Summary: In a triple-blind placebo-controlled trial in type 2 diabetes, 3 g/day of cinnamon for 90 days produced small numerical reductions in weight, BMI, and waist measures, but none reached statistical significance. The trial was negative for weight outcomes.
PICO Summary
| Element | Detail |
|---|---|
| Population | 140 adults with type 2 diabetes (69% women, mean age 61); Brazil. |
| Intervention | 3 g/day encapsulated cinnamon (Cinnamomum verum) for 90 days (n=71). |
| Comparison | Placebo (n=69); triple-blind. |
| Outcome | Non-significant reductions in weight (-0.8 kg, p=0.11), BMI (-0.36, p=0.16), body adiposity index (-1.02%, p=0.38), waist (-3.97 cm, p=0.67), neck (-0.45 cm, p=0.68), and hip circumference (-1.83 cm, p=0.49). All p>0.05. |
Cinnamon for weight in type 2 diabetes
RCT · type 2 diabetes · 90 days
Cinnamon 3 g/day for 90 days produced only small, non-significant reductions in weight and other anthropometric measures. The trial was negative for weight loss.
Expert Commentary
This is a clean negative trial, and I value it precisely for that. Cinnamon is among the most heavily marketed supplements for metabolic health, so a well-designed, triple-blind, placebo-controlled study of meaningful size, reporting honestly that none of its anthropometric outcomes reached significance, is genuinely useful in clinic. The numbers drift in the expected direction but the p-values make clear these are noise, not signal, and the authors deserve credit for not dressing small non-significant changes up as a trend worth chasing. My one caveat is the usual one for botanical studies: a different cinnamon species, dose, or duration might behave differently, and the trial may have been modestly powered for small effects, so this closes the door on weight loss at this dose rather than on cinnamon universally. Can I use this with my patients? Yes, directly and often. When a patient asks whether cinnamon capsules will help them lose weight, I can now give an evidence-based no, reassure them the spice is perfectly fine in food, and redirect the conversation and their money toward the things that actually work, diet, activity, and proven pharmacotherapy. Negative trials like this protect patients from false hope.
References
Lira Neto JCG, Araújo MFM, Penha JCD, et al. Efficacy of cinnamon in reducing anthropometric measurements in individuals with type 2 diabetes: a clinical trial. Rev Bras Enferm. 2025;78(3):e20240380. doi:10.1590/0034-7167-2024-0380