Supplement: Ginkgo Biloba

What It Is

Ginkgo is an extract of the fan-shaped leaves of the ginkgo tree, one of the oldest tree species alive. Nearly all of the Western studies rely on a single well-defined preparation, a standardized leaf extract called EGb761, taken as a tablet somewhere between 120 and 240 mg a day. Most people meet it as a memory pill, and memory is the claim the trials have leaned on hardest.

Anatomy of the Practice

1In the small vessels

The extract mildly relaxes small blood vessels and makes red cells and platelets less sticky, so blood moves a little more easily through fine circulation. This is the property behind both the circulation research and the bleeding caution: the same effect that eases flow also thins the blood.

2In the tissues

The flavonoids in the leaf clear reactive oxygen and the terpene lactones block platelet-activating factor, a signaling molecule in clotting and inflammation. These were the mechanisms that made ginkgo a plausible candidate for protecting the aging brain and the inner ear.

3At the level of outcomes

A plausible mechanism is only a starting point. When the outcomes were measured, whether people developed dementia, whether memory held, or whether the ringing quieted, the mechanism did not translate into a large benefit.

How It Works

Everything ginkgo is sold to do traces back to one property: it improves circulation in fine vessels and eases oxidative stress in the tissue those vessels feed. That is genuine pharmacology. It is why the herb was once expected to help three organs at once: the brain as it ages, the inner ear, and the cardiovascular picture in the legs.

What a bottle contains matters as much as the biology. The prevention and dementia trials all leaned on the same standardized 240 mg preparation, so a loosely made jar that says nothing about standardization is simply not what was studied. That gap is much of why the supplement shelf and the trial record read so differently. The single most marketed use of all, quieting tinnitus, gets its own page tracing where that evidence lands.

What the Trials Found

Ginkgo arrived in the West carried by three things:

• a believable mechanism from its chemistry,
• decades of routine prescribing across Europe,
• and a run of encouraging early trials in memory clinics.

For years that was enough for the memory claim to be repeated as settled. Then prevention was tested directly, and the answer changed.

Two large, long trials went straight at prevention. The Ginkgo Evaluation of Memory study put 3,069 older adults on 240 mg a day for about six years. It recorded no drop in the rate of new dementia and no slowing of ordinary cognitive decline. GuidAge, run in France, gave 2,854 older adults who already had memory complaints the same extract for five years and found no reduction in progression to Alzheimer disease. Two prevention trials of this size and length landing on the same result is about as clear as this kind of question gets.

For holding off dementia in a healthy or worried older adult, ginkgo did not do it.

Drop below prevention and the ground shifts. In people who already carry a dementia diagnosis, a meta-analysis of the standardized 240 mg extract found modest gains in cognition and in the activities of daily living against placebo. A broader Cochrane review of the dementia literature was less impressed. It judged the overall evidence inconsistent and hard to lean on, with the steadier signals bunched at the higher 240 mg dose.

The two other marketed uses come out thinner. In tinnitus, a Cochrane review found the standardized extract did not clearly help people whose main trouble was the ringing itself. For the leg pain of intermittent claudication, an early meta-analysis logged a small gain in pain-free walking distance. A later Cochrane review that pooled more trials found no meaningful edge over placebo.

Vertigo is the one peripheral use with a firmer signal. In a 12-week randomized trial of 160 adults with vertigo, EGb 761 at 240 mg a day held even with betahistine, a standard prescription for dizziness. Clinicians rated 79 percent of the ginkgo group much or very much improved against 70 percent on the drug, with fewer side effects. This trial set EGb 761 against betahistine and ran no placebo arm. Its funding came from the extract's maker. What EGb 761 shows here is a tie with an accepted drug, not a win over a dummy pill.

Read together, the trials place ginkgo like this:

• It does not prevent dementia or sharpen a healthy memory.
• It gives a modest lift to the symptoms of dementia already present.
• It roughly matches a standard drug for vertigo, on the strength of one trial with no placebo arm.
• It does little to nothing dependable for tinnitus or the leg pain of claudication.

The Research & Studies

Everything here is based on the research we have collected and checked, sorted into groups and ordered with the strongest evidence first. Click any claim to open the studies behind it.

