This Popular Everyday Spice Might Affect How Your Body Processes Medications, Study Suggests

If cinnamon is a staple in your spice cabinet, welcome to the club. Whether it’s sprinkled atop oatmeal, mixed into baked goods, or whipped into a frothy coffee, this popular ingredient is clearly a fan favorite. However, before you indulge in this sweet spice, you should check your medications. 

A recent study published in Food Chemistry: Molecular Science found that high concentrations of cinnamon can cause dangerous interactions with some medications. Researchers examined how cinnamaldehyde—the strong-smelling compound that gives cinnamon its signature scent—is processed in the body by simulating digestion and using liver cell models to explore what happens once the compound is absorbed.

Interestingly, cinnamaldehyde is highly absorbable and quickly converts into cinnamic acid in the body, says Pamela Tambini, MD, an internal physician and medical director at Engage Wellness. “Higher doses, like concentrated supplements or oils, can activate a liver receptor called PXR, which plays a role in how our bodies break down many medications, and this means that cinnamon, especially in stronger forms, could affect how some drugs are metabolized,” she explains.

The study was conducted in a controlled laboratory, indicating that further research is necessary. However, the findings highlight a significant potential for drug interactions if cinnamon is consumed in large amounts, says Nicholas Church, MD, a family medicine physician and founder of Somerset Medical. 

Curious about which medications should not be taken with cinnamon? Keep reading for everything you need to know and tips on how to stay safe. 

How exactly does cinnamon interfere with medications?

According to the study, cinnamon can interfere with medications in two primary ways.  

First, cinnamon oil and cinnamic acid can activate receptors such as PXR and AhR, which regulate the production of liver enzymes responsible for drug metabolism, Church says. The activation of these receptors can then accelerate drug metabolism, potentially reducing the effectiveness of medications. 

Second, cinnamon oil and cinnamaldehyde can directly inhibit certain liver enzymes, specifically CYP2C9 and CYP1A2, which are involved in processing many common medications, such as warfarin, some diabetes medications, certain NSAIDs, and a few antidepressants, Church says. Depending on the situation, this could either slow down or speed up the rate at which drugs are cleared from the body.

That said, the issue is not so much the cinnamon spice in your kitchen — it’s when cinnamaldehyde enters your system in larger amounts, Tambini says. “The study found that cinnamaldehyde can ‘turn on’ the PXR receptor in the liver, and this receptor controls enzymes that help your body clear medications,” she explains. “If it’s activated, it could either speed up how quickly your body gets rid of a drug, making it less effective, or slow it down, which could raise the drug’s levels and side effects.”

In other words, cinnamon does not block medications — it subtly changes how your body processes them.

What kind of medications should be avoided when consuming cinnamon?

The study did not list specific medications to avoid when consuming cinnamon, but Tambini says drugs that rely on liver enzymes affected by PXR, such as CYP2C9 and CYP1A2, may be impacted. This is not an extensive list, nor are the medications to avoid mixing with cinnamon limited to these examples; this includes blood thinners, some antidepressants, certain pain relievers, and even some hormonal medications, Tambini says. 

“It’s likely fine if you have a cinnamon-flavored coffee or dessert now and then; however, if you’re taking cinnamon supplements or essential oils, it could be a different story, so always check with your doctor first,” Tambini says. “There is no ‘safe window,’ but a good rule of thumb is to avoid taking your meds within two to four hours of a high cinnamon intake to create a buffer.” 

When in doubt, Church recommends always consulting your doctor. You may not notice immediate symptoms, but regularly consuming high amounts of cinnamon could have a more lasting impact on drug metabolism. 

Do all forms of cinnamon interfere with medication?

No. Not all forms of cinnamon carry the same risk, Tambini says. “The concern is primarily with forms that contain a high concentration of cinnamaldehyde, like cinnamon oil or concentrated supplements.”

This is because ground cinnamon used in food contains significantly lower concentrations of active compounds compared to cinnamon oil or concentrated supplements. “Cinnamon oil, in particular, is much more potent and was the form most strongly linked to receptor activation and enzyme inhibition in the study,” Church says. “Regular culinary use of cinnamon in reasonable amounts is much less likely to cause problems.”

To break it down a bit more, cinnamon oil is the distilled essential oil that is highly concentrated in cinnamaldehyde and other active chemicals, Church says. Ground cinnamon, by contrast, is simply powdered bark that contains only small amounts of the essential oil, he explains. So, because cinnamon oil delivers a much higher dose of active compounds, it has a stronger effect on drug-metabolizing systems, while classic cinnamon used in cooking is far more diluted and less likely to interfere unless consumed in very large quantities.

Put differently, there is likely no need to entirely give up cinnamon. “For most people, cinnamon in food is completely safe and may even have health benefits, like helping regulate blood sugar or acting as an antioxidant (which promotes overall well-being and reduces the risk of chronic disease),” Tambini says. Again, the study mainly raises concerns about high-dose cinnamon supplements or concentrated oil products taken regularly.