For thousands of years, leaves from the Ginkgo biloba tree have been a common treatment in Chinese medicine. In the U.S., many take ginkgo supplements in the belief that they will improve memory and sharpen thinking.
Why do people take ginkgo?
Ginkgo improves blood flow to the brain and acts as an antioxidant. These effects may translate into some benefits for certain medical problems, but the results have been mixed.
Some studies have found that in healthy people, ginkgo might modestly boost memory and cognitive speed. Other studies have not found a benefit.
Several ginkgo studies have shown that it can help with memory problems caused by dementia or Alzheimer’s disease. It seems to help prevent the progression of dementia symptoms, especially if the dementia is thought to be the result of atherosclerotic vascular disease. It does not seem to prevent dementia or Alzheimer’s, however.
There's good evidence that ginkgo might ease leg pain caused by clogged arteries. It might also help with some other circulation problems. In addition, ginkgo may relieve PMS symptoms, like breast tenderness and mood changes.
Researchers have studied ginkgo for many other conditions, including ADHD, depression and other psychological conditions, multiple sclerosis, and tinnitus from a vascular origin. Some people are also using ginkgo to prevent high altitude sickness, though studies have not yet established that it’s effective for that. Many uses of ginkgo show promise, but more research needs to be done.
How much ginkgo should you take?
There is no standard dose of ginkgo biloba supplements. However, in medical studies, almost all clinical trials have used a standardized extract of ginkgo, standardized to 24% flavone glycosides and 6% terpene lactones. A common dose in people with dementia is 40 milligrams of that extract three times daily. For improving cognitive function in healthy people, studies have used between 120 milligrams to 240 milligrams of the extract daily.
Can you get ginkgo naturally from foods?
The only source of ginkgo is the ginkgo tree. Most ginkgo supplements are derived from the leaves. Ginkgo seeds can be dangerous, especially when raw.
What are the risks of taking ginkgo?
- Side effects. Ginkgo leaf supplements are generally safe. In some people, they can cause headache, dizziness, heart palpitations, nausea, gas, and diarrhea. Allergies to ginkgo can trigger rashes or more serious effects.
- Risks. If you have a bleeding disorder, or are planning surgery, talk to your doctor before using ginkgo. Don't take ginkgo if you have any medical conditions -- especially diabetes, epilepsy, or fertility problems -- unless your doctor recommends it. Do not eat untreated parts of the ginkgo plant. Uncooked ginkgo seeds can cause seizures and death.
- Interactions. If you take any medicines or supplements regularly, talk to your doctor before you start using ginkgo supplements. They could interact with blood thinners, aspirin, NSAID painkillers, antiplatelet drugs, anticonvulsants, antidepressants, diabetes medicines, drugs that affect the liver and supplements like garlic, saw palmetto, St. John's wort, and yohimbe. Ginkgo might reduce the effectiveness of electroconvulsive therapy (ECT.)
Given the potential risks, ginkgo is not recommended for children or for women who are pregnant or breastfeeding.