Purported Benefits, Side Effects & More


Purported Benefits, Side Effects & More

Common Names

  • Cassia

For Patients & Caregivers

Tell your healthcare providers about any dietary supplements you’re taking, such as herbs, vitamins, minerals, and natural or home remedies. This will help them manage your care and keep you safe.

What is it?

Evidence suggests possible benefits with cinnamon for lowering blood sugar and blood fat levels, but additional studies are needed to confirm this.

Cinnamon refers to several plants native to Southeast Asia. The bark, rich in essential oil, is used as a flavoring agent and as a spice. Cinnamon has a long history of use as an herbal medicine.

Lab studies suggest that cinnamon has antibacterial, anti-inflammatory, and antioxidant properties. Studies in humans suggest it may help lower blood sugar, total cholesterol and triglyceride levels, and reduce risks for cardiovascular disease, stroke and diabetes. However, additional studies are needed to confirm these effects.

What are the potential uses and benefits?
  • Diabetes

    Results have been mixed for various diabetes-related markers. A few meta-analyses suggest improvements in blood sugar and blood fat levels, but larger well-designed trials are needed to confirm these effects.
  • Inflammation

    Lab studies suggest that cinnamon can reduce inflammation, but human data are lacking.
  • Arthritis

    Cinnamon is used in traditional medicine for arthritis, but there is no scientific evidence to support this claim.
What are the side effects?
  • GI upset: stomachache, heartburn, nausea, constipation, diarrhea
  • Allergic reactions

Case reports

  • Mouth sores: Associated with using oral cinnamon products like herbal toothpaste and gum.
  • Occupational allergy: With cinnamon due to exposure to its compounds.
  • Skin irritations: In one case with use of vaginal suppositories containing cinnamon oil, and in another case after consuming herbal tea that had large amounts of cinnamon.
What else do I need to know?

Patient Warnings:

  • Some cinnamon products contain high levels of coumarin, a natural constituent, that can cause liver damage.

Do Not Take if:

  • CYP450 2A6, 2C9, 2D, and 3A4 substrate drugs: Lab studies suggest cinnamon may increase the risk of side effects of these drugs. Clinical relevance has yet to be determined.
  • Statins: When taken along with statins, cinnamon has been reported to cause hepatitis.
  • Pioglitazone (an antidiabetic drug): Animal studies show that when used together, cinnamon can increase the bioavailability of pioglitzone.

For Healthcare Professionals

Scientific Name
Cinnamomum zeylanicum, Cinnamomum aromaticum, Cinnamomum loureiroi, Cinnamomum burmannii
Clinical Summary

Cinnamon refers to several plants that belong to the genus Cinnamomum, native to Southeast Asia. The bark, rich in essential oil, is used as a flavoring agent and as a spice. Medicinal uses include appetite stimulation, and treatment of arthritis, inflammation, and dyspepsia. In traditional Chinese medicine, cinnamon is used along with other herbs in decoctions to treat colds.

In vitro studies suggest that cinnamon has antioxidant (1) (2), anti-inflammatory (3), immunomodulatory (4) (5), antimicrobial (6), antitumor (7) , and antiestrogenic (26) properties.

Studies in humans have also been conducted. In clinical trials of cinnamon for type 2 diabetes, results are conflicting (8) (9) (10) (11) (37) (46) (47). Various meta-analyses and a review suggest some improvements in glycemic control with cinnamon and its extracts (12) (36) (48), but studies had high heterogeneity and larger well-designed trials are needed. Other meta-analyses suggest cinnamon supplementation may reduce blood triglycerides, total cholesterol concentrations (38), and C-reactive protein levels (49), but again well-designed studies are needed to confirm these effects.

Other preliminary data suggest cinnamon extracts may decrease insulin resistance in women with polycystic ovary syndrome (39); improve parameters of metabolic syndrome (40); and reduce dental plaque and gingivitis (32). Studies involving topical use of a cinnamon ointment suggest it can relieve perineal pain and improve healing of episiotomy incisions in postpartum women (33).

In a safety study of patients with prediabetes, a water-soluble cinnamon extract did not appear to affect electrocardiographic measures (50). However, certain cinnamon products are high in coumarin (18) (17), which can cause hepatotoxicity (19) and interact with other prescription drugs (20).

Food Sources

Cinnamon bark

Purported Uses and Benefits
  • Diabetes
  • Inflammation
  • Arthritis
Mechanism of Action

Hydroxycinnamaldehyde, a compound present in cinnamon, exerts anti-inflammatory effects by inhibiting NO production via nuclear factor (NF)-kappaB (3). Cinnamon also inhibits hepatic HMG-CoA reductase activity (24) and reduces blood lipid levels in animals and humans (10). In another study, methylhydroxychalcone polymer isolated from cinnamon was shown to mimic insulin by activating the insulin receptors (23).

