HerbModerate Evidence

Cinnamon

Cinnamomum verum / Cinnamomum cassia

A popular warming spice studied for blood sugar and cholesterol support. Ceylon ('true') cinnamon is preferred over cassia for regular supplementation because of cassia's high coumarin content.

What is Cinnamon?

Cinnamon is a spice made from the inner bark of trees in the genus Cinnamomum. Two main types are sold: Ceylon cinnamon (Cinnamomum verum), known as 'true' cinnamon, and the more common, cheaper cassia cinnamon (Cinnamomum cassia). Beyond its role as a baking and beverage spice, cinnamon has been studied for metabolic health, with the distinction between Ceylon and cassia being important for safe long-term use.

Known Health Benefits

May modestly improve fasting blood sugar and HbA1c
May support healthy cholesterol and triglyceride levels
Provides antioxidant and anti-inflammatory polyphenols
Has antimicrobial properties

How It Works

Cinnamon's metabolic effects are driven largely by cinnamaldehyde and polyphenol procyanidins, which appear to improve insulin sensitivity by enhancing insulin-receptor signaling and increasing glucose uptake into cells via GLUT4 translocation. Cinnamon also slows gastric emptying and inhibits digestive enzymes that break down carbohydrates, blunting post-meal blood-sugar spikes. Its polyphenols provide antioxidant and anti-inflammatory activity, and cinnamaldehyde has antimicrobial effects. The coumarin found mainly in cassia is unrelated to these benefits and is responsible for the liver-toxicity concern at high intakes.

What Research Says

Meta-analyses of cinnamon for type 2 diabetes show modest but statistically significant reductions in fasting blood glucose and improvements in lipid profiles, though effects on HbA1c are inconsistent and trial quality varies. A 2013 meta-analysis by Allen et al. in Annals of Family Medicine found significant reductions in fasting glucose, total and LDL cholesterol, and triglycerides. Results differ by cinnamon type and dose, and cinnamon is best considered a complementary aid rather than a substitute for proven diabetes management.

Active Compounds

Cinnamaldehyde, cinnamic acid, procyanidins, eugenol

Forms & Bioavailability

Ceylon cinnamon powder or sticks (preferred for supplementation)Cassia cinnamon powder (culinary)Standardized water-extract capsulesCinnamon tea

Cinnamaldehyde and polyphenols are absorbed in the gut, though water-soluble cinnamon extracts (which concentrate the active polyphenols while minimizing fat-soluble coumarin) are often used in clinical studies for better consistency and safety. Taking cinnamon with carbohydrate-containing meals aligns with its blood-sugar-modulating effect.

Dosage Guidance

Use CaseDosage
Blood sugar support1–6 g Ceylon daily
Cholesterol support1–6 g daily
Culinary / antioxidantTo taste

Always consult a healthcare provider for personalized dosing.

Potential Side Effects

Culinary use is safe. Cassia cinnamon is high in coumarin, which in large daily amounts can be hepatotoxic and may increase bleeding risk. Ceylon cinnamon contains far less coumarin and is safer for supplementation.

Who Should Avoid It

  • Liver disease (especially with high-coumarin cassia)
  • Anticoagulant therapy (coumarin/bleeding risk)
  • Upcoming surgery
  • Pregnancy in medicinal doses (culinary use is fine)

Pregnancy & Lactation

Culinary amounts of cinnamon are safe during pregnancy and breastfeeding. Concentrated supplemental doses, particularly of cassia, are not recommended due to coumarin content and limited safety data.

Known Drug Interactions

May add to blood-sugar-lowering and anticoagulant medications. High-coumarin cassia may interact with warfarin and stress the liver alongside hepatotoxic drugs.

Evidence Classification

Moderate Evidence

Supported by cohort studies, case-control studies, or multiple observational studies with consistent findings.

Frequently Asked Questions

What is the difference between Ceylon and cassia cinnamon?

Ceylon ('true') cinnamon is lighter, more delicate, and very low in coumarin, while cassia is darker, stronger, cheaper, and high in coumarin — a compound that can harm the liver in large daily amounts. For regular supplementation, Ceylon is the safer choice.

Does cinnamon lower blood sugar?

Meta-analyses show cinnamon can modestly reduce fasting blood glucose and improve cholesterol, but effects on long-term HbA1c are inconsistent. It may be a helpful complement to diet, exercise, and medication, but not a replacement for them.

How much cinnamon is too much?

The concern is coumarin in cassia cinnamon. European safety bodies set a tolerable daily coumarin intake that just a teaspoon or two of cassia can exceed for smaller individuals. Choosing Ceylon cinnamon largely removes this concern.

References

  1. Cinnamon use in type 2 diabetes: an updated systematic review and meta-analysis. Allen RW, Schwartzman E, Baker WL, Coleman CI, Phung OJ. Ann Fam Med (2013)View study
  2. Cinnamon: a multifaceted medicinal plant. Rao PV, Gan SH. Evid Based Complement Alternat Med (2014)View study

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This entry is for educational purposes only. It is not medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement regimen, especially if you take medications or have health conditions.