Supplement analysis backed by scientific evidence · PT

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Limited evidenceBrain & cognition

Ginkgo Biloba

The largest and longest trial ever run on ginkgo found it did nothing: over a median 6.1 years in 3,069 older adults, EGb 761 did not slow cognitive decline at all. The dementia-treatment literature is inconsistent and dominated by small older trials. This is a popular supplement with genuinely poor evidence.

What the science says

  • Does not prevent cognitive decline in older adults Strong evidence

    The Ginkgo Evaluation of Memory (GEM) study randomized 3,069 adults aged 72-96 to 120 mg EGb 761 twice daily or placebo for a median 6.1 years. Annual rates of decline were essentially identical for memory, attention, visuospatial ability, language and executive function, with no difference on the 3MSE (p = 0.71) or ADAS-Cog (p = 0.97), and no benefit in any subgroup including mild cognitive impairment or APOE*E4 carriers. This is a large, well-powered, unambiguously negative trial.

  • Treating dementia and cognitive impairment Limited evidence

    A Cochrane review of 36 trials found most were small and under three months long. Of the four most recent trials to report, three found no difference from placebo and one reported very large effects. The reviewers concluded that evidence of predictable, clinically significant benefit is inconsistent and unreliable, and that publication bias cannot be excluded.

  • Tinnitus, claudication and other uses Limited evidence

    Ginkgo is widely promoted for tinnitus, intermittent claudication and vertigo. Trials in these areas are mostly small, older and inconsistent, and where larger trials exist the effect sizes shrink toward nothing, following the same pattern as the cognition literature.

Dosage & safety

Studied doseTrials used EGb 761 standardized to 24% flavone glycosides and 6% terpene lactones at 120-240 mg/day in divided doses. The GEM prevention trial used 120 mg twice daily for over 6 years, which is the dose and duration that failed. Cheaper non-standardized leaf powders were not what was tested.
SafetyGinkgo is well tolerated in trials, with no excess adverse events versus placebo in the Cochrane review, but it has antiplatelet activity and case reports link it to intracranial, ocular and post-surgical bleeding, particularly alongside aspirin, NSAIDs, warfarin or DOACs. Stop at least 1-2 weeks before surgery. It modulates several CYP enzymes (notably CYP2C19) and can lower levels of drugs such as efavirenz and some anticonvulsants; seizures have been reported and it is generally avoided in epilepsy. Raw or roasted ginkgo seeds contain ginkgotoxin (4'-O-methylpyridoxine) and can cause seizures and death, especially in children; never eat them. In Germany and several other countries standardized ginkgo extract is a registered medicine rather than a food supplement.

Scientific references

Where to buy

Natrol, Ginkgo Biloba, 60 Capsules

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