Coumarin in Cinnamon: What Published Testing Actually Shows (Ceylon vs. Cassia)

If you've ever read that "too much cinnamon is bad for your liver," the study behind that claim is real — and it's almost certainly not about the cinnamon you're picturing. It's about coumarin, a compound found at wildly different levels depending on which of the two unrelated plants your "cinnamon" actually came from.

Two spices, one name

Cassia and Ceylon are both sold as "cinnamon" in the US, but they're different species — Cinnamomum cassia and Cinnamomum verum. Cassia is what's in almost every grocery-store cinnamon jar and most cinnamon rolls, cereals, and baked goods. Ceylon, grown only in Sri Lanka, is a smaller, lighter-colored, more floral spice that's genuinely uncommon in US kitchens.

The difference that matters most isn't flavor. It's coumarin — a naturally occurring compound both species contain, but at very different concentrations.

What independent testing has measured

A peer-reviewed assessment of ground cinnamon sold on the Czech retail market tested 60 samples across 12 Cassia-cinnamon brands using HPLC (high-performance liquid chromatography, the standard lab method for this measurement). Mean coumarin content came out to roughly 3,856 mg/kg, with individual brand means ranging from about 2,650 to 7,017 mg/kg. A Ceylon cinnamon sample sourced directly from a Sri Lankan plantation, tested by the same method, came back below the instrument's detection limit.

That pattern — Cassia consistently measurable in the thousands of mg/kg, Ceylon consistently near or below detection — shows up across the published testing on this topic, not just one study.

Why regulators care about the number

The European Food Safety Authority (EFSA) has set a tolerable daily intake for coumarin of 0.1 mg per kilogram of body weight per day, based on evidence of liver stress at higher regular intake. Germany's Federal Institute for Risk Assessment (BfR) has gone further, specifically recommending Ceylon over Cassia for anyone eating cinnamon daily.

Run the numbers on an average adult (about 70 kg / 154 lb): the daily coumarin limit works out to roughly 7 mg. Using the Czech study's mean Cassia concentration, a single teaspoon of ground Cassia cinnamon (about 2.6 g) contains somewhere in the neighborhood of 10 mg of coumarin — over the daily limit from one teaspoon, before counting anything else you ate that day. A teaspoon of Ceylon, at non-detectable levels, contributes essentially none.

To be clear about what this isn't: it's not a claim that Cassia cinnamon is dangerous in occasional use, and it's not a medical claim about what coumarin does in your specific body. It's a straightforward unit-conversion exercise using a regulator's own published limit and a peer-reviewed lab measurement — the kind of math worth doing yourself before deciding how much cinnamon to put in your morning oatmeal, every single day, for years.

Where this leaves the "just use cinnamon" advice

Most health content presents "cinnamon" as one ingredient. The coumarin data says that's the wrong frame if you're using it daily rather than occasionally. Species, not brand or price, is the variable that actually changes the chemistry.

Our Ceylon cinnamon is single-origin from partner farms in Sri Lanka's Kandy and Matale districts, shipped as whole quills — the same species tested at non-detectable coumarin levels in the studies above. We're building toward publishing independent, per-batch lab verification for every spice we sell through our Open-Batch system; that program isn't live for this SKU yet, so use the published research above, not a Raman Rasa test result, as the basis for anything you decide here.

FAQ

Is all "cinnamon" the same species?

No. Most cinnamon sold in the US — including most grocery-store powder, cinnamon rolls, and cereal — is Cassia (Cinnamomum cassia). True Ceylon cinnamon (Cinnamomum verum) is a different species, grown only in Sri Lanka, and is much less common in US retail.

How much coumarin does Cassia cinnamon actually contain?

A peer-reviewed test of 60 retail Cassia samples found a mean of roughly 3,856 mg/kg, with individual brand averages ranging from about 2,650 to 7,017 mg/kg. Ceylon cinnamon tested from the same study came back below the detection limit.

What's EFSA's safety threshold for coumarin?

The European Food Safety Authority set a tolerable daily intake of 0.1 mg per kg of body weight per day. For a 70 kg adult, that's about 7 mg/day — a threshold a single teaspoon of Cassia cinnamon can approach or exceed based on published concentration data.

Does this mean I should never use Cassia cinnamon?

The concern scales with frequency and dose, not occasional use. Germany's BfR specifically recommends Ceylon over Cassia for people who eat cinnamon daily — the same body doesn't flag occasional Cassia use in typical recipe amounts as a similar concern.

Is Raman Rasa's cinnamon lab-tested for coumarin?

We're building toward independent, per-batch lab verification for every spice we sell, published through our Open-Batch system. That verification isn't live for this product yet — this article is based on independently published third-party research, not a Raman Rasa test result.

Pre-order our single-origin Ceylon cinnamon — sourced from Sri Lanka's Kandy and Matale districts, shipped as whole quills.