Efficacy of Cinnamon as an Adjuvant in Reducing the Glycemic Biomarkers of Type 2 Diabetes Mellitus: A Three-Month, Randomized, Triple-Blind, Placebo-Controlled Clinical Trial

J Am Nutr Assoc. 2022 Mar-Apr;41(3):266-274. doi: 10.1080/07315724.2021.1878967. Epub 2021 Feb 19.


The major aim of this randomized, placebo-controlled, triple-blind clinical trial was to evaluate the efficacy of cinnamon as an adjuvant treatment in reducing glycemic levels in people with type 2 diabetes, compared to a placebo. The study was conducted between August and December 2019, with 160 people with type 2 diabetes, in five Primary Health Units, in Parnaíba, Brazil. Inclusion criteria were: persons of both genders using oral antidiabetic agents, with glycated hemoglobin ≥ 6.0%, and between 18 and 80 years of age. The primary outcome was change in glycated hemoglobin levels after 90 days of intervention. Other biomarkers evaluated were fasting blood glucose, insulin level, and HOMA-IR index. Participants were divided equally into two groups of 80 individuals each, and were given 3 g capsules of either cinnamon or placebo to be taken in combination with their usual oral antidiabetic agents. After 90 days, participants in the cinnamon group had statistically significant reductions of 0.2% of glycated hemoglobin and 0.55 mmol/L of fasting venous glucose, when compared with the placebo group. Cinnamon reduced the glycemic measures of persons with type 2 diabetes, albeit with modest reductions. TRIAL: RBR-2KKB6D.

Keywords: Cinnamon; clinical trial; glucose; placebo; type 2 diabetes mellitus.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adjuvants, Immunologic / therapeutic use
  • Adjuvants, Pharmaceutic / therapeutic use
  • Biomarkers
  • Blood Glucose*
  • Cinnamomum zeylanicum
  • Diabetes Mellitus, Type 2* / drug therapy
  • Female
  • Glycated Hemoglobin / therapeutic use
  • Humans
  • Hypoglycemic Agents / therapeutic use
  • Male


  • Adjuvants, Immunologic
  • Adjuvants, Pharmaceutic
  • Biomarkers
  • Blood Glucose
  • Glycated Hemoglobin A
  • Hypoglycemic Agents