Cinnamon and blood sugar — does it actually work?

The real research behind cinnamon as a glucose-lowering supplement, dosing, and which type to use.

Written by

Carb Lens Editorial

Nutrition writers & product team

Medically reviewed by

Dr. Alicia Nguyen, RD, CDCES

Registered Dietitian · Certified Diabetes Care & Education Specialist · 12+ years clinical experience

Published July 13, 2026 3 min readEditorial policy

Cinnamon is one of the most-studied spices for blood sugar. The evidence is real but modest — and the type matters.

What the studies show

Meta-analyses: cinnamon lowers fasting glucose by 5–25 mg/dL
HbA1c reduction: 0.27% on average
Effect is more pronounced in people with poor baseline control
Effect plateaus after 8–12 weeks for some

Ceylon vs Cassia cinnamon

There are two main types:

### Cassia (the usual supermarket type) - Cheaper - Stronger flavor - Contains coumarin, which can damage the liver in high doses - Limit: 1 tsp/day max

### Ceylon ("true cinnamon") - More expensive - Milder, sweeter flavor - Minimal coumarin - Safe at higher doses

For long-term daily use, choose Ceylon.

Effective dose

1–3g per day (½ to 1 teaspoon)
Split into 2 doses for better effect
Take with meals containing carbs

How to use it

Sprinkle on Greek yogurt, oats, coffee
Stir into smoothies
Use in spice rubs and curries
Capsules if you don't like the taste

Realistic expectations

Cinnamon is not a substitute for diet, exercise or medication. The effect is real but small — think of it as a 5% bonus on top of the fundamentals.

Cautions

Cassia in high doses can affect the liver — don't take cinnamon supplements daily without coumarin-free assurance
Cinnamon can mildly thin blood — caution with blood thinners
May interact with insulin/sulfonylureas — monitor for lows
Discuss with your doctor before starting

About the author

Carb Lens Editorial — Nutrition writers & product team. The Carb Lens editorial team writes practical, source-checked guides on carbs, blood sugar, and everyday nutrition. Every article is drafted by our writers and cross-referenced against USDA FoodData Central and peer-reviewed clinical guidelines.

How we source and review this article

Nutrition figures come from the USDA FoodData Central database. Blood-sugar and glycemic-load framing follows guidance from the American Diabetes Association and World Health Organization healthy-diet recommendations. Every article is medically reviewed by Dr. Alicia Nguyen, RD, CDCES before publishing and re-checked on a rolling basis. See our full editorial & medical review policy.

This article is for general information and is not a substitute for medical advice. If you're managing diabetes or another condition, always defer to your care team.