Scientific Name(s): Cinnamomum verum J.S. Presl, Cinnamomum cassia Blume, Cinnamomum zeylanicum Nees, Cinnamomum loureirii Nees. Family: Laureaceae.

Common Name(s): Cinnamon , cinnamomon , ceylon cinnamon , Chinese cinnamon , Chinese cassia , Saigon cinnamon .


Cinnamon is used as a spice and aromatic. Traditionally, the bark or oil has been used to combat microorganisms, diarrhea, and other GI disorders, and dysmenorrhea, although there is limited data to support these uses. Evidence is lacking to support the use of cinnamon in the management of diabetes. Research has focused on anti-inflammatory, antioxidant, and antimicrobial activity.


Ground cinnamon is generally given at dosages of 1 to 1.5 g/day in studies of diabetes without reported adverse reactions.


Contraindicated in people who are allergic to cinnamon or Peru balsam. Further contraindications have not yet been identified.


Data are insufficient for adequate risk-to-benefit analysis. Generally recognized as safe when used in food.


None well documented.

Adverse Reactions

Heavy exposure may cause skin irritation and allergic reactions.


Information is lacking.


Cinnamon plants have oval-lanceolate, rough-textured leaves approximately 7 to 20 cm in length. The spice is derived from the brown bark, which forms quills with longitudinal striations. Cinnamon bark available in ground form as a spice. The plant is native to Sri Lanka, southeastern India, Indonesia, South America, and the West Indies. 1 , 2 , 3 , 4 , 5


Reports of cinnamon use date back to 2000 BC, when texts note the importation of cinnamon from China to Egypt. Cinnamon is also mentioned in the Bible, most often for its aromatic qualities. 5 Cinnamon is primarily used as a spice, taste enhancer, or aromatic. Historically, cinnamon has been used to treat GI upset and dysmenorrhea disorders of microcirculation, among other broad-ranging uses. 3 , 6 , 7 , 8 The essential oil derived from the plant has been used for its activity against various microorganisms and fungi. 3


The primary constituents of the essential oil are 65% to 80% cinnamaldehyde and lesser percentages of other phenols and terpenes, including eugenol, trans-cinnamic acid, hydroxycinnamaldehyde, o-methoxycinnamaldehyde, cinnamyl alcohol and its acetate, limonene, alpha-terpineol, tannins, mucilage, oligomeric procyanidins, and trace amounts of coumarin. 3 , 4

C. verum differs in composition from C. cassia in eugenol and coumarin content. Coumarin is only found in cassia (0.45%). 5 Varying sources of material and extraction techniques alter the chemical composition of the extracts, and may impact the intended medicinal and experimental effects. 6 , 9

Uses and Pharmacology

Animal data

In an experiment in which rats with induced diabetes were fed cinnamon via drinking water, no effect on blood glucose levels was shown. The researchers noted a significant decrease in platelet counts and a slight increase in hemoglobin in the rats. 10

Other researchers have isolated polyphenols from cinnamon that possess insulin-like activity and have demonstrated a dose-dependent increase in glucose utilization in animal muscle tissue. 8 , 11 , 12

Clinical data

A randomized clinical trial studying various dosages of cassia cinnamon powder (1, 3, or 6 g/day) over 40 days found a statistically and clinically significant improvement in blood glucose control among patients with type 2 diabetes. A reduction in cardiovascular risk factor biomarkers was also observed. 13 A second trial also found a significant reduction in fasting glucose levels at 3 g/day over 4 months, but no significant difference in the lipid profile. 14

Single bolus doses of cinnamon in healthy volunteers led to increased insulin sensitivity 15 and decreased postprandial blood glucose levels 16 in 2 small studies.

