenchyma. EMA’s assessment report describes it as matt pieces of bark 0.2–0.7 mm thick, rolled into single or double compound quills, light brown outside and somewhat darker inside, with a pungently spicy, slightly sweet and mucilaginous taste. The Pharmacopoeia requires at least 12 ml of essential oil per kg.
Cassia is the cinnamon most people actually buy. NCCIH notes that cassia, C. aromaticum, is the most common type in North America, and Wang and colleagues, analysing authenticated samples in 2013, noted that C. cassia, C. loureiroi, and C. burmannii, commonly known as cassia, are all sold as cinnamon in the US. EMA’s assessment explicitly excludes cassia, while noting that the two are comparable in composition. The difference that matters for safety is coumarin: Wang’s team found only traces in C. verum but substantial amounts in the cassias. BfR notes that as a powder, Ceylon and cassia are hardly possible for consumers to tell apart. As sticks, BfR explains, cassia is a single thick layer of bark rolled up, while Ceylon cinnamon looks like a cut cigar with many fine layers inside.
EMA reports that cinnamon bark contains up to 4% essential oil, made up mainly of cinnamaldehyde (60–75%), with eugenol (1–10%), cinnamyl acetate (1–5%), β-caryophyllene, linalool, and 1,8-cineole, along with procyanidins, cinnamic acid, and mucilage polysaccharides. Cinnamon bark oil may be adulterated with cheaper cinnamon leaf oil or cassia oil. Coumarin levels in cassia are high and variable: BfR gives an average of about 3,000 mg per kg of cassia powder, with up to 10,000 mg per kg in some samples, while Ceylon cinnamon contains very little.
02 Lineage
History
EMA’s assessment report calls cinnamon one of the herbal substances with the longest medicinal tradition. It was used in Egyptian embalming fluids, and in Ayurvedic medicine the bark was used against vomiting, diarrhoea, and flatulence. Cinnamon is mentioned in the Bible and by Greek and Roman writers including Theophrastus, Herodotus, Dioscorides, Galen, and Pliny, though none clearly names Ceylon as its source. Dioscorides described five kinds of cassia and seven of cinnamon, credited with diuretic and digestive properties. From the 8th century cinnamon reached Europe as an expensive spice, and a written report of 1310 confirmed cinnamon trees growing in Ceylon.
The spice shaped colonial history. The Portuguese found cinnamon growing in Sri Lanka in the early 16th century and shipped it to Europe; by one account, in 1536 Ceylon cinnamon cost 40 times as much as cinnamon from Java or the Philippines. The Dutch occupied the island from the mid-17th century, and cultivation, replacing collection from wild trees, began around 1765 under their control. When the British captured Sri Lanka in 1796, the cinnamon trade became a monopoly of the East India Company (EMA). Barceloux, cited by EMA, describes Sri Lanka as the only regular supplier of cinnamon bark and leaf oils today, and China as the main exporter of cassia.
Older European medicine used cinnamon as a stomachic for diarrhoea, dyspepsia, and bloating, and the 1938 German herbal of Madaus warned that higher doses could have an abortive effect. EMA notes that cinnamon was used as an abortifacient in antiquity and the Middle Ages, but that old sources confused cinnamon (cassia) with Cassia fistulosa, an unrelated plant containing anthraquinones. In the 2000s small trials of cassia, notably Khan’s 2003 study in Peshawar, Pakistan, reported lower blood sugar, and today cinnamon is promoted as a supplement for diabetes and weight loss (NCCIH). Regulators moved the other way on coumarin: BfR records that EU limits for coumarin in foods were revised from January 2011, allowing up to 50 mg per kg in traditional and seasonal bakery products such as cinnamon stars, and 5 mg per kg in desserts.
