Most cinnamon sold in shops is cassia, not true cinnamon. True cinnamon, Cinnamomum verum, also called Ceylon cinnamon, is native to Sri Lanka. Cassia comes from related species, and China, Vietnam and Indonesia lead world production. Both are the dried inner bark of a tree, only about 0.5 mm thick, which curls into rolls called quills as it dries.
The difference matters for one compound, coumarin, which can harm the liver in large amounts. Germany’s Federal Institute for Risk Assessment (BfR) puts cassia at about 3,000 mg of coumarin per kilogram on average. Measured highs reach 10,000 mg/kg, while Ceylon cinnamon holds only traces. A cinnamon jar that says only “cinnamon” is often cassia.
As a food, cinnamon adds very little. One teaspoon (2.6 g) has 6 calories, 1.4 g of fiber and 0.45 mg of manganese. That manganese is 20% of the Daily Value, the FDA’s daily target.
Most research is not about that teaspoon. Blood sugar trials mostly used 1 to 6 g a day in capsules, up to about 2¼ teaspoons. In 2006 the BfR warned that cassia capsules at such doses can push coumarin intake past the EU limit.
Health benefits of cinnamon
The top findings from 28 studies, strongest evidence first
What the stars mean
- Strong. Several randomized trials, pooled in a meta-analysis, point the same way, or regulators (FDA or EFSA) have approved the claim.
- Moderate. Good randomized trials support it, but there are fewer of them, or their results vary.
- Limited. Small, short or single trials, or mixed results. Promising, but it needs confirmation.
Population and lab studies get no stars: they show a link or a mechanism, not proof.
How we rate evidence →- ★★Mixed results for blood sugar in diabetesPooled analyses disagree. One found cinnamon lowered fasting glucose by 0.545 mmol/L across 16 trials, while a Cochrane review of 10 trials called the evidence inconclusive.
- ★★Lower blood pressureAcross 9 trials in 641 adults, cinnamon supplements lowered the top number by about 6 points (6.23 mm Hg systolic). The bottom number fell 3.93 mm Hg.
- ★★Lower triglycerides and total cholesterolAcross 13 trials, cinnamon supplements lowered triglycerides by 0.27 mmol/L and total cholesterol by 0.36 mmol/L. LDL and HDL cholesterol did not clearly change.
- ★★A little lower body weight with supplementsAcross 12 trials in 786 adults, cinnamon supplements lowered body weight by 1.02 kg. Waist size fell 2.40 cm.
- ★Smaller blood sugar rise after rice pudding14 healthy adults ate 300 g of rice pudding with or without 6 g of cinnamon (about 2¼ teaspoons, a lot for one dish). Blood sugar rose less with the cinnamon.
All 28 studies, strongest evidence first
Cochrane review: not enough evidence that cinnamon helps in diabetes
This review pooled 10 randomized trials (577 people with type 1 or type 2 diabetes) of oral cinnamon, mostly cassia. The average dose was 2 g a day (about three quarters of a teaspoon) for 4 to 16 weeks. Fasting glucose results were inconclusive, and HbA1c, insulin and after-meal glucose did not differ from control. Nearly all trials had a high or unclear risk of bias.
Cinnamon lowered fasting glucose by about 25 mg/dL
This meta-analysis pooled 10 randomized trials in 543 people with type 2 diabetes. They used 120 mg to 6 g of cinnamon a day (up to about 2¼ teaspoons) for 4 to 18 weeks. Total cholesterol, LDL and triglycerides fell and HDL rose, but HbA1c did not clearly change. Results differed widely between trials, so the best dose and duration are unclear.
In 16 trials, cinnamon lowered fasting glucose by 0.545 mmol/L
This meta-analysis pooled 16 randomized trials of cinnamon against placebo in type 2 diabetes and prediabetes. The drop equals about 10 mg/dL, and insulin resistance (HOMA-IR) also fell. HbA1c and blood fats did not change. Results differed a lot between trials, and the authors ask for standardized cinnamon products in future work.
Updated meta-analysis: supplements lowered fasting blood sugar and HbA1c
This updated meta-analysis pooled 24 randomized trials of cinnamon supplements in type 2 diabetes. The standardized differences (a measure of effect size) were -1.32 for fasting blood sugar and -0.67 for HbA1c. Insulin did not clearly change. The authors suggest cinnamon might help as an add-on to usual care, a firmer conclusion than the Cochrane review above.
