The spice cinnamon is extracted from the inner bark of tropical evergreen trees from the genus Cinnamomum. Cinnamon contains several potentially active compounds including cinnamaldehyde, coumarin, and tannins, some of which can enter the brain and may reduce oxidative stress or inflammation. While preclinical studies suggest that cinnamon could improve brain health and possibly prevent dementia, the evidence for its benefit has yet to be verified in humans. It is generally considered safe, though higher doses carry some risks.
There have been several clinical trials on cinnamon, though none specifically looked at its impact on brain function. Our search identified:
• 0 meta-analyses or systematic reviews
• 0 clinical trials in humans looking at effects on cognitive function or cognitive decline
• Multiple preclinical studies
Research on the effects of cinnamon on the human brain is extremely limited. No human studies support the idea that cinnamon can delay or prevent dementia. Preclinical studies have shown that cinnamon may have the potential to protect against the plaques and tangles that are characteristic of Alzheimer's disease [2-6] as well as against a substance thought to be associated with advanced age and disease  but it is unknown whether cinnamon can achieve these effects in humans or even reach the brain in sufficient quantities. Small clinical trials suggest that cinnamon may improve metabolic health and patients with type II diabetes, a condition which can be associated with an increased risk of Alzheimer's disease, [8-12]. However, the effects and the research quality are too inconsistent to achieve predictable results in patients .
No human research has reported whether cinnamon or related compounds can benefit patients with dementia or mild cognitive impairment.
Cinnamon is safe for general consumption but allergic reactions are possible and consuming large amounts at once can carry serious risks, such as inflammation of the lungs . Cassia cinnamon, the kind most commonly found in grocery stores and tested in clinical trials, contains coumarin, which can cause liver toxicity. Thus, some experts warn against prolonged dosages exceeding 2 grams of cassia cinnamon per day for adults weighing 130 pounds or more . In short clinical trials, however, up to 6 grams per day of cassia cinnamon have not elicited significant adverse effects. Diabetics should be particularly cautious since cinnamon can lower blood sugar and thus interact with insulin and other treatments. No available evidence shows that cinnamon supplements are safe during pregnancy .
NOTE: This is not a comprehensive safety evaluation or complete list of potentially harmful drug interactions. It is important to discuss safety issues with your physician before taking any new supplement or medication.
Cinnamon is widely available whole or ground for use as a spice. A daily dose of up to 6 grams of cassia cinnamon has been tested in short clinical trials with no serious adverse effects. In clinical trials for blood sugar control for diabetics, higher doses did not necessarily increase benefits. Instead, higher doses may increase the risk of side effects.
The National Center for Complementary and Alternative Medicine
Drugs.com Cinnamon Guide