03 Chemistry
Active compounds and how it works
Cinnamaldehyde gives cinnamon its burn. In 2004 Ardem Patapoutian’s group showed that pungent compounds from cinnamon oil, wintergreen oil, clove oil, mustard oil, and ginger activate TRPA1, an ion channel on sensory nerves, and that cinnamaldehyde is the most specific of them, exciting a subset of cold-sensitive neurons (Bandell et al.). That explains the hot, prickling sensation of cinnamon gum and the irritation of concentrated oil. For digestion, EMA’s assessment cites laboratory studies showing papaverine-like spasm-relieving effects of cinnamon bark oil and cinnamaldehyde on guinea pig intestinal and airway muscle, and an anti-foaming effect on digestive fluids in vitro. EMA judges that these findings, obtained with high concentrations of oil, partly support the traditional use for cramps and wind.
How cinnamon might affect blood sugar is less clear. MSKCC summarises laboratory findings that a methylhydroxychalcone polymer isolated from cinnamon mimics insulin by activating insulin receptors, and that cinnamon inhibits the cholesterol-making enzyme HMG-CoA reductase in animals. Small human studies summarised by EMA found that 5 g of cassia blunted the rise in blood glucose after a glucose drink, and that 6 g taken with rice pudding slowed stomach emptying. Which species, extract, and constituent matter remains uncertain, and NCCIH notes that many studies do not say which kind of cinnamon or which part of the plant was used.
Coumarin is a separate story from cinnamaldehyde. BfR explains that coumarin given as a medicine has caused liver damage within weeks in a small group of particularly sensitive people, usually reversible once it is stopped, and that the tolerable daily intake protects these sensitive consumers too. Cinnamaldehyde itself depletes glutathione, a protective molecule in liver cells, in laboratory studies, which is why EMA’s assessment advises avoiding cinnamon oil by mouth in people with liver disease or alcoholism and in those taking paracetamol.
04 In practice
Common uses
Blood sugar in type 2 diabetes is the most studied use, and the results are mixed. Leach and Kumar’s 2012 Cochrane review pooled 10 randomised trials with 577 participants with type 1 or type 2 diabetes, mostly using C. cassia at a mean of 2 g a day for 4–16 weeks. The effect on fasting glucose was inconclusive, there was no significant difference in HbA1c, insulin, or blood sugar after meals, and the risk of bias was high or unclear. The authors concluded that there is insufficient evidence to support cinnamon for diabetes. Allen and colleagues’ 2013 meta-analysis of 10 trials in 543 people with type 2 diabetes, using 120 mg to 6 g a day for 4–18 weeks, found a fall in fasting glucose of 24.59 mg/dL, lower total cholesterol, LDL cholesterol, and triglycerides, and a small rise in HDL, but no significant effect on HbA1c (−0.16%), with very high heterogeneity between trials.
The species problem runs through this evidence. When EMA reviewed the literature again in 2020–2021, it noted that an earlier meta-analysis included mostly cassia trials, and that in Deyno and colleagues’ 2019 meta-analysis of 16 trials, which found lower fasting glucose and insulin resistance but no change in HbA1c or blood lipids, only three studies used C. verum, at 1–3 g a day in 214 patients. EMA concluded that the data did not justify adding any indication. Khan and colleagues’ 2003 trial, in which 60 people with type 2 diabetes took 1, 3, or 6 g of cassia daily for 40 days and saw fasting glucose fall by 18–29%, was a foundation of the cinnamon-for-diabetes idea; in 2025 Diabetes Care published an expression of concern about it, citing baseline differences inconsistent with randomisation, unclear blinding, possible statistical misreporting, no loss to follow-up, and authors who could not be reached.
For other uses the evidence is thinner still. NCCIH says it is unclear whether cinnamon helps with weight loss, and that a nasal spray containing Ceylon cinnamon extract for hay fever has only preliminary support. MSKCC notes meta-analyses suggesting reductions in triglycerides, total cholesterol, and C-reactive protein, and preliminary data in polycystic ovary syndrome, metabolic syndrome, and dental plaque, all needing better trials. Hajimonfarednejad and colleagues’ 2019 safety review concluded that cinnamon is safe as a spice, but that medicinal use in larger amounts or for longer should be monitored.