Dose-response analysis: no change in fasting glucose or HbA1c overall
This dose-response meta-analysis pooled randomized trials of cinnamon in type 2 diabetes. Triglycerides and LDL fell and HDL rose. Only a subgroup of trials using 1,200 mg a day or less (under half a teaspoon) showed lower glucose. So the blood sugar result depends on how the trials are grouped.
23 studies: no difference in HbA1c, LDL or HDL
This pooled analysis covered 23 studies (1,070 people) of cinnamon consumption, comparing people who took it with those who did not. The authors call the studies heterogeneous (very different from each other) and generally of very poor quality. They ask for long-term randomized trials with a stronger design.
Cinnamon bark capsules improved blood sugar, HbA1c and body fat
In this triple-blind, placebo-controlled trial, 140 people with type 2 diabetes took 500 mg of cinnamon bark powder capsules twice a day for 3 months. Fasting and after-meal glucose, insulin resistance, BMI and body fat all improved, though triglycerides did not. Changes were larger in people with a BMI of 27 or more. The abstract does not name the cinnamon species.
13 trials: supplements lowered triglycerides by 0.27 mmol/L
This meta-analysis pooled 13 randomized trials (750 people) of cinnamon supplements. Total cholesterol fell 0.36 mmol/L. LDL and HDL cholesterol did not clearly change, although HDL rose when one study was left out.
Pooled trials: cinnamon lowered systolic blood pressure by 6.23 mmHg
This meta-analysis pooled 9 randomized trials of cinnamon supplements in 641 adults. Diastolic pressure fell 3.93 mmHg. Systolic pressure fell more in trials that used 2 g a day or less (about three quarters of a teaspoon). It also fell more in trials of 12 weeks or longer, or in people under 50.
Pooled trials: cinnamon lowered body weight by 1.02 kg
This meta-analysis pooled 12 randomized trials of cinnamon supplements in 786 adults. Waist size fell 2.40 cm, BMI 0.51 and body fat 1.02%. Fat mass fell only at 2 g a day or more (about three quarters of a teaspoon) taken for 12 weeks or longer.
Cinnamon in rice pudding lowered the blood sugar rise after eating
In this crossover trial, 14 healthy adults ate 300 g of rice pudding with or without 6 g of cinnamon. That is about 2¼ teaspoons, a lot for one dish. The cinnamon also slowed stomach emptying, but fullness did not change. It tested one meal in people without diabetes.
Cinnamon in cereal lowered blood sugar from 15 to 60 minutes
This crossover study included 30 adults aged 18 to 30, half of them with obesity. They ate farina cereal with 50 g of carbohydrate, plain or with 6 g of ground cinnamon (about 2¼ teaspoons). Blood sugar was higher with cinnamon at 2 hours, but the 2-hour glucose total was lower. The result did not differ between normal-weight and obese adults.
3 g of cinnamon in rice pudding lowered the insulin response
In this crossover trial, 15 healthy adults ate rice pudding with 1 or 3 g of cinnamon (3 g is a little over a teaspoon). Neither dose changed blood sugar. The hormone GLP-1 rose with 3 g, while stomach emptying, fullness and ghrelin did not change.
Cinnamon tea from C. burmannii slightly lowered blood sugar
In this randomized trial, adults without diabetes had a glucose tolerance test (a sugary drink) with or without cinnamon tea. Blood sugar rose slightly less with the tea, and peak glucose was also lower. The abstract does not state how many people took part or how much cinnamon the tea held.
Cinnamon spice daily lowered average 24-hour blood glucose in prediabetes
In this randomized, double-blind crossover trial, 18 adults with obesity and prediabetes took 4 g of cinnamon spice a day for 4 weeks. That is about 1½ teaspoons, and glucose was tracked with continuous monitors. Glucose peaks were lower (a rise of 9.56 against 11.73 mg/dL on placebo) and triglycerides fell. Digestive symptoms did not differ, and the abstract does not name the cinnamon species.
Cinnamon capsules lowered HbA1c by 0.83%, usual care alone 0.37%
This randomized trial at US military clinics included 109 people with type 2 diabetes and an HbA1c above 7%. They took 1 g of cinnamon capsules a day for 90 days, about two fifths of a teaspoon. The comparison group received usual care with no placebo, and both groups improved.