However, further clinical trials have been unable to replicate these positive findings in patients with type 1 or 2 diabetes at dosages of cinnamon 1 to 1.5 g/day. 17 , 18 , 19 A meta-analysis of 5 trials 20 and systematic reviews 21 , 22 have found no significant effect on glycated hemoglobin (A1C), fasting blood glucose, or lipid profiles. Evidence is lacking to support the clinical use of cinnamon in the management of diabetes. Variables suggested to account for the differences in trial outcomes include differing concurrent therapies, degree of control of the condition, and differences of populations studied. 18 , 20

Antioxidant effect

Cinnamon extracts appear to exhibit antioxidant action, with an ethanol extract showing more effectiveness than an aqueous extract. 23 The relative antioxidant action of cinnamon has been evaluated against other herbs and spices, and against alpha-tocopherol. 5 , 23 , 24 , 25 , 26

In an experiment to determine the wound healing action of an ethanol extract of cinnamon, researchers suggested the significant increase in wound healing was attributable to the antioxidant activity demonstrated. 27

Anti-inflammatory effect

A few laboratory experiments suggest anti-inflammatory action of certain chemical components in cinnamon. Cinnamaldehyde inhibits nitric oxide production implicated in the inflammatory disease process and also demonstrated inhibition of cyclooxygenase-2 catalyzed prostaglandin E2 biosynthesis. 28 , 29 , 30

Antimicrobial activity

Conflicting evidence exists for the action of cinnamon on Helicobacter pylori . In a small clinical study no effect on H. pylori was observed at dosages of extract 80 mg/day, but the study may have been underpowered. 5 , 31 , 32 A laboratory study using H. pylori isolates from hospital patients was able to demonstrate inhibition of all isolates by a methylene chloride cinnamon extract. 33

Cinnamon extracts have been shown to exert in vitro activity against some common human pathogens, 1 as well as fungicidal activity against plant pathogens. 34 , 35 In vitro inhibition of bacterial endotoxin has been demonstrated by an unidentified component in cinnamon bark. 36 The essential oils of cinnamon halted mycelial growth and aflatoxin synthesis in Aspergillus parasiticus at a concentration of only 0.1%. 37

Other uses

Angiogenesis inhibition, antiproliferative, and immunomodulatory effects have been demonstrated leading some researchers to suggest value in screening cinnamon for anticancer effects. 38 , 39 , 40 A stimulatory effect on human osteoblast cells has been demonstrated as well as some estrogenic activity. 41 A dose-dependent neuroprotective effect was demonstrated in rats with glutamate-induced neuronal cell death. 7


Ground cinnamon generally has been given at dosages of 1 to 1.5 g/day in studies of diabetes 13 , 17 , 18 , 19 and 80 mg/day in an ethanol extract in a study of activity against Helicobacter , without reported adverse reactions. 30


Data are insufficient for adequate risk-to-benefit analysis. Generally recognized as safe when used as food. Avoid dosages above those found in food because safety and efficacy are not proven. 42


None well documented. Cinnamon was reported to interfere with tetracycline dissolution rates in a laboratory experiment. 2 A theoretical potentiation of antidiabetic agents exists. 5 , 22

Adverse Reactions

Cinnamon has been given Generally Recognized As Safe (GRAS) status by the FDA. 5 At dosages of up to 6 g/day, no significant adverse reactions have been reported. 13 , 17 , 18 , 19 Human consumption of large quantities of cinnamon bark or moderate quantities of cinnamon oil has been shown to increase heart rate, intestinal movement, breathing, and perspiration via a chemical stimulation of the vasomotor center. This state of accelerated body function is followed by a period of centralized sedation that includes sleepiness or depression. 3

Contact dermatitis has been reported after single exposure and repeated use of cinnamon-containing preparations. 43 , 44 , 45 An acute exacerbation of rosacea has been reported consequent to consumption of cinnamon oil pills. 21

Oral mucosal lesions have been reported, commonly associated with cinnamon-flavored chewing gum and candies, 5 , 46 , 47 and exposure to cinnamon oil has been cited as a risk factor for oral cancers. 48 , 49 , 50


Information is lacking. Teratogenicity in chick embryos has been reported in one study; in another, no evidence of teratogenicity in rats given a methanol extract of cinnamon was demonstrated. 1 A case report describes vomiting, diarrhea, and loss of consciousness in a child who consumed cinnamon oil 60 mL. 5


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