Cognition

Geen vermindering van dementie bij 240 mg per dag over zes jaar bij 3,069 oudere volwassenenStrong · no effect

In plain terms

Het nemen van een gestandaardiseerd ginkgo-extract elke dag gedurende ongeveer zes jaar verlaagde niet de kans op het ontwikkelen van dementie vergeleken met een neppil.

In detail

De Ginkgo Evaluation of Memory (GEM)-studie randomiseerde 3,069 zelfstandig wonende volwassenen van 75 jaar en ouder, met normale cognitie of milde cognitieve beperking bij aanvang, naar 120 mg gestandaardiseerd EGb761 twee keer per dag (240 mg totaal) of placebo, en volgde hen gedurende een mediaan van 6.1 jaar. Er was geen verschil in de frequentie van incidente dementie of Alzheimer-type dementie tussen de groepen. Dit is de grootste en langste preventiestudie van ginkgo.

Who this may not transfer to:Tested in adults 75 and older; it measured whether ginkgo prevents dementia, not whether it treats established dementia.

The study · 1

DeKosky 2008, JAMA · JAMA

Geheugen en denkvermogen daalden in hetzelfde tempo als placebo bij 3,069 oudere volwassenenStrong · no effect

In plain terms

De alledaagse achteruitgang in geheugen en denkvermogen die met de leeftijd gepaard gaat, vorderde in hetzelfde tempo of oudere volwassenen nu gestandaardiseerd ginkgo of een neppil namen.

In detail

Een vooraf gespecificeerde analyse van het GEM-cohort (3,069 volwassenen van 72 tot 96 jaar) vergeleek het tempo van cognitieve achteruitgang tussen 240 mg per dag gestandaardiseerd EGb761 en placebo over een batterij neuropsychologische tests. Er was geen verschil in het traject van enig cognitief domein over een mediaan van 6.1 jaar follow-up. Dit richt zich op de populaire bewering dat ginkgo een gezonde verouderende geest scherp houdt.

Who this may not transfer to:Adults 72 and older with healthy or mildly impaired cognition; it does not test younger users.

The study · 1

Snitz 2009, JAMA · JAMA

Niet minder Alzheimer-diagnoses over 5 jaar bij 2,854 volwassenen met geheugenklachtenModerate · no effect

In plain terms

Bij oudere volwassenen die geheugenproblemen hadden opgemerkt, verlaagden vijf jaar gestandaardiseerd ginkgo niet hoeveel er de ziekte van Alzheimer ontwikkelden.

In detail

De GuidAge-studie randomiseerde 2,854 Franse volwassenen van 70 jaar en ouder die spontaan geheugenklachten aan hun arts hadden gemeld, naar 120 mg gestandaardiseerd EGb761 twee keer per dag of placebo gedurende vijf jaar. Omzetting naar waarschijnlijke ziekte van Alzheimer verschilde niet significant tussen de groepen. Het resultaat bevestigt de GEM-preventiebevinding in een andere populatie en een ander land.

Who this may not transfer to:Older European adults who already noticed memory changes; it repeats the US prevention result in a different country.

The study · 1

Vellas 2012, Lancet Neurol · Lancet Neurol

Een kleine winst in cognitie en dagelijkse functie bij 240 mg per dag bij mensen die al dementie hebbenModerate

In plain terms

Voor mensen die al dementie hebben, gaf een gestandaardiseerd ginkgo-extract bij 240 mg per dag een bescheiden verbetering in denkvermogen en in het uitvoeren van dagelijkse taken vergeleken met een neppil.

In detail

Een systematische review en meta-analyse van negen gerandomiseerde, placebogecontroleerde studies (2,561 patiënten) van ginkgo bij cognitieve beperking en dementie vond dat EGb761 bij 240 mg per dag statistisch significante verbeteringen in cognitie en activiteiten van het dagelijks leven produceerde tegenover placebo, met de duidelijkere effecten bij de hogere dosis. Het voordeel is in het behandelen van symptomen van gevestigde dementie, een andere vraag dan de preventiestudies, en het effect is bescheiden.

Who this may not transfer to:Applies to people who already carry a dementia diagnosis, not to healthy adults hoping to prevent it.

