Ginkgo Leaf Extract

Ginkgo leaf extract is made by dissolving compounds from the leaves of ginkgo, Ginkgo biloba, in acetone, which is then evaporated, leaving a dry extract. It is the most commonly used form of ginkgo, and medicines made with it are taken for age-related decline in mental abilities in adults with mild dementia.

Use in medicines

The dry extract is taken for age-related decline in mental abilities in adults with mild dementia; this use is backed by scientific publications covering at least 10 years. A doctor should be consulted if the symptoms do not improve after 3 months or get worse. How it works is not fully understood; it is thought to protect brain cells, either by regulating blood flow or by neutralising oxygen free radicals.

Health Canada's monograph goes further: licensed products for adults may claim to help thinking, memory and circulation in the limbs, at 80–240 mg a day of extract standardised for its flavonoid and terpene lactone content. Ginkgo extract may have a modest benefit for dementia symptoms, particularly at high doses, but the evidence is inconsistent; in three large studies in older adults it did not reduce the risk of dementia. Whether ginkgo affects thinking in healthy people is uncertain.

The World Health Organization's 1999 monograph describes a similar standardised extract, made with acetone and water, at 120–240 mg a day. It counts dementia symptoms, pain-free walking in poor leg circulation, and tinnitus and vertigo as indications supported by clinical data, and lists no traditional uses. The US National Center for Complementary and Integrative Health, in its current assessment, is more cautious about these benefits.

Safety

Ginkgo leaf extract is generally well tolerated; the most common side effects are dizziness, digestive symptoms and headache. Bleeding in the eye, nose, brain or gut has been reported. People who tend to bleed or take blood thinners should use the extract only after consulting a doctor.