What are the safety differences between Cassia and Ceylon cinnamon, especially regarding coumarin exposure?

1. The botanical and chemical split: what "Ceylon" and "Cassia" actually mean

Ceylon cinnamon (Cinnamomum verum) is often called “true cinnamon” and is characterized by thin, multi-layered bark and very low coumarin levels, whereas several commercial varieties grouped as Cassia (including Chinese, Saigon, and Korintje types) are from different Cinnamomum species with thicker, single‑layer bark and substantially higher coumarin content ^{[1] [4] [5]}.

2. How much coumarin are we talking about?

Measured coumarin concentrations differ dramatically: multiple retail surveys and analyses found Cassia samples with mean coumarin levels in the low thousands of mg/kg (for example, 2,650–7,017 mg·kg−1 in one Czech market study) while pure Ceylon samples tested near single‑digit parts per billion or only trace amounts (for example, a Canadian inspection sample measured 6.8 ppb) ^{[1] [2]}. Other summaries report Cassia having roughly 63× the coumarin of Ceylon powder on average, or orders of magnitude higher depending on the study and variety ^{[4] [3]}.

3. What the science and regulators say about risk (TDI and liver concerns)

European authorities and national risk bodies have specified tolerable daily intakes for coumarin (EFSA and Germany’s BfR referencing about 0.1 mg/kg body weight), and regulators have warned that habitual, large doses of Cassia powder or supplements can push consumers past those limits and might elevate liver enzymes or in rare cases cause liver inflammation in sensitive people ^{[2] [3]}. Studies translating measured coumarin concentrations into household teaspoons show that a single teaspoon of Cassia can contain several milligrams of coumarin — enough that daily intake of half to a full teaspoon could put some adults over the TDI depending on body weight and the Cassia variety ^{[6] [7]}.

4. Who is most at risk and when to prefer Ceylon

People with existing liver disease, those on hepatotoxic or blood‑thinning medications, children and smaller adults, and anyone consuming cinnamon daily or in supplement form are the main concern groups highlighted in the literature; for those consumers Ceylon’s ultra‑low coumarin profile is the safer choice ^{[6] [8]}. Public health guidance and food safety agencies explicitly recommend moderating Cassia intake and using Ceylon when cinnamon will be consumed frequently or in higher amounts ^{[8] [9]}.

5. Practicalities: identification, labeling and market realities

Powdered cinnamon in retail is seldom labeled by botanical source, making it hard to know whether a jar is Cassia or Ceylon without supplier transparency or testing, while stick appearance (single thick roll for Cassia vs. thin layered “cigarillo” rolls for Ceylon) can help identify whole‑bark sticks ^{[2] [7]}. Market dominance of cheaper Cassia means most cinnamon sold is likely to be Cassia unless declared otherwise, and coumarin content varies widely even within Cassia batches, which complicates simple rules of thumb ^{[4] [10]}.

6. Bottom line and recommended approach

Ceylon and Cassia both provide the culinary and some health benefits of cinnamon, but the safety difference centers on coumarin: Ceylon contains trace or negligible amounts while Cassia can contain hundreds to thousands of times more and therefore can exceed regulatory TDI limits with frequent use ^{[1] [2]}. For occasional seasoning most people need not worry, but anyone who consumes cinnamon daily, uses cinnamon supplements, has liver concerns, or is administering cinnamon to children should select Ceylon or limit Cassia intake and consult product labeling or suppliers when possible ^{[3] [6] [8]}.