Drinking cinnamon tea every day is generally safe, but the type of cinnamon you use matters more than you might expect. The key concern is a compound called coumarin, which can stress the liver over time. Cassia cinnamon, the variety sold in most grocery stores, contains up to 1% coumarin. Ceylon cinnamon contains roughly 0.004%, making it about 250 times lower in coumarin. If you’re drinking a daily cup, this distinction is the single most important thing to understand.
Why Cinnamon Type Is the Real Question
Most cinnamon sold in North America and Europe is cassia cinnamon. A single teaspoon of cassia contains roughly 5 mg of coumarin. The European Food Safety Authority set the tolerable daily intake for coumarin at 0.1 mg per kilogram of body weight, a level considered safe for lifelong daily consumption. For a 70 kg (154 lb) person, that’s 7 mg per day. One teaspoon of cassia in your tea already puts you close to that ceiling, and a heaping spoon or a second cup could push you over it.
Ceylon cinnamon, sometimes labeled “true cinnamon” or “Sri Lankan cinnamon,” contains only trace amounts of coumarin. You could drink several cups a day brewed with Ceylon sticks and stay well within safe limits. If daily cinnamon tea is something you want as a long-term habit, switching to Ceylon is the simplest way to remove the risk entirely. It’s slightly more expensive and has a milder, more complex flavor, but it’s widely available online and in specialty stores.
The Liver Risk Is Real but Preventable
Coumarin’s main concern in humans is liver damage. A review of 13 documented cases of cinnamon-induced liver injury found a pattern of severe damage: elevated bilirubin, dangerously low clotting function, and biopsy results showing widespread cell death across multiple areas of the liver. In one case, a 40-year-old man developed jaundice after four months of taking a supplement containing cinnamon. His liver enzymes spiked to more than 25 times the normal range, and recovery took weeks after he stopped.
These cases involved concentrated supplements or unusually high intake, not a single daily cup of tea. But they illustrate why the coumarin threshold exists. Your liver processes coumarin through a pathway that’s generally safe in humans, unlike in rodents where it causes tumors. Still, at high enough doses or in people with existing liver conditions, the compound can overwhelm even the human pathway. Germany issued a public warning about excessive cassia cinnamon intake back in 2006.
Potential Benefits of a Daily Cup
Cinnamon does more than flavor your tea. Its water-soluble compounds, the kind that dissolve when you steep a cinnamon stick, have shown meaningful effects on blood sugar regulation. In multiple clinical trials, cinnamon extracts at doses equivalent to what you’d get from tea reduced fasting blood glucose in people with type 2 diabetes, metabolic syndrome, and polycystic ovary syndrome (PCOS). One trial in women with PCOS found that eight weeks of a cinnamon extract improved insulin resistance to levels comparable to healthy controls.
The mechanism is interesting: cinnamon doesn’t increase insulin production. Instead, it makes the insulin your body already produces work more efficiently. In lab testing, water-based cinnamon extracts boosted insulin activity more than 20-fold, higher than any other compound tested at similar concentrations. Even in healthy men without blood sugar problems, consuming cinnamon for two weeks improved their insulin sensitivity and reduced blood sugar spikes after meals.
There’s also a modest effect on blood fats. A large meta-analysis found that cinnamon supplementation significantly reduced triglycerides by about 24 mg/dL and total cholesterol by about 14 mg/dL. It did not meaningfully change LDL (“bad”) cholesterol or HDL (“good”) cholesterol. These aren’t dramatic numbers, but as a bonus from something you’re drinking for enjoyment, they’re worth noting.
Antioxidant Content in Brewed Cinnamon
Cinnamon bark is packed with polyphenols, including proanthocyanidins, cinnamic acid, and several well-studied plant compounds like caffeic acid, gallic acid, and ferulic acid. An aqueous cinnamon extract was found to be roughly 56% polyphenols by weight. That’s an unusually high concentration for a single-ingredient tea.
There’s a catch, though. When these compounds hit your digestive system, about half of the polyphenols break down before your body can absorb them. The larger, more complex molecules (catechin polymers and long-chain proanthocyanidins) disappear almost entirely during digestion. What survives and reaches your bloodstream are the smaller compounds, primarily cinnamic acid and simpler phenolic acids. These remaining compounds still showed measurable anti-inflammatory and antioxidant effects in cell studies, reducing markers of oxidative stress when cells were exposed to inflammatory triggers.
Who Should Be Cautious
If you take blood-thinning medications, daily cinnamon tea deserves a conversation with your prescriber. Coumarin is chemically related to warfarin, and cassia cinnamon essentially adds a mild anticoagulant on top of your medication. A case report documented fatal gastrointestinal bleeding when cinnamon and ginger were taken alongside the blood thinner dabigatran. The combination increased the drug’s concentration in the blood while simultaneously adding coumarin’s own clot-preventing effect.
If you take diabetes medications, be aware that cinnamon can lower blood sugar independently. This isn’t dangerous on its own, but combined with insulin or glucose-lowering drugs, it could occasionally push your levels lower than expected.
For pregnant and breastfeeding women, the data is essentially nonexistent. No studies have measured cinnamon compound levels in breast milk or evaluated safety in nursing infants. The U.S. FDA considers Ceylon cinnamon “generally recognized as safe” as a food flavoring, which covers the amounts you’d use in cooking or a cup of tea. Supplemental doses are a different story, and there simply isn’t enough evidence to guide that decision.
How to Make It a Safe Daily Habit
Use Ceylon cinnamon if you plan to drink cinnamon tea every day for the long term. One stick or half a teaspoon of ground Ceylon cinnamon per cup keeps you well within safe coumarin limits, even with daily use. If you only have cassia, one cup a day brewed with a single stick is unlikely to cause problems for most people, but it leaves less margin for error, especially if you’re also eating cinnamon in other foods like oatmeal, baked goods, or smoothies.
Steep your cinnamon in boiling water for 10 to 15 minutes. Longer steeping extracts more beneficial compounds. If you’re using sticks rather than powder, you can reuse them once or twice before they lose potency. Adding a squeeze of lemon or a slice of ginger is common and won’t interfere with the beneficial properties.
For people with healthy livers who aren’t on blood thinners, a daily cup of cinnamon tea is a low-risk habit with plausible metabolic benefits. The one thing that turns it from safe to potentially harmful is using large amounts of cassia cinnamon day after day without realizing how much coumarin you’re accumulating.