Fisetin is a naturally occurring flavonol, specifically a flavonoid polyphenol found in many fruits and vegetables including strawberries, apples, persimmons, onions, and cucumbers. Supplements with concentrated fisetin are commercially available. Although preclinical studies suggest that fisetin might increase cognitive performance and protect against Alzheimer's disease, no human research has been conducted.
Preclinical data suggests that fisetin may improve cognition or protect against Alzheimer’s disease, but there is no data suggesting that it will be effective in humans. Our search identified:
• 0 meta-analyses or systematic reviews
• 0 human clinical trials or observational studies
• Fewer than 10 preclinical studies suggesting a benefit to cognition or protection from Alzheimer's disease
Data from preclinical studies suggest that fisetin might strengthen the connections between brain cells and enhance memory in healthy rodents . Studies in animal models of Alzheimer's disease suggest fisetin may also lower levels of phosphorylated tau and aggregated beta-amyloid (i.e., the tangles and plaques common in patients with Alzheimer's) [2-4], lower levels of neuroinflammation , and prevent the development of memory deficits . Some studies also suggest that fisetin might be protective against stroke, which may lead to dementia . Despite this promising preclinical data, no studies have tested fisetin in humans.
No studies have examined fisetin in Alzheimer's patients, but some preclinical evidence (see above) suggests it could theoretically have a protective effect.
Fisetin consumed in the diet is safe, and fisetin supplements are commercially available with no reports that we could find for safety concerns or reported side effects. However, there is currently no scientific research in humans on whether supplemental doses of fisetin are safe, especially in the long term. Although fisetin is being researched as a potential treatment to protect from cancer, possible carcinogenic effects have been identified and the effects in humans have not been determined [10-13].
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.
No studies have examined the correct dosing of fisetin in human beings. It is estimated that a person would have to eat 37 strawberries every day to reach the doses used in animal studies. Fisetin is currently available over-the-counter as a supplement, generally in 100 mg tablets.
Salk Institute press release of treatment of Alzheimer's mouse model with fisetin
Article on fisetin and memory from Consumer Lab
Photo: Sri Kumar