The EU’s traditional-use monograph (EMA/HMPC/246774/2009) is narrower and older in spirit: Ceylon cinnamon bark for the symptomatic treatment of mild spasmodic gastrointestinal complaints, including bloating and flatulence, and for mild diarrhoea. EMA’s assessment report is explicit that there are no clinical efficacy data for C. verum and that these indications rest on long-standing use. That is a reasonable basis for a cup of cinnamon tea after a heavy meal, and a poor basis for treating any chronic condition.
05 The apothecary
Preparations and traditional use
EMA’s monograph gives traditional doses for adults and the elderly. As a herbal tea, 0.5–1 g of cut bark is taken as an infusion up to four times a day, for either indication. For mild spasmodic digestive complaints, a liquid extract (1:1, 70% ethanol) is taken at 0.5–1 ml three times daily, or a tincture (1:5, 70% ethanol) at 2–4 ml a day. Use in under-18s is not recommended. If digestive complaints last longer than two weeks, or diarrhoea longer than two days, a doctor should be consulted; in diarrhoea, replacing fluids and salts comes first, and recurrent diarrhoea or blood in the stool needs medical assessment.
Supplements are another matter. Trials have used anywhere from 120 mg to 6 g a day (Allen et al.), and NCCIH warns that labels often do not specify the species. That matters because of coumarin. EFSA’s 2008 opinion confirmed a tolerable daily intake of 0.1 mg of coumarin per kg of body weight, and judged that exceeding it threefold for one to two weeks is not a safety concern. BfR calculates that a 60 kg adult reaches the limit with about 2 g of cassia a day, and a 15 kg child with about 0.5 g. BfR warns that supplements may contain high levels of coumarin, and Wang’s team detected coumarin in all the locally bought cinnamon, cinnamon-flavoured foods, and supplements they tested in the US. BfR advises people who eat a lot of cinnamon to choose Ceylon.
Cinnamon bark oil is far more concentrated. EMA’s assessment cites older references giving 50–200 mg of oil a day in divided doses, but notes that the oil and cinnamaldehyde are irritant above 0.2 g a day, roughly equivalent to 15–20 g of bark, and that the oil must be regarded as a potential skin sensitiser that should not be used on young children or the elderly. Undiluted oil should never be applied to the skin or swallowed. Dry cinnamon powder should never be eaten by the spoonful.
Safety
Before you use cinnamon
06 Caution
Side effects
In food amounts, cinnamon is likely safe for most people (NCCIH). Hajimonfarednejad and colleagues’ 2019 systematic review of cinnamon safety drew on 38 trials, only five of which reported adverse events, along with 20 case reports, 7 case series, and 160 spontaneous reports; the most frequent problems were digestive upset and allergic reactions, mostly self-limiting. The Cochrane diabetes review found adverse reactions infrequent and mild. NCCIH notes that taking larger amounts or using cinnamon for long periods sometimes causes gastrointestinal problems or allergic reactions.
Contact allergy is the best-documented problem. EMA’s assessment describes cinnamaldehyde as an irritant and sensitiser, and lists reactions to cinnamon in toothpastes, mouthwashes, chewing gum, drinks, and baked goods: contact dermatitis, perioral dermatitis, cheilitis, stomatitis, gingivitis, glossitis, chronic lichenoid mucositis, and contact urticaria, with rare immediate reactions such as asthma or hives. Cinnamon gum typically causes lesions on the side of the tongue or the inner cheek, while toothpaste causes diffuse inflammation of the gums. MSKCC adds plasma cell gingivitis from toothpaste and gum, occupational allergy to cinnamal in a baker, contact dermatitis from vaginal suppositories containing cinnamon oil, and widespread dermatitis in a 26-year-old after several cups of a tea rich in cinnamon. Second-degree burns followed 48 hours of skin contact with cinnamon oil in an 11-year-old boy (EMA).
