What are cinnamon’s main benefits?

Cinnamon is claimed to treat several conditions, including diabetes and cardiovascular disease, respiratory and digestive disorders, and neurodegenerative conditions like Parkinson’s disease and Alzheimer’s disease.^[1][2][3][4] Some in vitro and animal studies have yielded promising results, but clinical evidence is lacking for many of these conditions.

In humans, some meta-analyses of randomized controlled trials have shown that cinnamon can improve glycemic control (reduced blood glucose and HbA1c),^{[5][6][7][8][9]} blood lipids (decreased triglycerides, LDL, total cholesterol),^{[10][11][12][13][14][15]} and blood pressure.^[16][17][18] Supplementation with cinnamon might also improve some biomarkers of inflammation and oxidative stress, including reduced plasma concentrations of interleukin 6 and C-reactive protein.^[19][20][10] Therefore, cinnamon might be useful for the treatment of diabetes and cardiovascular disease. However, many clinical studies have a moderate to high risk of bias,^{[21][22][8][6][10][12][19]} and many of the meta-analyses cited here find large variability (substantial heterogeneity) in the size of the effect between studies. Furthermore, large observational studies show that LDL, HDL, and HbA1c are not different between people who regularly consume cinnamon versus people who do not.^[21] Consequently, more well-controlled randomized clinical trials are needed to definitively establish cinnamon's health benefits in humans.