How we rate
“Strong” = several concordant meta-analyses or systematic reviews. “Moderate” = one synthesis, or several controlled trials. “Limited” = early trials only. The rating is about the quality of the studies, not about how useful the supplement is.
Ginkgo biloba
Ginkgo leaf extract, sold for memory. In healthy elderly people, it prevents neither dementia nor memory decline, even after six years; in patients already suffering from dementia, 240 mg per day slightly slows the decline.
Benefits
- In patients with cognitive impairment or dementia, slows the decline: in a meta-analysis of 9 trials on 2,561 patients, 240 mg per day of standardized EGb 761 extract stabilized or slowed cognitive, functional, and behavioral decline over 22 to 26 weeks
- In dementia with neuropsychiatric symptoms, a single dose of 240 mg per day improved cognitive and neuropsychiatric scores compared to placebo after 24 weeks
- In mild to severe dementia, 120 mg per day stabilized, and in a significant number of cases improved, cognitive performance and social functioning over 6 months to 1 year
- In peripheral artery disease of the legs (intermittent claudication), lengthens pain-free walking distance compared to placebo in a meta-analysis of eight trials, an effect that the authors consider modest
Precautions
The risk of bleeding is debated: a review of fifteen published cases describes hemorrhages occurring during ginkgo intake, often severe (eight intracranial hemorrhages), and considers a causal association possible; its authors request that individuals at risk of bleeding be informed. Controlled studies, however, find nothing: a meta-analysis of 18 trials on 1,985 adults shows no increased bleeding risk, 240 mg per day for 7 days altered none of the 29 measured coagulation parameters, and the extract did not enhance the effect of aspirin (500 mg per day) in 50 men, nor alter the action of warfarin in 12 healthy men. If you have a bleeding risk or take a blood-thinning medication, talk to your doctor. The limitations: in a prevention trial, 120 mg twice daily for a median duration of 6.1 years reduced neither dementia nor cognitive decline in people aged 75 and over; over five years, the GuidAge trial did not reduce the progression to Alzheimer's disease in elderly people complaining of their memory; a meta-analysis of two trials on nearly 6,000 people concludes that there is no convincing evidence for prevention. In healthy individuals over 60, six weeks improved neither memory nor attention. Against tinnitus, two trials, including one on 1,121 people, and a meta-analysis find nothing, even though one review notes an effect of EGb 761 when tinnitus is the main symptom. To prevent altitude sickness, nothing significant in a trial at 3,800 m nor in a meta-analysis of 451 people.
Recommended dosage
240 mg per day of standardized extract (EGb 761) in positive trials in patients with dementia; 120 mg twice daily in large prevention trials, which found nothing.
How to take it
- Who it is for: the only positive results in this profile concern patients already suffering from cognitive disorders or dementia, and leg artery disease. In healthy older adults, no trial in this profile finds an effect.
- Which form: positive trials use a precise standardized extract, EGb 761; a result obtained with it does not necessarily apply to another ginkgo powder.
- Dose: 240 mg per day in positive trials on dementia, in a single dose in one of them. In elderly patients, 160 or 240 mg per day changed nothing over 24 weeks in another trial.
- How long: benefits in patients appear over 22 to 26 weeks; a 2019 review mentions more than 24 weeks.
- What it does not do: neither prevention of dementia or Alzheimer's, nor better memory in healthy adults, nor an effect on tinnitus or altitude sickness, according to the trials in this profile.
- Timing and meals: no study in this profile compares morning to evening, nor intake during or between meals.
Did you know?
In a prevention trial, people aged 75 and over took 120 mg of ginkgo twice daily or a placebo for a median duration of 6.1 years: ginkgo did not reduce the number of dementia cases.
What the studies say
This systematic review and meta-analysis evaluated whether Ginkgo biloba extract (GBE) prevents acute mountain sickness (AMS), including seven study groups with 451 participants. Although GBE showed a trend toward AMS prophylaxis, the effect was not statistically significant. Current data are not sufficient to prove a significant effect, and larger studies are needed.
Tsai TY, Wang SH, Lee YK, Su YC. — BMJ open (2018) — View the source study
For information only: not a substitute for medical advice. Dietary supplements are not a replacement for a varied, balanced diet. Learn more