Supplements · Diets · Metabolic & Cardiometabolic

cinnamon decreases fasting glucose

In plain terms: Does cinnamon meaningfully lower blood sugar?

Leans support Supplements 🔬 Includes disconfirming

RefutedContestedStrong support

consensus score 0.51

Cinnamon can blunt acute postprandial glucose in small trials but reviews find no reliable HbA1c/fasting benefit — the general "lowers glucose" claim is contested and weak in healthy people.

📅 Last reviewed: 2026-07-14 ⓘ

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)

MechanismIn-vitroAnimalObservationalRCTMeta-analysis

How the studies fall

8 support 0 contradict 3 tested null 4 mixed · 15 sources, 8 independent groups

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.

Cochrane has no ruling yet see how our grade compares ▾

Cochrane · not stated as GRADE Not directly comparable

authors describe evidence as limited/low quality (high or unclear risk of bias in all but two trials)

“There is insufficient evidence to support the use of cinnamon for type 1 or type 2 diabetes mellitus. The effect of cinnamon on fasting blood glucose level was inconclusive, with no statistically significant differences between cinnamon and control across measured glycemic outcomes; risk of bias was high or unclear in all but two trials.”

Not directly comparable: their review asks a different question or reports an outcome we do not grade, so it neither corroborates nor contradicts this claim.

What is Cochrane, and why trust it?

Cochrane produces systematic reviews: instead of running a new study, they gather every trial ever done on a question, judge how well each was run, and pool the results. They take no commercial or industry funding, which is why the medical community treats their reviews as a gold standard — and why we check our own verdicts against theirs.

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The evidence (15)

Source	Grade	Stance	Quality	Finding
Allen 2013 · Ann Fam Med	meta-analysis	supports	moderate	Updated RCT meta-analysis: cinnamon significantly lowered fasting glucose and lipids
Beejmohun 2014 · BMC Complement Altern Med	RCT	tested-null	low	Ceylon cinnamon extract acutely reduced postprandial glucose via alpha-amylase inhibition in healthy volunteers; single small acute trial.
(GRADE SR/MA) 2025 · (SR/MA)	meta-analysis	supports	low	GRADE MA: significant but heterogeneous/controversial glycemic effects
Zelicha 2024 · Am J Clin Nutr	RCT	supports	moderate	4-wk CGM crossover prediabetes; cinnamon spice lowered continuous glycemic response
Romeo 2020 · J Endocr Soc	RCT	mixed	moderate	Prediabetes RCT: cinnamon lowered fasting glucose and blunted excursions vs placebo
Sabzevari Rad R 2025 · J Int Soc Sports Nutr	RCT	mixed	low	In overweight/obese soldiers, 8 weeks of cinnamon supplementation (500mg capsules, 3x/day) combined with or without Tabata training significantly decreased fasting blood sugar, insulin, and HOMA-IR across all intervention groups (
Ranasinghe 2012 · Diabet Med	meta-analysis	mixed	moderate	SR/meta of Cinnamomum zeylanicum: some glycemic signal but evidence limited and inconsistent.
Leach MJ, Kumar S 2012 · Cochrane Database Syst Rev	meta-analysis	tested-null	high	[FT-verified] Cochrane: insufficient evidence cinnamon improves glycemia
Ranasinghe 2025 · Diabetes Metab Syndr	RCT	supports	moderate	Ceylon cinnamon extract RCT in T2DM; antihyperglycemic effect on glycemia
Moridpour 2024 · Phytother Res	meta-analysis	supports	moderate	[FT-verified] 24-RCT FBS SMD -1.32 but high heterogeneity, cassia-dominated low-quality
Deyno 2019 · Diabetes Res Clin Pract	meta-analysis	supports	moderate	Meta-analysis+meta-regression T2DM/prediabetes: cinnamon reduced fasting glucose
Lira Neto 2022 · J Am Nutr Assoc	RCT	supports	moderate	3g/day x90d in 160 T2DM: modest 0.55 mmol/L fasting glucose drop vs placebo
Muthukuda 2025 · PLoS One	RCT	supports	moderate	C. zeylanicum extract RCT; glucose secondary endpoint, effect modest
de Moura 2025 · Nutr Rev	meta-analysis	mixed	moderate	SR/MA cinnamon on metabolic biomarkers T2DM; glucose effect modest, biomarker-dependent
Mandal 2021 · Cureus	meta-analysis	tested-null	low	Cassia bark 1-2g/day x90d in T2D: insignificant reduction in fasting glucose and lipids

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