Cassia cinnamon did not improve insulin sensitivity or glucose tolerance
In this placebo-controlled trial, 25 postmenopausal women with type 2 diabetes took 1.5 g of cassia a day for 6 weeks. That is a bit over half a teaspoon. Blood fats did not change either. The authors asked for more research before any health claims are made.
Daily cinnamon lowered HbA1c from 8.22% to 7.86% against placebo
In this placebo-controlled, double-blind trial, 58 UK adults with poorly controlled type 2 diabetes took 2 g of cinnamon a day for 12 weeks. They also took diabetes drugs, and HbA1c rose on placebo. Blood pressure also fell (systolic 132.6 to 129.2 mmHg), but the fall in fasting glucose did not differ from placebo. The 2 g dose is about three quarters of a teaspoon.
6 g of Ceylon cinnamon did not change blood sugar or insulin
In this crossover trial, 10 people with impaired glucose tolerance took Ceylon cinnamon capsules and had a glucose drink. The dose, 6 g, is about 2¼ teaspoons. The team chose Ceylon cinnamon because it has far less coumarin than cassia. It is a very small study of a single test.
Cinnamon capsules lowered fasting glucose by 18 to 29% in diabetes
In this capsule trial, 60 people with type 2 diabetes took 1, 3 or 6 g of cinnamon a day for 40 days. These doses range from about two fifths of a teaspoon to 2¼ teaspoons. It also reported lower triglycerides and cholesterol, with no change in the placebo groups. PubMed lists a 2025 expression of concern from the journal about this paper, so treat it with caution.
Cinnamon capsules eased period pain more than placebo
In this randomized, double-blind trial, women took 1,000 mg cinnamon capsules in the first 72 hours of their period, over two cycles. Pain was rated on a visual scale, and it fell in both groups, but more with cinnamon. The abstract does not give the number of participants or the cinnamon species.
Pooled trials: cinnamon did not change liver enzymes overall
This meta-analysis pooled seven randomized trials (256 people) measuring the liver enzymes ALT, AST and ALP. In people with type 2 diabetes, ALT was 4.01 U/L lower. The authors call for better trials, especially in people whose liver tests are already abnormal.
Cinnamon extract lowered fasting glucose by 10.3%, against 3.4% on placebo
In this double-blind trial, 79 adults with type 2 diabetes took a purified water extract of cinnamon for 4 months. It was equal to 3 g of powder a day, not the spice itself. HbA1c and blood fats did not change, and no adverse effects were seen. People with higher starting glucose seemed to gain more.
Ceylon cinnamon extract lowered fasting glucose and HbA1c from baseline
In this double-blind, placebo-controlled trial, 210 people with type 2 diabetes took 250 or 500 mg of Ceylon cinnamon extract for 4 months. Of them, 186 finished. The abstract reports declines against starting values rather than placebo-adjusted numbers, and the authors report holding a patent.
Eating cinnamon was not linked to a lower risk of dying
The Golestan Cohort Study followed 44,398 Iranian adults for 11 years. It compared people who ever ate cinnamon with those who never did, using a food frequency questionnaire. Turmeric, pepper and saffron showed links with lower mortality, but cinnamon did not. Observational data cannot show cause.
Cinnamaldehyde switched on receptors linked to insulin sensitivity in lab cells
This cell study used human kidney-derived cells and fat cells. Cinnamaldehyde, a compound from cinnamon, switched on the receptors PPARδ, PPARγ and RXR. It tested the isolated compound, not cinnamon as eaten, so it only suggests a mechanism.
Cinnamaldehyde activated heat-producing genes in lab-grown fat cells
This cell study tested the isolated compound on mouse fat cells and fat cells from multiple human donors, grown in the lab. It does not show that eating cinnamon raises calorie burning in people.
Cinnamaldehyde lengthened the lifespan of roundworms
This study fed the isolated compound to C. elegans worms, with supporting work in human cells. The compound acted on growth and recycling pathways in the human cells. It is not known whether eating cinnamon does the same in people.
Who should be careful with cinnamon
Most people can eat cinnamon freely as a spice. Take a little care if one of these applies:
- Daily cassia, especially for small children. Cassia contains coumarin. The European Food Safety Authority (EFSA) set a tolerable daily intake of 0.1 mg per kilogram of body weight. That is the amount considered safe to eat every day for life. The BfR uses an average of 3,000 mg/kg in cassia. It estimates the limit is reached with about 0.5 g a day (about one fifth of a teaspoon) for a 15 kg child. For a 60 kg adult it is about 2 g (about three quarters of a teaspoon). A small child eating rice pudding with 0.5 g twice a week would reach 29% of the limit. A level teaspoon (2.6 g) every day passes it for both. Ceylon cinnamon has only traces of coumarin.