Liver injury is the concern most people have heard about, and the picture is nuanced. BfR explains that coumarin given as a medicine has caused liver damage within weeks in a small group of sensitive people, ranging from raised liver enzymes to hepatitis with jaundice, usually reversible, but that no such cases following consumption of cinnamon had been described in the scientific literature. EMA’s 2021 review discussed a case of acute hepatitis in a 73-year-old woman who had started a cinnamon supplement while taking rosuvastatin; her symptoms settled when both were stopped, and she later resumed the statin without problems. It also discussed a Japanese study of patients taking cinnamon-containing Kampo medicines, in which no cases of abnormal liver function caused by cinnamon bark were seen among the 98 whose coumarin intake exceeded the tolerable daily intake. The tolerable intake remains the sensible guide.
The “cinnamon challenge”, swallowing a tablespoon of ground cinnamon within a minute without water, is dangerous. Bosmia and Leon report that calls about it to US poison centres among 13–19-year-olds rose from 51 in 2011 to 222 in 2012, and that of 122 calls about intentional misuse in the first three months of 2012, 30 needed medical attention. The powder dries out the mouth, making it very hard to swallow, and provokes coughing and burning; it can be inhaled, and its cellulose fibres neither dissolve nor break down in the lungs. More serious effects include vomiting, nosebleeds, chest tightness, and collapsed lung segments (atelectasis), with higher risk in people with asthma or other breathing problems. A 2013 Pediatrics commentary by Grant-Alfieri and colleagues warned against the dare, and NCCIH says plainly never to try it. Swallowing cinnamon oil can also cause drowsiness that predisposes to aspiration pneumonia (EMA).
07 Caution
Contraindications
Allergy: people who are allergic to cinnamon or to Peru balsam should not use medicinal cinnamon (EMA). Anyone with a known allergy to cinnamal or cinnamaldehyde in fragrances should check toothpastes, gums, and cosmetics as well as supplements. MSKCC records occupational allergy to cinnamal in a baker and allergic dermatitis from cinnamon oil in vaginal suppositories, showing that sensitisation can follow skin and mucosal contact as well as eating. A previous reaction to cinnamon gum, toothpaste, or cosmetics is a reason to avoid medicinal doses and cinnamon oil altogether.
Pregnancy, breastfeeding, and children: EMA does not recommend medicinal cinnamon in pregnancy or breastfeeding because safety has not been established, and does not recommend it under 18. NCCIH notes that amounts in food appear safe in pregnancy, but that Ceylon cinnamon in larger amounts during pregnancy is considered unsafe, and that little is known about larger amounts while breastfeeding. Children reach the coumarin limit at much smaller amounts of cassia than adults: BfR calculates about 0.5 g a day for a 15 kg child.
Liver disease and alcohol: NCCIH notes that prolonged use of cassia could be an issue for people sensitive to coumarin, such as those with liver disease. EMA’s assessment advises avoiding cinnamon oil by mouth in liver conditions, in alcoholism, and with paracetamol, and its overall conclusion adds fever of unknown origin and stomach or duodenal ulcers to the situations in which cinnamon medicines should not be used.
Diabetes and asthma: people with diabetes should not use cinnamon in place of prescribed treatment, and should monitor their blood sugar and tell their care team if they add a supplement. Anyone with asthma is at particular risk from inhaled cinnamon powder (Bosmia and Leon). Sudden choking, breathing difficulty, or chest pain after swallowing or inhaling cinnamon needs urgent medical attention.