The study · 1

Tan 2015, J Alzheimers Dis · J Alzheimers Dis

Gepoold over 36 studies is het dementie-bewijs inconsistent en onbetrouwbaarModerate · mixed

In plain terms

Wanneer alle ginkgo-dementie-studies samen worden gelezen, zijn de resultaten voldoende met elkaar in tegenspraak om een vaste conclusie niet te kunnen trekken.

In detail

Een Cochrane-systematische review van 36 studies van ginkgo bij cognitieve beperking en dementie concludeerde dat het bewijs inconsistent en onbetrouwbaar was, en merkte op dat terwijl sommige studies, met name bij hogere doses, voordelen rapporteerden, het geheel van het bewijs geen voorspelbaar klinisch effect ondersteunde. Dit is de reden om niet te vertrouwen op een enkele positieve meta-analyse.

Who this may not transfer to:A judgment on the whole trial base for cognitive impairment and dementia, not one study.

The study · 1

Birks 2009, Cochrane Database Syst Rev · Cochrane Database Syst Rev

Hearing And Tinnitus

Geen duidelijke verlichting wanneer oorsuizen de voornaamste klacht is, over 12 studiesModerate · no effect

In plain terms

Voor mensen wier voornaamste probleem oorsuizen is, verlaagde gestandaardiseerd ginkgo het oorsuizen of de daarmee gepaard gaande belasting niet duidelijk.

In detail

Een Cochrane-review van ginkgo voor oorsuizen poolde 12 gerandomiseerde, placebogecontroleerde studies (1,915 deelnemers) en vond geen duidelijk bewijs dat ginkgo de ernst van het oorsuizen vermindert wanneer oorsuizen het primaire presenterende symptoom is, en beoordeelde de zekerheid van het bewijs als laag. Sommige oudere studies waarbij oorsuizen een secundair symptoom was van een andere aandoening, zijn een afzonderlijke en zwakkere literatuur.

Who this may not transfer to:People whose main complaint is the ringing itself, not tinnitus that is a symptom of another condition.

The study · 1

Sereda 2022, Cochrane Database Syst Rev · Cochrane Database Syst Rev

Heart And Vascular

Geen betrouwbare winst in loopafstand over 14 gepoolde studiesModerate · no effect

In plain terms

Met meer studies toegevoegd hielp gestandaardiseerd ginkgo mensen met beenpijn door slechte circulatie niet betekenisvol verder te lopen dan een neppil deed.

In detail

Een Cochrane-review van ginkgo voor claudicatio intermittens poolde 14 gerandomiseerde, placebogecontroleerde studies (739 deelnemers) en concludeerde dat er geen bewijs was van een klinisch significant voordeel op de pijnvrije of maximale loopafstand. Deze latere, grotere review vervangt de eerdere positieve meta-analyse en wijst op geen betrouwbaar effect.

Who this may not transfer to:Adults with peripheral arterial disease; the larger, later pooling of the walking-distance trials.

The study · 1

Nicolai 2013, Cochrane Database Syst Rev · Cochrane Database Syst Rev

Ongeveer 112 ft (34 meter) meer pijnvrij lopen in een vroege pool van 8 studiesPreliminary

In plain terms

Bij mensen met beenpijn door slechte circulatie suggereerden vroege gepoolde studies dat ginkgo ze iets verder liet lopen voordat de pijn begon.

In detail

Een meta-analyse van 8 gerandomiseerde, placebogecontroleerde studies vond dat ginkgo een bescheiden, statistisch significante toename in pijnvrije loopafstand bij claudicatio intermittens produceerde tegenover placebo, een gewogen gemiddeld verschil van 112 ft (34 meter) (95%-BI 26 tot 43). De absolute winst was klein en de auteurs merkten op dat de studies bescheiden van omvang en kwaliteit waren, dus ze behandelden het als een voorlopig signaal dat later werk zou moeten bevestigen.

Who this may not transfer to:Adults with peripheral arterial disease; an early signal the larger later review did not confirm.

The study · 1

Pittler 2000, Am J Med · Am J Med

Vestibular

Kwam overeen met betahistine, een standaard vertigo-medicijn, over 12 weken in een trial met 160 patiëntenPreliminary

In plain terms

Voor vertigo hield gestandaardiseerde ginkgo stand tegenover betahistine, een veelgebruikt voorschrift voor duizeligheid. In een trial van 12 weken werkten de twee ongeveer even goed, en ginkgo veroorzaakte minder bijwerkingen.

