Ginkgo

botanicalbilobalide

What is it

Ginkgo (Ginkgo biloba) is a unique tree species native to China, with a fossil record dating back over 200 million years. Its fan-shaped leaves are used in herbal medicine, primarily as standardized extracts containing flavone glycosides (typically 24 percent) and terpene lactones (typically 6 percent).

How it works

Ginkgo's main proposed effects involve cerebral blood flow, platelet activity, and antioxidant function. Flavone glycosides and terpene lactones (including ginkgolide B) appear to inhibit platelet-activating factor (PAF), modestly improve microcirculation, and scavenge free radicals. Improved cerebral perfusion is the popular mechanistic story for ginkgo's traditional reputation in cognition and dementia. Clinical evidence has been mixed. The Ginkgo Evaluation of Memory (GEM) trial, the largest controlled study (3,069 older adults followed for 6 years), found no significant effect on incidence of dementia. Smaller and shorter trials in patients with existing mild cognitive impairment or early Alzheimer's have shown modest benefits with the standardized extract EGb 761 at 240 mg per day. The Cochrane review on ginkgo for dementia concluded the evidence is inconsistent and unreliable. Ginkgo also has more consistent evidence for tinnitus (mixed results) and intermittent claudication (modest improvement in walking distance).

Evidence for 6 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Dementia and Alzheimer's disease

Grade C

Moderate evidence

Evidence is mixed. Smaller trials with EGb 761 at 240 mg/day have shown modest cognitive improvements in mild to moderate Alzheimer's, but the large GEM trial in 3,069 older adults found no effect on dementia incidence. A Cochrane review concluded evidence is inconsistent.

Tinnitus

Grade C

Moderate evidence

Trials of ginkgo 120 to 240 mg/day for tinnitus have shown mixed results. Some find modest improvement; others find none. Effects are smaller than for other tinnitus management approaches.

Intermittent claudication (peripheral artery disease)

Grade C

Moderate evidence

Meta-analyses suggest 120 to 320 mg/day ginkgo modestly improves pain-free walking distance in adults with intermittent claudication. Effects are smaller than cilostazol but with fewer side effects.

Vertigo

Grade C

Moderate evidence

Trials in vestibular vertigo have shown ginkgo (160 mg/day) modestly improves symptoms over 12 weeks. Effect comparable to betahistine in one head-to-head trial.

Cognitive function in healthy adults

Grade D

Mixed evidence

Most controlled trials in cognitively normal adults find no meaningful cognitive enhancement from ginkgo. Marketing for memory and focus is not well supported by evidence in healthy populations.

Macular degeneration

Grade D

Mixed evidence

Limited evidence suggests ginkgo may slightly improve visual function in early macular degeneration. Not standard care.

3 commercial forms

EGb 761 (standardized ginkgo extract)

Standardized to 24 percent flavone glycosides and 6 percent terpene lactones; the form used in most positive trials.

The reference standardized extract. Tebonin and Tanakan are common brand names internationally.

Generic standardized ginkgo (24/6)

Matches EGb 761 specification; quality varies by manufacturer.

Most consumer products. Look for the 24/6 standardization marker and certifications for quality.

Whole leaf ginkgo (unstandardized)

Variable bioactive content; may contain higher ginkgolic acid levels.

Less reliable and potentially more allergenic. Standardized extracts are preferred.

Dosage

Typical doses are 120 to 240 mg per day of standardized extract (EGb 761 or equivalent), divided into 2 or 3 doses. Cognitive and dementia trials have used 120 to 240 mg/day; tinnitus trials similar; intermittent claudication 120 to 320 mg/day. Effects typically take 4 to 6 weeks to plateau.

When and how to take it

Take 60 to 120 mg standardized ginkgo extract two to three times daily with or without food. Effects build over 4 to 6 weeks; this is not an acute supplement. Morning and midday dosing is common to avoid any sleep disruption, though ginkgo is not significantly stimulating. Consistent daily use matters more than precise timing. Allow at least 6 weeks before evaluating benefit for cognitive or circulation outcomes.

Safety

Ginkgo is generally well tolerated at typical doses. Common side effects include mild GI upset, headache, dizziness, and rash. The most clinically important safety issue is bleeding risk: ginkgo inhibits platelet-activating factor and has been associated with case reports of intracranial hemorrhage, particularly when combined with anticoagulants or antiplatelet drugs. Stop 1 to 2 weeks before surgery. The ginkgolic acids in raw ginkgo leaves and seeds can be hepatotoxic and allergenic; standardized extracts limit them to under 5 parts per million. Avoid raw ginkgo seeds, which contain compounds that can cause seizures. No formal Tolerable Upper Intake Level has been established. Long-term safety beyond 6 years has not been well characterized.

Who should be cautious

Avoid with bleeding disorders or while on anticoagulants/antiplatelet drugs. Stop 1 to 2 weeks before surgery. Avoid with seizure disorders. Use cautiously on antidepressants, diabetes medications, or hepatically metabolized drugs. Pregnancy and breastfeeding should avoid due to limited safety data. Do not use raw ginkgo seeds.

Interactions

Ginkgo significantly raises bleeding risk when combined with anticoagulants (warfarin, heparin, DOACs) or antiplatelet drugs (aspirin, clopidogrel, NSAIDs). Multiple case reports of intracranial bleeding exist. May enhance the effects of antidepressants (theoretical serotonin syndrome with MAOIs). May reduce the effectiveness of anticonvulsants (carbamazepine, phenytoin, valproic acid) by lowering blood levels. May lower blood sugar, compounding diabetes medications. Affects CYP enzymes (CYP3A4, CYP2C19), potentially altering many drug levels.

Frequently asked questions

Will ginkgo improve my memory?⌄

In healthy adults with normal cognition, controlled trials generally find no significant memory improvement. In adults with mild cognitive impairment or early dementia, smaller trials have shown modest benefits, but the largest long-term trial (GEM) found no effect on dementia incidence.

Is ginkgo safe to take with aspirin or fish oil?⌄

Caution is warranted. Both ginkgo and aspirin have antiplatelet effects, and case reports describe intracranial bleeding with the combination. Fish oil at high doses adds further antiplatelet effect. If you are on any anticoagulant or antiplatelet regimen, discuss with your prescriber.

How long until ginkgo works?⌄

Effects build over 4 to 6 weeks of consistent daily use. Don't expect acute effects from a single dose. If you don't see meaningful improvement after 12 weeks at 240 mg/day, it likely isn't going to.

Can I eat ginkgo nuts?⌄

Cooked ginkgo seeds are eaten in some Asian cuisines but should be limited to small amounts (a few seeds per day) because they contain 4-O-methylpyridoxine, which can cause seizures at higher amounts. Raw seeds are more dangerous. Ginkgo supplements use leaf extract, not seed.

Does ginkgo really help with tinnitus?⌄

Trial results are mixed. Some show modest improvement, others show no effect. If you try it, give it 12 weeks at 120 to 240 mg/day before judging. Many users find it doesn't help dramatically, but it has a clean safety profile if you have no bleeding concerns.

References

  • Wikidata: Ginkgo biloba — Wikidata link

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Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you're pregnant, breastfeeding, on medications, or managing a chronic condition.