Cinnamon extract binds to estrogen-receptor beta and has a direct stimulatory effect on bone formation (25). The n-hexane extract of cinnamon has antiestrogenic activity (26). In other studies, increased proapoptotic activity with cinnamon extract was attributed to NF-kappaB and AP1 inhibition (7), while antiangiogenic effects occurred via VEGF inhibition (22).

Adverse Reactions

Most common: Gastrointestinal upset and allergic reactions that are self-limiting in many cases (42).

Case reports

  • Plasma cell gingivitis and stomatitis: Following use of oral cinnamon products including toothpaste and chewing gum (13) (15) (16) (27) (34).
  • Occupational allergy: In a baker due to exposure to cinnamal, a compound in cinnamon (28).
  • Allergic contact dermatits: In an 18-year-old following use of vaginal suppositories containing cinnamon oil (29).
  • Systemic dermatitis: In a 26-year old after drinking several cups of herbal tea containing large amounts of cinnamon (41).
Herb-Drug Interactions
  • CYP450 substrates: Preclinical studies suggest cinnamon inhibits CYP 2C9, 3A4 (31), 2A6 (43), and 2D (44), and may interfere with the actions of drugs metabolized by these enzymes (31). Clinical relevance has yet to be determined.
  • Statins: When taken along with statins, cinnamon has been reported to cause hepatitis (35).
  • Pioglitazone: Cinnamon enhanced bioavailability upon concomitant use in preclinical studies (45).
Herb Lab Interactions
  • Cinnamon may lower blood glucose and cholesterol levels, but evidence is mixed (8) (10).
  • Theoretically, cinnamon may increase prothrombin time (30).
Dosage (OneMSK Only)
  1. Kim SH, Hyun SH, Choung SY. Antioxidative effects of Cinnamomi cassiae and Rhodiola rosea extracts in liver of diabetic mice. Biofactors. 2006;26(3):209-219.
  2. Lin CC, Wu SJ, Chang CH, et al. Antioxidant activity of Cinnamomum cassia. Phytother Res. Aug 2003;17(7):726-730.
  3. Lee SH, Lee SY, Son DJ, et al. Inhibitory effect of 2’-hydroxycinnamaldehyde on nitric oxide production through inhibition of NF-kappa B activation in RAW 264.7 cells. Biochem Pharmacol. Mar 1 2005;69(5):791-799.
  4. Reddy AM, Seo JH, Ryu SY, et al. Cinnamaldehyde and 2-methoxycinnamaldehyde as NF-kappaB inhibitors from Cinnamomum cassia. Planta Med. Sep 2004;70(9):823-827.
  5. Koh WS, Yoon SY, Kwon BM, et al. Cinnamaldehyde inhibits lymphocyte proliferation and modulates T-cell differentiation. Int J Immunopharmacol. Nov 1998;20(11):643-660.
  6. Shahverdi AR, Monsef-Esfahani HR, Tavasoli F, et al. Trans-cinnamaldehyde from Cinnamomum zeylanicum bark essential oil reduces the clindamycin resistance of Clostridium difficile in vitro. J Food Sci. Jan 2007;72(1):S055-058.
  7. Kwon HK, Hwang JS, So JS, et al. Cinnamon extract induces tumor cell death through inhibition of NFkappaB and AP1. BMC Cancer. 2010;10:392.
  8. Blevins SM, Leyva MJ, Brown J, et al. Effect of cinnamon on glucose and lipid levels in non insulin-dependent type 2 diabetes. Diabetes Care. Sep 2007;30(9):2236-2237.
  9. Khan A, Safdar M, Ali Khan MM, et al. Cinnamon improves glucose and lipids of people with type 2 diabetes. Diabetes Care. Dec 2003;26(12):3215-3218.
  10. Mang B, Wolters M, Schmitt B, et al. Effects of a cinnamon extract on plasma glucose, HbA, and serum lipids in diabetes mellitus type 2. Eur J Clin Invest. May 2006;36(5):340-344.
  11. Vanschoonbeek K, Thomassen BJ, Senden JM, et al. Cinnamon supplementation does not improve glycemic control in postmenopausal type 2 diabetes patients. J Nutr. Apr 2006;136(4):977-980.
  12. Davis PA, Yokoyama W. Cinnamon intake lowers fasting blood glucose: meta-analysis. J Med Food. Sep 2011;14(9):884-889.
