Cinnamon Compound Linked to Reduced Efficacy of Prescription Drugs

According to a new study conducted by researchers at the University of Mississippi, the primary compound in cinnamon, cinnamaldehyde, has the potential to reduce the efficacy of certain prescription medications. The study, announced on August 21, 2025, found that while adding a small amount of cinnamon to food or drinks is unlikely to cause any problems, consuming cinnamon in high doses as a supplement could lead to complications.

"Health concerns could arise if excessive amounts of supplements are consumed without the knowledge of health care provider or prescriber of the medications," explained Shabana Khan, a principal scientist involved in the study. The researchers discovered that cinnamaldehyde can activate receptors in the body that actually break down certain medicines, potentially making them less effective.

The study also noted that cinnamon oil, typically used in cooking and toiletries, poses no risk. However, cinnamon bark, especially the cheaper Cassia cinnamon variety from China, has a higher potential to cause medication-related issues. "True cinnamon from Sri Lanka carries a lower risk due to its reduced coumarin content," said Amar Chittiboyina, the study's co-author and associate director of the National Center for Natural Products Research.

Consumers who regularly consume significant amounts of cinnamon or have concerns about their cinnamon intake should speak to their healthcare providers before continuing to use the spice, the researchers advised. Anyone relying on medications to manage chronic conditions should be particularly cautious when using cinnamon or any other supplements, as they could negatively interact with their prescribed treatments.