Ginkgo Biloba EGb 761: Why the Dementia Evidence Hasn’t Translated

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Ginkgo biloba is one of the top-selling supplements in the world and one of the most-studied herbal extracts in modern medicine. The question is not whether it has been studied but what the studies have actually shown — and the answer is more modest than two decades of marketing have suggested.

The GEM Trial and Dementia Prevention

The Ginkgo Evaluation of Memory (GEM) study — the largest trial of ginkgo ever conducted — randomised 3,069 older adults to EGb 761 240 mg/day or placebo over a median 6.1 years. Primary endpoint: incidence of dementia. Result: no benefit. Ginkgo did not reduce dementia incidence, cognitive decline, or Alzheimer’s diagnosis compared to placebo. This result fundamentally shifted the evidence base against ginkgo for dementia prevention in healthy older adults.

Mild Cognitive Impairment and Symptomatic Dementia

For patients who already have mild cognitive impairment or symptomatic dementia, the evidence is slightly more favourable. A 2015 Cochrane review found EGb 761 240 mg/day produced small improvements in cognition and activities of daily living in dementia patients compared to placebo over 22–26 weeks. Effect sizes are smaller than acetylcholinesterase inhibitors.

Tinnitus and Peripheral Vascular

Ginkgo has been tested extensively in tinnitus, with meta-analyses producing mixed or negative results. For intermittent claudication (peripheral arterial disease), a 2013 Cochrane review found ginkgo extended pain-free walking distance modestly compared to placebo — meaningful but smaller than exercise therapy.

The EGb 761 Preparation Is Specific

Almost all positive evidence refers specifically to EGb 761 (Tanakan, Tebonin) — a proprietary extract standardised to 24% flavonoid glycosides and 6% terpene lactones, with ginkgolic acids <5 ppm. Generic ginkgo products vary enormously in specification and cannot be assumed to replicate trial results.

Safety

Ginkgo has clinically meaningful antiplatelet effects. Case reports document post-surgical bleeding, subdural haematoma, and interactions with warfarin, DOACs, and aspirin. Stop 2 weeks before surgery. Also interacts with anticonvulsants (may lower seizure threshold) and with SSRIs through MAO modulation. At appropriate doses in healthy users, ginkgo is generally safe; the interactions matter more than the isolated toxicity.