Ceylon cinnamon is the bark of Cinnamomum verum, a tree native to Sri Lanka and southern India. It’s often called “true cinnamon” to distinguish it from cassia, the more common and less expensive variety that fills most spice racks. The key reason people seek it out: Ceylon cinnamon contains roughly 0.004% coumarin, a compound that can stress the liver in large amounts, compared to up to 1% coumarin in cassia cinnamon.
Ceylon vs. Cassia: Why There Are Two Cinnamons
At least four species of Cinnamomum tree produce bark sold as “cinnamon,” but two dominate the market. Ceylon cinnamon comes from Cinnamomum verum, grown primarily in Sri Lanka. Cassia cinnamon comes from Cinnamomum aromaticum, originating in China and Burma. The two have been confused, sometimes intentionally, for centuries. A 15th-century English etiquette manual even distinguished between cinnamon for lords and cassia for commoners.
If you buy ground cinnamon at a typical grocery store in North America, you’re almost certainly buying cassia. Ceylon cinnamon is rarer, more expensive, and usually needs to be sourced from specialty shops or online retailers. The flavor differences are subtle but real: Ceylon tends to be lighter and more complex, while cassia is bolder and more pungent.
How to Tell Them Apart
In stick form, the two are easy to distinguish. Ceylon cinnamon sticks are tan-brown, with many thin, soft layers rolled tightly together, almost like a cigar. Cassia sticks are dark brown-red, thicker, rougher in texture, and usually curled into a single hollow tube. Once ground into powder, though, they look nearly identical, which is why labeling matters.
Why Coumarin Content Matters
The biggest practical difference between Ceylon and cassia cinnamon is coumarin. Cassia contains up to 1% coumarin by weight. Ceylon contains only trace amounts, around 0.004%, and some Sri Lankan samples have tested as essentially coumarin-free.
Coumarin is naturally occurring and harmless in small quantities, but at higher doses over time it can cause liver damage. The European Food Safety Authority set a tolerable daily intake of 0.1 mg per kilogram of body weight. For a 70 kg (154 lb) person, that’s 7 mg per day. A single teaspoon of cassia cinnamon (roughly 2.5 g) can contain up to 25 mg of coumarin, well above that threshold. The same amount of Ceylon cinnamon would contain a negligible 0.1 mg.
This distinction matters most for people who consume cinnamon daily, whether sprinkled on oatmeal, added to smoothies, or taken as a supplement. Occasional use of cassia in cooking is not a concern. But if you’re using cinnamon regularly for its potential health benefits, Ceylon is the safer long-term choice.
Effects on Blood Sugar and Metabolism
Cinnamon’s most studied health effect is its influence on blood sugar. Lab and animal studies show that cinnamon enhances glucose uptake by activating the insulin receptor, essentially helping your cells respond better to insulin. It also appears to increase glycogen synthesis, which is how your body stores sugar for later use. One notable finding is that cinnamon lowers blood sugar within normal physiological ranges without causing dangerous drops, suggesting it works by amplifying insulin’s natural effects rather than acting like a drug.
Clinical trials in people with type 2 diabetes and prediabetes have used cinnamon at doses ranging from 500 mg to 6 g per day, typically for 8 to 16 weeks. A meta-analysis of nine trials found benefits for blood pressure, weight, and waist circumference in type 2 diabetic patients taking 1 to 4.5 g daily for two to three months. No significant adverse effects were reported at doses up to 6 g per day. Most of these trials used cinnamon powder or extract, and not all specified the species, which is a limitation worth noting.
Beyond blood sugar, smaller trials have explored cinnamon for other conditions. A 60-day trial of Ceylon cinnamon at 600 mg per day found reduced migraine frequency and severity. Another study found that 1,500 mg per day for six months improved menstrual regularity in women with polycystic ovary syndrome. These are preliminary findings from small studies, but they point to a broader metabolic role.
Antioxidant Profile
Cinnamon is one of the most antioxidant-rich spices. Its total phenolic content ranges widely depending on how it’s extracted, from about 4 mg per gram with basic methods up to 165 mg per gram with advanced techniques. Researchers have identified at least 14 phenolic acids common to cinnamon varieties. Cassia tends to have more free-form phenolic compounds, while Ceylon cinnamon has higher levels locked in its cell walls, which may release more slowly during digestion.
The essential oil composition also differs between the two. Ceylon cinnamon bark oil is rich in cinnamaldehyde (the compound responsible for cinnamon’s signature smell and taste), while its leaf oil contains mostly eugenol, a compound also found in cloves. Cassia produces cinnamaldehyde-rich oil from both bark and leaves. For culinary purposes this distinction is minor, but it matters in essential oil production and aromatherapy.
How Much to Use
For general culinary use, there’s no specific limit. Cinnamon has FDA “Generally Recognized as Safe” status as a food ingredient. For people using it more deliberately, clinical studies have typically used 1 to 3 g per day (roughly half a teaspoon to a full teaspoon of ground cinnamon), with some trials going as high as 6 g daily without reported problems.
If you’re choosing between the two varieties for daily use, the math on coumarin makes the decision straightforward. At 1 teaspoon per day of cassia, you’d exceed the European safety threshold for coumarin by more than three times. The same amount of Ceylon cinnamon keeps you well within safe limits. For occasional baking or cooking, either variety is fine. For a daily habit, Ceylon is the better option.
Ceylon cinnamon supplements are widely available in capsule form, usually in doses of 500 to 1,200 mg. These are concentrated and standardized, which removes the guesswork of measuring powder. Look for labels that specifically say “Ceylon” or “Cinnamomum verum” rather than just “cinnamon,” since cassia-based products are more common and cheaper to produce.