Two Cinnamons, One Word, And A Liver Limit

Two Different Plants

Cinnamon comes from the bark of trees in the Cinnamomum genus, and several species are sold under the same word.

Cassia — usually Cinnamomum cassia or C. burmannii — is grown in China, Indonesia and Vietnam. It is darker, stronger, cheaper, and it makes up the overwhelming majority of the western market.

Ceylon, Cinnamomum verum, comes mainly from Sri Lanka. It is paler, milder, more complex in flavour, and considerably more expensive. It is sometimes called true cinnamon, which is a marketing name as much as a botanical one.

Both are real cinnamon. They are simply different species with different chemistry, and the label word does not distinguish them.

The Coumarin Problem

Coumarin is a naturally occurring compound with a sweet hay-like smell. It is also hepatotoxic in sustained high intakes, which is why food safety authorities have set a limit.

The European Food Safety Authority tolerable daily intake is 0.1 mg of coumarin per kilogram of body weight. For a 70 kg adult that is 7 mg a day — which cassia powder can reach in about a teaspoon, depending on the batch.

Where This Does And Does Not Matter

Perspective first, because this is not a reason to be frightened of a spice.

Not a problem: cinnamon on porridge, in a bake, in a coffee. Occasional culinary amounts are well inside the limit for almost everyone.

Worth thinking about: a heaped teaspoon of cassia every single morning for months, which some people do specifically for blood sugar.

Worth checking: a dedicated cinnamon supplement at gram doses. This is where intakes climb without anyone noticing, because the trials that motivated those products used one to six grams a day.

Almost irrelevant: cinnamon inside a small multi-ingredient blend. Whatever cinnamon is in a blend like GlycoAid is a fraction of a 500 mg total shared fourteen ways, and the coumarin exposure from it is negligible. That is the reassuring half of this article.

How To Tell What You Have

1. Look at the sticks. This is the reliable test. Ceylon quills are made of many paper-thin layers rolled together and crumble easily. Cassia is one thick hard curl.
2. Look at the colour. Ceylon is light tan, cassia is dark reddish brown.
3. Look at the price. If it is cheap, it is cassia. There is no cheap Ceylon.
4. Read the label for a species name. Cinnamomum verum or Ceylon will be stated, because it is a selling point. Anything saying only "cinnamon" is cassia.
5. Ask the seller for a supplement. A brand using Ceylon advertises it. A brand that cannot answer has told you something.

Does Either One Help Blood Sugar?

Honestly, not much, and the answer does not depend on the species.

The human trials are weak and inconsistent for both. Some report small reductions in fasting glucose and others find nothing, and meta-analyses have landed on both sides depending on which studies they include. Cinnamon Bark goes through the evidence in full.

So the practical position is this: if you enjoy cinnamon, use it, preferably Ceylon if you use it daily. Do not take a gram-dose cassia supplement for glucose, because you would be accepting a real coumarin exposure in exchange for a weak and disputed benefit.