ginkgo biloba

Ginkgo (Ginkgo biloba) is an ancient deciduous tree, often called a "living fossil." The most commonly used supplement form is the ginkgo leaf, usually as an extract, sold as capsules, tablets, liquid extracts, and teas.

According to NCCIH, there is no conclusive evidence that ginkgo is helpful for any health condition. A large NIH-funded trial, the Ginkgo Evaluation of Memory (GEM) study of more than 3,000 adults aged 75 and older, found no difference between ginkgo and placebo in the rates at which participants developed dementia of any type or Alzheimer's disease. NCCIH notes that ginkgo extract may have a modest benefit for dementia symptoms, particularly at relatively high doses, but the evidence is inconsistent, and that it is uncertain whether ginkgo supplements actually influence cognitive performance in healthy people, with much of the research being of low quality. For conditions such as anxiety, PMS, schizophrenia, and vertigo, NCCIH says a small amount of evidence suggests a possible benefit, but the overall evidence is not conclusive.

There is no established or NIH-endorsed standard dose; the GEM study used 240 mg per day of a standardized leaf extract, and other studies have used varying amounts. Because evidence of benefit is limited and ginkgo can interact with medications, talk to your doctor or pharmacist before starting it, including about the right product and whether it is appropriate for you.

NCCIH indicates that ginkgo leaf extract is generally well tolerated by most adults when taken orally, with mostly mild side effects. It may be unsafe to use during pregnancy, and little is known about its safety while breastfeeding. Fresh ginkgo seeds are toxic when eaten, and serious harms have occurred in people who consumed roasted seeds or raw plant material. Do not confuse the leaf extract with ginkgo seeds.

According to NCCIH, the most common side effects of ginkgo leaf extract are dizziness, gastrointestinal symptoms, and headache. More serious harms have been linked to ingesting ginkgo seeds or raw plant material rather than the standardized leaf extract.

NCCIH cautions that ginkgo may increase the risk of bleeding in people taking anticoagulant ("blood thinner") drugs such as warfarin, and it may interact with other medications. Tell your healthcare provider about all supplements and medicines you take, particularly if you have a bleeding disorder or have surgery planned.