08 Caution
Drug and herb interactions
Diabetes and liver-related medicines are the main concerns. MSKCC notes that cinnamon may lower blood glucose, so in theory it could add to the effect of diabetes medicines, and that in animal studies it raised the bioavailability of pioglitazone. Laboratory studies suggest cinnamon inhibits the liver enzymes CYP2C9, CYP3A4, CYP2A6, and CYP2D, which process many drugs, although clinical relevance is unknown. NCCIH notes theoretical interactions with an anticancer medicine and with nicotine; the study MSKCC cites examined cinnamaldehyde’s inactivation of CYP2A6 and estimated interactions with nicotine and the breast cancer drug letrozole. Hepatitis has been reported when cinnamon was taken with a statin (MSKCC; EMA).
EMA’s monograph reports no interactions for Ceylon cinnamon in medicinal doses, but its assessment report adds two cautions. Cassia bark (2 g in 100 ml) slowed the dissolution of tetracycline capsules in the laboratory, with only 20% dissolved in 30 minutes compared with 97% in water, so tetracyclines should not be taken with cinnamon doses of 1–2 g. And because cinnamaldehyde depletes glutathione, cinnamon oil should not be taken by mouth with paracetamol. MSKCC adds that cinnamon may theoretically increase prothrombin time, so people taking anticoagulants should tell their prescriber before using supplements.
09 Questions
Frequently Asked Questions
Ceylon or “true” cinnamon is Cinnamomum verum, grown mainly in Sri Lanka. Cassia covers several related species, including C. cassia and Indonesian C. burmannii, and is the most common cinnamon in North America. Ceylon sticks look like a cut cigar with many thin layers; cassia sticks are one thick rolled layer. The key difference for health is that cassia can contain much more coumarin.
Food amounts are likely safe for most people. The concern is coumarin in cassia: BfR calculates that a 60 kg adult reaches the tolerable daily intake with about 2 g of cassia a day, and a small child with about 0.5 g. Exceeding that briefly is not a risk, but if you use cinnamon heavily every day, BfR advises choosing Ceylon cinnamon.
Possibly a little, but not convincingly. Some meta-analyses find lower fasting glucose, but no clear effect on HbA1c, the measure of longer-term control, and a Cochrane review found insufficient evidence to recommend it. Most trials used cassia. Cinnamon should never replace diabetes medicines, and if you add a supplement, monitor your blood sugar and tell your care team.
Coumarin, found mainly in cassia, has caused liver damage in a small group of sensitive people when given as a medicine, usually reversible. BfR reports no described cases from eating cinnamon, but high-dose cassia supplements are a different matter, and a case of hepatitis has been reported with cinnamon taken alongside a statin. If you have liver disease, avoid cassia supplements and talk to your doctor before taking any herbal product marketed for the liver, including milk thistle.
The EU accepts Ceylon cinnamon tea as a traditional remedy for mild cramping, bloating, and flatulence, and for mild diarrhoea, based on long use rather than trials. Other traditional digestive herbs include ginger and peppermint, which has stronger trial evidence for irritable bowel syndrome. See a doctor if symptoms last more than two weeks, or diarrhoea more than two days.
Dry cinnamon dries out the mouth, so a spoonful is very hard to swallow and makes people cough. The powder can be inhaled into the lungs, where its fibres do not dissolve. US poison centre calls about the dare among teenagers rose from 51 in 2011 to 222 in 2012, some needed medical attention, and serious cases include collapsed lung segments. People with asthma are at particular risk. Never try it.
Yes. Cinnamaldehyde is a recognised contact allergen. Reactions include mouth sores and swollen gums from cinnamon gum or toothpaste, skin rashes from cinnamon oil or cosmetics, and rarely hives or asthma. EMA also advises people allergic to Peru balsam to avoid medicinal cinnamon. Stop using the product; in the cases EMA reviewed, reactions settled once the cinnamon was withdrawn.
Cinnamon in normal food amounts appears safe in pregnancy (NCCIH). Medicinal doses and supplements are another matter: EMA does not recommend medicinal cinnamon in pregnancy or breastfeeding, and NCCIH notes that larger amounts of Ceylon cinnamon in pregnancy are considered unsafe. Avoid concentrated cinnamon oil entirely.