- Cinnamon capsules and supplements. The BfR concluded in 2006 that capsules of cassia powder can push coumarin intake over the limit. The US National Center for Complementary and Integrative Health says long-term cassia use could be a concern for sensitive people, including those with liver disease. Most trials of capsules lasted months, not years.
- Allergy or a sore mouth. A systematic review of trials, case reports and national reports found stomach problems and allergic reactions were the most frequent problems with cinnamon. Most cleared by themselves. It judged cinnamon safe as a spice, with the larger problems tied to bigger medicinal doses or longer use.
How to choose, store and eat cinnamon
- Ceylon (true) cinnamon: the low-coumarin choice. A study of product labels reported under 0.01 mg of coumarin per gram, against 2.23 mg per gram in cassia.
- Cassia: the kind most often sold. At the BfR’s average of 3,000 mg/kg, a level teaspoon (2.6 g) a day passes the limit for a 60 kg adult. So treat it as a sprinkle, not a daily spoonful.
- In porridge, rice pudding or tea: mixing it into food does not lock the coumarin away. In 24 volunteers, absorption from cinnamon in rice pudding was 54.7%, against 62.8% for pure coumarin.
Read the label, since plain “cinnamon” is often cassia. One study of 276 product labels found Ceylon’s low coumarin rarely printed on them. Look for “Ceylon” or Cinnamomum verum if you want the low-coumarin kind. Keep cinnamon in an airtight container in a cool, dark place, because the flavor of spices weakens over time.
Sources
- Cinnamon, ground (FDC 171320). USDA FoodData Central.
- FAQ on coumarin in cinnamon and other foods. Federal Institute for Risk Assessment (BfR). 2012.
- High daily intakes of cinnamon: health risk cannot be ruled out. BfR Health Assessment No. 044/2006. 2006.
- Opinion of the Scientific Panel on food additives, flavourings, processing aids and materials in contact with food (AFC) related to coumarin. EFSA Journal. 2004.
- Cinnamon. National Center for Complementary and Integrative Health, NIH. 2024.
- Hajimonfarednejad M, Ostovar M, Raee MJ, et al. Cinnamon: a systematic review of adverse events. Clin Nutr. 2019.
- Abraham K, Pfister M, Wöhrlin F, Lampen A. Relative bioavailability of coumarin from cinnamon and cinnamon-containing foods compared to isolated coumarin: a four-way crossover study in human volunteers. Mol Nutr Food Res. 2011.
- De Silva DAM, Jeewanthi RKC, Rajapaksha RHN, et al. Clean vs dirty labels: transparency and authenticity of the labels of Ceylon cinnamon. PLoS One. 2021.
- Cinnamon. Wikipedia.
- Spices, do they expire? Texas A&M AgriLife Extension. 2019.
History of cinnamon
Cinnamon is one of the world’s oldest spices. It was imported into Egypt as early as 2000 BC and used to embalm mummies. From the Ptolemaic period, it also went into recipes for kyphi, an aromatic that was burned. Some reports that it came from China confused it with cassia.
Where it came from stayed a secret for centuries. The Greek writer Herodotus said cinnamon and cassia grew in Arabia and were guarded by winged serpents. The Roman author Pliny the Elder called a related tale a traders’ fiction meant to raise prices.
Pliny reported that a Roman pound of cassia or cinnamon cost up to 1,500 denarii. Nero is said to have burned a year’s supply at the funeral of Poppaea Sabina in AD 65. Arabian traders controlled the European trade through limited supplies from a country they did not reveal.
Europeans were still vague in the 13th century. Joinville, who went to Egypt with King Louis IX in 1248, repeated a story that cinnamon was fished from the source of the Nile. Sri Lanka is first named around 1270, in the work of al-Qazwini.
Venetian traders then dominated distribution from Alexandria. Disruption of that trade was one of the factors that pushed Europeans to look for other routes to Asia.
Control of Sri Lankan cinnamon then passed between European powers. The Portuguese held it in the 1500s. The Dutch set up a trading post in 1638 and controlled the processing sites by 1640. They expelled the Portuguese by 1658 and later began growing their own trees.