  13. Anil S. Plasma cell gingivitis among herbal toothpaste users: a report of three cases. J Contemp Dent Pract. 2007;8(4):60-66.
  14. Endo H, Rees TD. Clinical features of cinnamon-induced contact stomatitis. Compend Contin Educ Dent. Jul 2006;27(7):403-409; quiz 410, 421.
  15. Endo H, Rees TD. Cinnamon products as a possible etiologic factor in orofacial granulomatosis. Med Oral Patol Oral Cir Bucal. Oct 2007;12(6):E440-444.
  16. Kind F, Scherer K, Bircher AJ. Allergic contact stomatitis to cinnamon in chewing gum mistaken as facial angioedema. Allergy. Feb 2010;65(2):276-277.
  17. Lungarini S, Aureli F, Coni E. Coumarin and cinnamaldehyde in cinnamon marketed in Italy: a natural chemical hazard? Food Addit Contam Part A Chem Anal Control Expo Risk Assess. Nov 2008;25(11):1297-1305.
  18. Woehrlin F, Fry H, Abraham K, et al. Quantification of flavoring constituents in cinnamon: high variation of coumarin in cassia bark from the German retail market and in authentic samples from indonesia. J Agric Food Chem. Oct 13 2010;58(19):10568-10575.
  19. Abraham K, Wohrlin F, Lindtner O, et al. Toxicology and risk assessment of coumarin: focus on human data. Mol Nutr Food Res. Feb 2010;54(2):228-239.
  20. Federal Institute for Risk Assessment. Selected Questions about coumarin in cinnamon and other foods. Accessed June 7, 2021.
  21. Dugoua JJ, Seely D, Perri D, et al. From type 2 diabetes to antioxidant activity: a systematic review of the safety and efficacy of common and cassia cinnamon bark. Can J Physiol Pharmacol. Sep 2007;85(9):837-847.
  22. Lu J, Zhang K, Nam S, et al. Novel angiogenesis inhibitory activity in cinnamon extract blocks VEGFR2 kinase and downstream signaling. Carcinogenesis. Mar 2010;31(3):481-488.
  23. Jarvill-Taylor KJ, Anderson RA, Graves DJ. A hydroxychalcone derived from cinnamon functions as a mimetic for insulin in 3T3-L1 adipocytes. J Am Coll Nutr. Aug 2001;20(4):327-336.
  24. Lee JS, Jeon SM, Park EM, et al. Cinnamate supplementation enhances hepatic lipid metabolism and antioxidant defense systems in high cholesterol-fed rats. J Med Food. Fall 2003;6(3):183-191.
  25. Lee KH, Choi EM. Stimulatory effects of extract prepared from the bark of Cinnamomum cassia blume on the function of osteoblastic MC3T3-E1 cells. Phytother Res. Nov 2006;20(11):952-960.
  26. Kim IG, Kang SC, Kim KC, et al. Screening of estrogenic and antiestrogenic activities from medicinal plants. Environ Toxicol Pharmacol. Jan 2008;25(1):75-82.
  27. Siqueira AS, Santos CC, Cristino MR, et al. Intraoral contact mucositis induced by cinnamon-flavored chewing gum—a case report. Quintessence Int. Oct 2009;40(9):719-721.
  28. Guarneri F. Occupational allergy to cinnamal in a baker. Contact Dermatitis. Nov 2010;63(5):294.
  29. Lauriola MM, De Bitonto A, Sena P. Allergic contact dermatitis due to cinnamon oil in galenic vaginal suppositories. Acta Derm Venereol. Mar 2010;90(2):187-188.
  30. Chase CK, McQueen CE. Cinnamon in diabetes mellitus. Am J Health Syst Pharm. May 15 2007;64(10):1033-1035.
  31. Kimura Y, Ito H, Hatano T. Effects of mace and nutmeg on human cytochrome P450 3A4 and 2C9 activity. Biol Pharm Bull. 2010;33(12):1977-82.
  32. Gupta D, Jain A. Effect of Cinnamon Extract and Chlorhexidine Gluconate (0.2%) on the Clinical Level of Dental Plaque and Gingival Health: A 4-Week, Triple-Blind Randomized Controlled Trial. J Int Acad Periodontol. 2015 Jul;17(3):91-8.
  33. Mohammadi A, Mohammad-Alizadeh-Charandabi S, Mirghafourvand M, Javadzadeh Y, Fardiazar Z, Effati-Daryani F. Effects of cinnamon on perineal pain and healing of episiotomy: a randomized placebo-controlled trial. J Integr Med. 2014 Jul;12(4):359-66.
