Ginkgo biloba

What is ginkgo biloba?

Ginkgo biloba is one of the oldest living tree species, sometimes called a living fossil. Its fan-shaped leaves are used to make standardized extracts, the most studied of which is EGb 761, typically standardized to about 24% flavonoid glycosides and 6% terpene lactones. Ginkgo seeds have been used in traditional Chinese medicine, but the modern supplement is made from the leaves.

Ginkgo became one of the best-selling supplements in the world on the promise of improving memory and circulation, and it is still widely used for brain health.

What the research says

Ginkgo has been put to the test in large, well-designed trials, and the results have been largely disappointing for prevention. The NCCIH reports that ginkgo did not reduce the risk of dementia in three large studies of older adults. In the Ginkgo Evaluation of Memory (GEM) study, more than 3,000 people aged 75 or older took ginkgo or placebo for a median of about six years, and rates of dementia and Alzheimer’s disease did not differ between the groups.

The NCCIH notes that ginkgo extract may modestly help symptoms in people who already have dementia, especially at higher doses, but the evidence is inconsistent. For healthy people looking to sharpen memory, the evidence is uncertain and much of it is low quality.

How it’s used in supplements

Most trials have used 120 to 240 mg per day of standardized leaf extract, divided into two or three doses. Effects, when seen, generally took weeks to appear. A product that does not state its ginkgo amount or standardization cannot be compared with this research.

According to the NCCIH, ginkgo leaf extract is likely safe for most adults in moderate amounts. Common side effects include headache, dizziness and stomach upset. More importantly, ginkgo may increase bleeding risk, especially in people taking anticoagulants such as warfarin, and it may interact with other medications. It may be unsafe during pregnancy, where it could contribute to early labor or extra bleeding near delivery, and its safety during breastfeeding is not well studied. Raw or roasted ginkgo seeds are toxic and should not be eaten.

Anyone planning surgery should stop ginkgo in advance and tell their surgeon. People taking antidepressants, antiseizure medicines or diabetes drugs should check with a doctor or pharmacist first, since interactions have been reported or suspected.

Bottom line: ginkgo is a reasonable thing to discuss with a doctor if you are curious, but large trials do not support it as a way to protect memory in healthy older adults.