The British took Ceylon from the Dutch in 1796. A 1978 review noted that the way cinnamon oil is made changed little from the methods of the early Dutch settlers.
The words carry some of this history. The word “cassia” comes from a Hebrew word meaning to strip off bark. Several European names for cinnamon come from the Latin cannella, a small tube, for the way the bark curls as it dries.
Today most cinnamon is cassia. In 2023 world production was 238,403 tonnes, and China, Vietnam, Indonesia and Sri Lanka made 98% of it, with Sri Lanka at 22,410 tonnes. True cinnamon is native to Sri Lanka, which still produces 80 to 90% of the world’s supply of it.
Sources
- Cinnamon. Wikipedia.
- Cinnamomum verum. Wikipedia.
- Wijesekera RO. Historical overview of the cinnamon industry. CRC Crit Rev Food Sci Nutr. 1978.
- De Silva DAM, Jeewanthi RKC, Rajapaksha RHN, et al. Clean vs dirty labels: transparency and authenticity of the labels of Ceylon cinnamon. PLoS One. 2021.
Frequently asked questions about cinnamon
Is cinnamon good for you?
In the small amounts people eat, it is mostly a flavoring with a few nutrients. A teaspoon (2.6 g) has 6 calories, 1.4 g of fiber and 20% of the Daily Value for manganese. The health research uses capsules and extracts of 1 to 6 g, and none of it reaches strong evidence. With cassia, the main concern is coumarin if you eat larger amounts every day.
Does cinnamon lower blood sugar?
Possibly a little, but the evidence is mixed. A Cochrane review of 10 trials found insufficient evidence, and meta-analyses of 16 and 24 trials found lower fasting glucose. A 23-study analysis and a dose-response analysis found no change in HbA1c overall. Most trials used capsules of 1 to 6 g, and the few that put cinnamon in a meal measured one meal at a time. If you have diabetes, ask your care team before taking cinnamon capsules, and do not use them in place of medicine.
How much cinnamon can you eat a day?
No study sets an ideal amount, and for cassia the limit comes from coumarin, not from benefit. The BfR estimates the tolerable daily intake is reached at about 2 g of cassia (three quarters of a teaspoon) for a 60 kg adult. Ceylon cinnamon has only traces of coumarin, and trials used 1 to 6 g a day, up to about 2¼ teaspoons, mostly as capsules. If you are not sure which type you have, treat it as cassia.
What is the difference between Ceylon and cassia cinnamon?
Mainly the coumarin: Ceylon cinnamon (Cinnamomum verum) has only traces, while cassia averages about 3,000 mg per kilogram. A label study measured under 0.01 mg/g in Ceylon against 2.23 mg/g in cassia. Ceylon comes from Sri Lanka, while most cinnamon sold is cassia. Ceylon has been tested less: 6 g capsules did not change blood sugar in 10 people, while an extract lowered glucose from baseline in 210.
Is cinnamon safe for children?
In small amounts yes, but cassia adds up quickly for small children. The BfR estimates a 15 kg child reaches the coumarin limit with about 0.5 g of cassia a day, about one fifth of a teaspoon. A small child eating rice pudding with 0.5 g of cassia twice a week would reach 29% of the limit. Ceylon cinnamon, with only traces of coumarin, leaves much more room.
Is cinnamon good for weight loss?
The evidence is weak and the effect small. A meta-analysis of 12 trials found cinnamon supplements lowered body weight by 1.02 kg and waist size by 2.40 cm. Fat mass fell only at 2 g a day or more for 12 weeks or longer. No study here tested cinnamon sprinkled on food for weight, and a teaspoon adds just 6 calories.
Does cinnamon lower cholesterol or blood pressure?
Probably only slightly, and the cholesterol results are mixed. A meta-analysis of 13 trials found lower triglycerides (0.27 mmol/L) and total cholesterol (0.36 mmol/L), but no clear change in LDL or HDL. Another, of 9 trials, found systolic blood pressure 6.23 mmHg lower. Both pooled supplements, not food, and a 23-study analysis found no difference in LDL or HDL and called the studies very poor in quality.
How many calories are in a teaspoon of cinnamon?
About 6 calories. A teaspoon (2.6 g) also has 1.4 g of fiber, 0.7 g of net carbs and 0.1 g of protein. It holds 0.45 mg of manganese, which is 20% of the Daily Value, and 26 mg of calcium, which is 2%.