In detail

Een gerandomiseerde, dubbelblinde trial (Sokolova 2014, Int J Otolaryngol) gaf 160 volwassenen met vertigo, gemiddelde leeftijd 58, ofwel EGb 761 met 240 mg per dag ofwel betahistine met 32 mg per dag gedurende 12 weken. Beide groepen verbeterden op alle uitkomstmaten, inclusief een vertigosymptoomschaal en algemene klinische indruk, zonder significant verschil tussen hen, en de winst van de ginkgo-groep was numeriek iets groter. Clinici beoordeelden 79% van de EGb 761-groep en 70% van de betahistine-groep als veel of zeer veel verbeterd, en EGb 761 veroorzaakte minder bijwerkingen. De beperking die telt, is dat de trial geen placebo-arm had, dus de verbetering in beide groepen omvat ook het natuurlijke afnemen van vertigo na verloop van tijd; wat het toont is dat ginkgo overeenkwam met een geaccepteerd geneesmiddel, niet dat het placebo versloeg.

Who this may not transfer to:Middle-aged and older adults with vertigo; the comparison is against an active drug, not placebo.

How to use it

Voor vertigo specifiek is gestandaardiseerde EGb 761 een van de beter onderbouwde ginkgotoepassingen, maar de oorzaak van de duizeligheid moet eerst worden beoordeeld, en de bloedingswaarschuwingen blijven van toepassing.

The study · 1

Sokolova 2014, Int J Otolaryngol · Int J Otolaryngol 2014;2014:682439

Ways to Do It

Match what you do to what you want. If the goal is protecting your memory for the years ahead, the strongest levers are not ginkgo, so the first rung is free. If the goal is trying a standardized extract for symptoms that already exist, the later rungs cover how to do that sensibly.

1

Protect the brain the ways that are backedFreeModerate

For keeping a mind sharp into later life, the best-supported levers are keeping blood pressure controlled, moving most days, sleeping well, staying socially and mentally engaged, and not smoking. None of these is ginkgo, and together they carry far more evidence than any supplement for brain aging.

2

What the trials tested is a standardized extract$Easy

The research record is built on the EGb761-type standardized extract, made to about 24 percent flavone glycosides and 6 percent terpene lactones. A product labeled only ginkgo, with no standardization stated, has not been studied to the same degree. An independent testing mark on the label is one more sign of what you are actually getting.

3

For existing memory symptoms, 240 mg a day, reviewed with a clinician$Easy

The modest benefit in people who already have dementia showed up at 240 mg a day of the standardized extract, taken for several weeks before judging it. Pair it with a proper medical assessment of the memory change, so the cause is found and tracked. It also carries the bleeding cautions below, so your prescriber should know you take it.

4

Set your expectations for prevention by the trialsFreeEasy

If you are healthy and hoping to hold off decline, the two large trials point away from ginkgo doing that. Spending the effort on the first rung will do more for the same goal.

5

Give it a fair trial length, then reassess$Easy

The trials that saw any symptom benefit ran for weeks to months, so a few days tells you nothing. If you try it, give it eight to twelve weeks at the standardized 240 mg dose, then judge with your prescriber whether anything has changed.

Go Deeper

• Tinnitus: the full evidence on what does and does not quiet the ringing.
• Omega-3 and fish oil: another supplement whose big trials rewrote a confident popular claim, a useful companion for reading past a headline.

The Chinese Medicine View

Chinese medicine and the Western supplement draw on different parts of the same tree. The pharmacy shelf sells the leaf; the classical Chinese drug is the seed inside the fruit, Bai Guo, and it is put to a completely different job.

Bai Guo has a long standing in the materia medica. It is classed as astringent and used chiefly to bind the Lung and quiet wheezing. That places it among the herbs for cough and asthma, with no classical tie to memory or circulation. The seed appears in the classic wheezing formula Ding Chuan Tang, and it also handles leukorrhea and frequent urination. The tradition doses it carefully, treating the raw seed as toxic and allowing only small, prepared amounts. The leaf, by contrast, is a fairly recent arrival in Chinese practice and carries none of the deep classical record the seed does.

