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Ingredients / Ginkgo biloba
Limited evidence overall 16 articles · reviewed 2 Sep 2026

Ginkgo biloba

Ginkgo biloba L. leaf extract

The best-funded failure in the cognitive supplement category. Two large prevention trials ran for years and found nothing.

What the evidence supports

Limited Dementia prevention GEM and GuidAge, both large and long, were null. This is about as settled as supplement evidence gets.
Limited Memory in healthy adults Small positive trials have not replicated at scale.
Moderate Symptomatic dementia treatment European trials of EGb 761 at 240 mg/day report small cognitive-scale improvements; independent replication is weaker.
Limited Tinnitus Repeatedly tested, inconsistently positive, mostly in low-quality trials.
Dose used in trials
120–240 mg

per day of a standardised leaf extract (24% flavone glycosides, 6% terpene lactones) for 6 months or more.

Safety
Bleeding signal

Case reports of bleeding, especially alongside anticoagulants. Raw ginkgo seeds are toxic.

Ask a doctor first if
Four cases

Anticoagulants or antiplatelets, seizure disorder, pregnancy, or surgery within two weeks.

The trials, individually

Open any one for sample size, funding and what it actually measured.

GEM · 3,069 older adults · dementia
Randomised, 240 mg/day, median 6.1 years. No reduction in all-cause dementia or Alzheimer incidence. Large, independent and clean — the reason this ingredient is graded limited.
GuidAge · 2,854 adults · Alzheimer
Five years in adults reporting memory complaints. No effect on progression to Alzheimer disease.
Meta-analysis · EGb 761 · dementia treatment
Pooled 240 mg/day trials show small improvements on cognitive scales in diagnosed dementia. Most were conducted or funded by the extract manufacturer.

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