Supplements · Diets · Metabolic & Cardiometabolic
Does cinnamon lower fasting blood sugar?
The claim, precisely: cinnamon decreases fasting glucose
Probably modestly yes, but the evidence is shaky, results vary, and high doses risk toxicity.
Evidence ladder
How far up the ladder this claim has climbed. A high consensus on a low rung means "consistent so far," not "proven in people."
Top evidence so far: All trials, pooled (Meta-analysis)
How the studies fall
What the evidence shows
Cinnamon's glycemic effect is real-but-fragile and heterogeneous; a 2025 GRADE MA finds significant-but-controversial effects while the 2012 Cochrane review found insufficient evidence. Coumarin (cassia) toxicity caps dose — a flavor lever, not a defensible glucose claim.
The evidence (5)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| (GRADE SR/MA) 2025 · (SR/MA) | meta-analysis | supports | low | GRADE MA: significant but heterogeneous/controversial glycemic effects |
| Leach MJ, Kumar S 2012 · Cochrane Database Syst Rev | meta-analysis | tested-null | high | [FT-verified] Cochrane: insufficient evidence cinnamon improves glycemia |
| Moridpour 2024 · Phytother Res | meta-analysis | supports | moderate | [FT-verified] 24-RCT FBS SMD -1.32 but high heterogeneity, cassia-dominated low-quality |
| Leach MJ, Kumar S 2012 · Cochrane Database Syst Rev | meta-analysis | tested-null | moderate | Insufficient evidence for glycemic benefit |
| Mandal 2021 · Cureus | meta-analysis | contradicts | low | Cassia bark 1-2g/day x90d in T2D: insignificant reduction in fasting glucose and lipids |
Educational only, not medical advice. Grades and scores reflect published evidence weighted by study design and quality; see the methodology.