Ginkgo biloba is one of the world’s oldest living tree species. It’s been used medicinally for many centuries, and herbal ginkgo supplements are particularly popular in Europe and the US.
Ginkgo is promoted as a ‘smart’ drug to enhance the brain power of healthy people. But there's little evidence that it actually works.
- A systematic review published in 2007 looked at 15 randomised controlled clinical trials of ginkgo for cognitive function, carried out in healthy people aged under 60. The majority of studies used subjective ratings (self-reported improvement in memory, for example) to measure effect. Of these, only one of five single-dose studies and one of six longer-term studies reported any signifi cant positive results, and the review concluded there was no convincing evidence for a strong positive effect of ginkgo on any aspect of cognitive function in healthy young people. Findings from studies in older people with no cognitive impairment have been mixed.
- A large study involving more than 3000 participants is currently under way in the US. The Ginkgo Evaluation of Memory (GEM) study will evaluate whether long-term ginkgo use (120 mg, twice a day) will help prevent dementia in healthy elderly people, or those with mild cognitive impairment.
As a treatment for people with existing dementia or cognitive impairment, the evidence for ginkgo is mixed.
- A 2007 Cochrane review of the scientific literature included 35 studies, the majority being 12 weeks long. The daily dose was usually less than 200 mg/day, and all studies except one used a standardised ginkgo preparation known as EGb 761. Many of the trials received funding from the company that manufactures this preparation.
- Data from some trials at 12 weeks showed ginkgo to have a positive effect on cognition, but the effect was variable and shorter trials showed no benefit. The review concluded that the evidence for ginkgo being beneficial for people with cognitive impairment and dementia is inconsistent and unconvincing.
Commission E (a German government regulatory agency) approves the use of standardised ginkgo extract to treat dementia, but Alzheimer’s Australia thinks further research is needed before a definitive statement can be made about its effectiveness as a dementia treatment.
Going on the current evidence, there’s little to recommend the use of ginkgo for preventing dementia or improving memory or cognition if you’re healthy.