10 References
Sources
These references support the history, clinical, and safety claims on this page. They are not an endorsement of any product.
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Cinnamon: Usefulness and Safety
National Center for Complementary and Integrative Health (NIH), 2024
Ceylon versus cassia; research does not clearly support any condition; coumarin; cinnamon challenge; pregnancy.
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Cinnamon
Memorial Sloan Kettering Cancer Center, About Herbs, 2021
Mixed diabetes data; allergy case reports; CYP, statin, pioglitazone, and prothrombin time cautions.
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Community herbal monograph on Cinnamomum verum J. S. Presl, cortex
European Medicines Agency (EMA/HMPC/246774/2009), 2011
Traditional use for mild spasmodic GI complaints and mild diarrhoea; 0.5–1 g tea up to four times daily; not under 18.
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Assessment report on Cinnamomum verum J. S. Presl, cortex and corticis aetheroleum
European Medicines Agency (EMA/HMPC/246773/2009), 2011
Botany, composition, history, contact allergy, oil toxicity, tetracycline and paracetamol cautions; no clinical efficacy data.
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Addendum to assessment report on Cinnamomum verum J. S. Presl, cortex
European Medicines Agency (EMA/HMPC/601683/2020), 2021
Periodic review: only three of 16 diabetes trials used C. verum; statin hepatitis case; Kampo coumarin study; no change.
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Coumarin in flavourings and other food ingredients with flavouring properties
European Food Safety Authority, EFSA Journal, 2008
Tolerable daily intake of 0.1 mg/kg body weight confirmed; threefold exceedance for one to two weeks not a concern.
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FAQ on coumarin in cinnamon and other foods
German Federal Institute for Risk Assessment (BfR), 2012
Cassia about 3,000 mg/kg coumarin; adult TDI reached with about 2 g cassia daily; EU food limits; telling sticks apart.
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Cassia cinnamon as a source of coumarin in cinnamon-flavored food and food supplements in the United States
Journal of Agricultural and Food Chemistry (PubMed 23627682), 2013
Wang et al.: only traces of coumarin in C. verum; substantial amounts in cassias; coumarin in all US supplements tested.
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Cinnamon for diabetes mellitus
Cochrane Database of Systematic Reviews (PubMed 22972104), 2012
Leach and Kumar: 10 RCTs, 577 participants; no significant effect on HbA1c; insufficient evidence.
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Cinnamon use in type 2 diabetes: an updated systematic review and meta-analysis
Annals of Family Medicine (PubMed 24019277), 2013
Allen et al.: 10 RCTs, 543 patients; fasting glucose −24.59 mg/dL; no significant HbA1c effect; high heterogeneity.
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Cinnamon improves glucose and lipids of people with type 2 diabetes
Diabetes Care (PubMed 14633804), 2003
Khan et al.: 60 patients, 1–6 g cassia daily for 40 days; subject of a 2025 expression of concern (PubMed 40834253).
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Cinnamon: a systematic review of adverse events
Clinical Nutrition (PubMed 29661513), 2019
Hajimonfarednejad et al.: GI upset and allergy most frequent, mostly self-limiting; safe as a spice.
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Ingesting and aspirating dry cinnamon by children and adolescents: the “cinnamon challenge”
Pediatrics (PubMed 23610205), 2013
Grant-Alfieri, Schaechter, and Lipshultz: warning to paediatricians about aspiration risk from the dare.
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Lung injury and the cinnamon challenge: college students should beware this Internet dare
Journal of Injury and Violence Research (PubMed 24121450), 2015
Bosmia and Leon: poison centre calls among teens rose from 51 in 2011 to 222 in 2012; lung risks.
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Noxious cold ion channel TRPA1 is activated by pungent compounds and bradykinin
Neuron (PubMed 15046718), 2004
Bandell et al.: cinnamaldehyde is the most specific TRPA1 activator among the pungent compounds tested.