The two accounts never meet, and forcing one to explain the other would be invention. One tradition reasoned about a seed that astringes the Lung and must be handled carefully because it is toxic raw. Western labs studied a leaf extract for the brain and circulation and found the memory claim mostly hollow. Same plant, different part, different purpose.

Cautions For This Practice

Extra restraint

Everything to be aware of is here, in one place. This practice suits most healthy people; a few situations call for real care.

Serious spontaneous bleeding in 15 reported cases, especially with blood thinners

A case report and systematic review of the literature identified 15 published cases of bleeding associated with ginkgo, including 8 episodes of intracranial hemorrhage and bleeding into the eye, several in people also taking antiplatelet or anticoagulant drugs. The mechanism is ginkgo inhibition of platelet-activating factor, which reduces platelet aggregation. Controlled trials of platelet function have been less consistent, but the case evidence and the mechanism together warrant caution around blood thinners and surgery.Bent 2005, J Gen Intern Med

Bleeding, blood thinners and surgery

Ginkgo makes platelets less sticky and blocks platelet-activating factor, so it thins the blood. Documented cases of spontaneous bleeding, including into the eye and the brain, have occurred in people taking it. Take it seriously if you use warfarin, aspirin, clopidogrel or any other blood thinner. The same holds if you have a bleeding disorder, or surgery or dental work coming up. Tell your prescriber. Stopping ginkgo one to two weeks before planned surgery is standard.

The raw seed and seizures

The traditional Chinese drug is the seed, Bai Guo. The raw or undercooked seed contains a compound that can trigger seizures when eaten in quantity, with children most at risk. This warns against eating raw ginkgo seeds. It does not apply to the standardized leaf extract, which is processed to remove most of that compound. The plant and the word are the same even though the products differ, so the seed caution often gets misapplied to the supplement.

Product quality and adulteration

Ginkgo is among the more frequently adulterated botanicals on the market, sometimes bulked with cheaper flavonoids so a lab test looks right. A product that does not state EGb761-type standardization, or carry an independent testing mark, may not be what the trials studied or what the label claims. This is the quality variable most within your control.

Allergy and ginkgolic acids

Poorly processed extracts can retain ginkgolic acids, relatives of the compounds in poison ivy that cause allergic skin and mucous-membrane reactions. People sensitive to those plants, and anyone who reacts to a ginkgo product, should avoid it. A properly standardized extract keeps these acids low.

Pregnancy, and when a memory change needs a doctor

There is little safety data in pregnancy, and the blood-thinning effect is a further reason to avoid ginkgo then. Separately, a new or worsening memory problem should be assessed medically; the treatable causes are worth finding, and ginkgo did not prevent dementia in the trials that tested it.

Start slow, be smart, read the research, and consult a professional if you have any concerns. This is here to inform your choice, not make it for you.

Common Questions

Should I take ginkgo for my memory?

For a healthy person, the evidence runs the other way. The Ginkgo Evaluation of Memory and GuidAge trials looked for less dementia and slower decline in older adults and found neither. The reputation held for years; the prevention result behind the memory claim came back empty. Trying ginkgo anyway is a fair personal call, made with that result in view.

If the trials were negative, why is ginkgo still sold for memory?

Because a reputation outlives the studies that test it. Ginkgo's name was made over years of routine European use, long before the two big prevention trials existed. Marketing carried it forward on the strength of real leaf chemistry, which still makes the story sound plausible on a shelf. The claim on the label simply outran what later trials could show.

Does ginkgo help with dizziness or vertigo?

Yes, and it is ginkgo's best-supported use outside the brain. In one company-funded trial it kept pace with betahistine, a standard dizziness drug, though that trial had no placebo group to beat. So it looks about as good as an accepted treatment, on thin evidence. Vertigo has many causes, so have yours checked before treating it, and mind the bleeding cautions above if you take a blood thinner.

Is ginkgo safe to take with blood thinners?

Treat this as the main safety question with ginkgo. It reduces platelet stickiness, so on top of warfarin, aspirin or clopidogrel it can push bleeding risk higher, and case reports include serious spontaneous bleeds. The same concern applies before surgery or dental work, where stopping one to two weeks ahead is routine. If you use any blood thinner or have a bleeding disorder, clear ginkgo with your prescriber before starting.