  34. Calapai G, Miroddi M, Mannucci C, Minciullo P, Gangemi S. Oral adverse reactions due to cinnamon-flavoured chewing gums consumption. Oral Dis. 2014 Oct;20(7):637-43.
  35. Brancheau D, Patel B, Zughaib M. Do cinnamon supplements cause acute hepatitis? Am J Case Rep. 2015 Apr 29;16:250-4.
  36. Costello RB, Dwyer JT, Saldanha L, Bailey RL, Merkel J, Wambogo E. Do Cinnamon Supplements Have a Role in Glycemic Control in Type 2 Diabetes? A Narrative Review. J Acad Nutr Diet. 2016 Nov;116(11):1794-1802.
  37. Zare R, Nadjarzadeh A, Zarshenas MM, Shams M, Heydari M. Efficacy of cinnamon in patients with type II diabetes mellitus: A randomized controlled clinical trial. Clin Nutr. 2019;38:549-556.
  38. Maierean SM, Serban MC, Sahebkar A, et al. The effects of cinnamon supplementation on blood lipid concentrations: A systematic review and meta-analysis. J Clin Lipidol. 2017 Nov - Dec;11(6):1393-1406.
  39. Hajimonfarednejad M, Nimrouzi M, Heydari M, Zarshenas MM, Raee MJ, Jahromi BN. Insulin resistance improvement by cinnamon powder in polycystic ovary syndrome: A randomized double-blind placebo controlled clinical trial. Phytother Res. 2018 Feb;32(2):276-283.
  40. Gupta Jain S, Puri S, Misra A, Gulati S, Mani K. Effect of oral cinnamon intervention on metabolic profile and body composition of Asian Indians with metabolic syndrome: a randomized double -blind control trial. Lipids Health Dis. 2017 Jun 12;16(1):113.
  41. Mertens M, Gilissen L, Goossens A, Lambert J, Vermander E, Aerts O. Generalized systemic allergic dermatitis caused by Cinnamomum zeylanicum in a herbal tea. Contact Dermatitis. 2017 Oct;77(4):259-261.
  42. Hajimonfarednejad M, Ostovar M, Raee MJ, Hashempur MH, Mayer JG, Heydari M. Cinnamon: A systematic review of adverse events. Clin Nutr. 2019 Apr;38(2):594-602.
  43. Chan J, Oshiro T, Thomas S, et al. Inactivation of CYP2A6 by the Dietary Phenylpropanoid trans-Cinnamic Aldehyde (Cinnamaldehyde) and Estimation of Interactions with Nicotine and Letrozole. Drug Metab Dispos. 2016 Apr;44(4):534-43.
  44. Taheri A, Lavasani H, Kasirzadeh S, Sheikholeslami B, Ardakani YH, Rouini MR. Changes in CYP2D enzyme activity following induction of type 2 diabetes, and administration of cinnamon and metformin: an experimental animal study.Xenobiotica. 2018 Oct;48(10):984-989.
  45. Mamindla S, Koganti VSRGP, Ravouru N, Koganti B. Effect of Cinnamomum cassia on the Pharmacokinetics and Pharmacodynamics of Pioglitazone. Curr Clin Pharmacol. 2017;12(1):41-49.
  46. Mirmiran P, Davari M, Hashemi R, et al. A randomized controlled trial to determining the effect of cinnamon on the plasma levels of soluble forms of vascular adhesion molecules in type 2 diabetes mellitus. Eur J Clin Nutr. Dec 2019;73(12):1605-1612.
  47. Davari M, Hashemi R, Mirmiran P, et al. Effects of cinnamon supplementation on expression of systemic inflammation factors, NF-kB and Sirtuin-1 (SIRT1) in type 2 diabetes: a randomized, double blind, and controlled clinical trial. Nutr J. Jan 4 2020;19(1):1.
  48. Namazi N, Khodamoradi K, Khamechi SP, et al. The impact of cinnamon on anthropometric indices and glycemic status in patients with type 2 diabetes: A systematic review and meta-analysis of clinical trials. Complement Ther Med. Apr 2019;43:92-101.
  49. Vallianou N, Tsang C, Taghizadeh M, et al. Effect of cinnamon (Cinnamomum zeylanicum) supplementation on serum C-reactive protein concentrations: A meta-analysis and systematic review. Complement Ther Med. Feb 2019;42:271-278.
  50. Pender DN, Crawford PF, Clark JM, et al. Effect of water-soluble cinnamon extract on electrocardiographic parameters: An analysis of the CiNNaMON trial. Complement Ther Med. Dec 2018;41:302-305.
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