EC Clinical and Medical Case Reports

Cinnamon (Cinnamomum) is often marketed as a natural remedy for various health conditions, which requires verification. This systematic review evaluates the clinical and preclinical evidence behind cinnamon’s purported health benefits. Following a database search of literature published up to 31 December 2025 in PubMed and followed by six inclusion criteria, 26 of the original 201 studies were included. These studies were grouped into four categories: (i) cardiometabolic health and glycemic regulation; (ii) anti- inflammatory, antioxidant and tissue protection; (iii) other bioactive effects including antimicrobial and longevity; and (iv) safety and toxicology. The most robust finding across the literature is that cinnamon acutely blunts post-prandial glucose spikes in healthy and overweight adults, while significantly reducing post-prandial insulin specifically in overweight and obese populations. Beyond this short-term effect, the clinical evidence is inconsistent. Results for long-term blood sugar control (HbA1c) are mixed. Though animal studies show cardiovascular benefits, human trials do not. Furthermore, claims regarding brain health, gut health, antimicrobial effects, and reproduction have not been proven in humans. Safety data is incomplete. Low doses (up to 500 mg/day) appear safe for healthy adults but providing standard clinical doses to lactating animals cause metabolic issues in their offspring. In conclusion, cinnamon is a useful dietary addition for managing post-meal blood sugar but current evidence does not support broader medical claims. To establish true clinical utility, future research requires chemically standardized extracts, thorough safety testing, and larger human trials lasting at least 12 weeks.

Keywords: Cinnamon (Cinnamomum); Health Benefits; HbA1c

1. Ranasinghe P., et al. “Evaluation of pharmacodynamic properties and safety of Cinnamomum zeylanicum (Ceylon cinnamon) in healthy adults: a phase I clinical trial”. BMC Complementary and Alternative Medicine1 (2017): 550.
2. Mandal A., et al. “Efficacy of young Cinnamomum zeylanicum blume bark on hyperglycemia and PTPase activity in type 2 diabetes”. Cureus 2 (2023): e35023.
3. Kizilaslan N and Erdem NZ. “The effect of different amounts of cinnamon consumption on blood glucose in healthy adult individuals”. International Journal of Food Science (2019): 4138534.
4. Park TG., et al. “Cinnamon (Cinnamomum cassia) hot water extract improves inflammation and tight junctions in the intestine in vitro and in vivo”. Food Science and Biotechnology13 (2023): 1925-1933.
5. Camacho S., et al. “Anti-obesity and anti-hyperglycemic effects of cinnamaldehyde via altered ghrelin secretion and functional impact on food intake and gastric emptying”. Scientific Reports1 (2015): 7919.
6. Xu Q., et al. “A-type cinnamon procyanidin oligomers protect against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced neurotoxicity in mice through inhibiting the P38 mitogen-activated protein kinase/P53/BCL-2 associated X protein signaling pathway”. The Journal of Nutrition7 (2020): 1731-1737.
7. Hosny KM., et al. “Development and optimization of cinnamon oil nanoemulgel for enhancement of solubility and evaluation of antibacterial, antifungal and analgesic effects against oral microbiota”. Pharmaceutics7 (2021): 1008.
8. Sengsuk C., et al. “Effect of cinnamon supplementation on glucose, lipids levels, glomerular filtration rate, and blood pressure of subjects with type 2 diabetes mellitus”. Diabetology International2 (2016): 124-132.
9. International Diabetes Federation. IDF Diabetes Atlas (2025).
10. World Health Organization. “Obesity and overweight” (2024).
11. World Health Organization. “Cardiovascular diseases (CVDs)” (2021).
12. Hashemian M., et al. “Turmeric, pepper, cinnamon, and saffron consumption and mortality”. Journal of the American Heart Association18 (2019): e012240.
13. Davari M., 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”. Nutrition Journal1 (2020): 1.
14. Khaki A., et al. “The anti-oxidant effects of ginger and cinnamon on spermatogenesis dys-function of diabetes rats”. African Journal of Traditional, Complementary and Alternative Medicines4 (2014): 1.
15. Vanschoonbeek K., et al. “Cinnamon supplementation does not improve glycemic control in postmenopausal type 2 diabetes patients”. The Journal of Nutrition4 (2006): 977-980.
16. Azimi P., et al. “Effect of cinnamon, cardamom, saffron and ginger consumption on blood pressure and a marker of endothelial function in patients with type 2 diabetes mellitus: A randomized controlled clinical trial”. Blood Pressure3 (2016): 133-140.
17. Mirmiran P., 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”. European Journal of Clinical Nutrition12 (2019): 1605-1612.
18. Liberati A., et al. “The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration”. PLoS Medicine7 (2009): e1000100.
19. Wang J., et al. “Acute effects of cinnamon spice on post-prandial glucose and insulin in normal weight and overweight/obese subjects: a pilot study”. Frontiers in Nutrition 7 (2021): 619782.
20. Huang Y., et al. “Endothelial function and postprandial glucose control in response to test-meals containing herbs and spices in adults with overweight/obesity”. Frontiers in Nutrition 9 (2022): 811433.
21. Al Dhaheri AS., et al. “The effect of therapeutic doses of culinary spices in metabolic syndrome: a randomized controlled trial”. Nutrients11 (2024): 1685.
22. Sabzevari Rad R., et al. “The combined effects of Tabata training and cinnamon supplementation on metabolic changes and body composition in soldiers with overweight or obesity”. Journal of the International Society of Sports Nutrition1 (2025): 2564237.
23. Badalzadeh R., et al. “The effect of cinnamon extract and long-term aerobic training on heart function, biochemical alterations and lipid profile following exhaustive exercise in male rats”. Advanced Pharmaceutical Bulletin (2014).
24. Sedighi M., et al. “Protective effects of cinnamon bark extract against ischemia-reperfusion injury and arrhythmias in rat”. Phytotherapy Research10 (2018): 1983-1991.
25. Van Hul M., et al. “Reduced obesity, diabetes, and steatosis upon cinnamon and grape pomace are associated with changes in gut microbiota and markers of gut barrier”. American Journal of Physiology-Endocrinology and Metabolism4 (2018): E334-E352.
26. Neto JGO., et al. “Cinnamaldehyde treatment during adolescence improves white and brown adipose tissue metabolism in a male rat model of early obesity”. Food and Function6 (2022): 3405-3418.
27. Madhavadas S and Subramanian S. “Cognition enhancing effect of the aqueous extract of Cinnamomum zeylanicum on non-transgenic Alzheimer’s disease rat model: Biochemical, histological, and behavioural studies”. Nutritional Neuroscience9 (2017): 526-537.
28. Im JA., et al. “Animal model of intestinal anti-inflammatory effect of ginger-cinnamon complex”. Food Science and Biotechnology9 (2021): 1249-1256.
29. Sorour S., et al. “Anticoccidial and hepatoprotective effects of artemisinin liquid extract, cinnamon essential oil and clove essential oil against Eimeria stiedae infection in rabbits”. Tropical Biomedicine 4 (2018): 926-943.
30. Neto JGO., et al. “Maternal cinnamon intake during lactation led to visceral obesity and hepatic metabolic dysfunction in the adult male offspring”. Endocrine3 (2019): 520-530.