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

No reduction in dementia on 240 mg a day over six years in 3,069 older adultsStrong · no effect

In plain terms

Taking a standardized ginkgo extract every day for about six years did not lower the chance of developing dementia compared with a dummy pill.

In detail

The Ginkgo Evaluation of Memory (GEM) study randomized 3,069 community-dwelling adults aged 75 and older, with normal cognition or mild cognitive impairment at entry, to 120 mg of standardized EGb761 twice daily (240 mg total) or placebo, and followed them a median of 6.1 years. There was no difference in the rate of incident dementia or of Alzheimer-type dementia between groups. This is the largest and longest prevention trial of 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

Memory and thinking declined at the same pace as placebo in 3,069 older adultsStrong · no effect

In plain terms

The everyday decline in memory and thinking that comes with age went at the same pace whether older adults took standardized ginkgo or a dummy pill.

In detail

A pre-specified analysis of the GEM cohort (3,069 adults aged 72 to 96) compared the rate of cognitive decline between 240 mg a day of standardized EGb761 and placebo across a battery of neuropsychological tests. There was no difference in the trajectory of any cognitive domain over a median 6.1 years of follow-up. This addresses the popular claim that ginkgo keeps a healthy aging mind sharp.

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

No fewer Alzheimer's diagnoses over 5 years in 2,854 adults with memory complaintsModerate · no effect

In plain terms

In older adults who had noticed memory problems, five years of standardized ginkgo did not reduce how many went on to develop Alzheimer disease.

In detail

The GuidAge trial randomized 2,854 French adults aged 70 and older who had spontaneously reported memory complaints to their doctor to 120 mg of standardized EGb761 twice daily or placebo for five years. Conversion to probable Alzheimer disease did not differ significantly between groups. The result corroborates the GEM prevention finding in a different population and country.

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

A small gain in cognition and daily function at 240 mg a day in people who already have dementiaModerate

In plain terms

For people who already have dementia, a standardized ginkgo extract at 240 mg a day gave a modest improvement in thinking and in managing daily tasks compared with a dummy pill.

In detail

A systematic review and meta-analysis pooling nine randomized placebo-controlled trials (2,561 patients) of ginkgo in cognitive impairment and dementia found that EGb761 at 240 mg a day produced statistically significant improvements in cognition and in activities of daily living relative to placebo, with the clearer effects at the higher dose. The benefit is in treating symptoms of established dementia, a different question from the prevention trials, and the effect is modest.

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

Pooled across 36 trials, the dementia evidence is inconsistent and unreliableModerate · mixed

In plain terms

When all the ginkgo dementia trials are read together, the results disagree with one another enough that a firm conclusion cannot be drawn.

In detail

A Cochrane systematic review pooling 36 trials of ginkgo for cognitive impairment and dementia concluded that the evidence was inconsistent and unreliable, noting that while some trials, particularly at higher doses, reported benefits, the body of evidence as a whole did not support a predictable clinical effect. This is the reason not to rely on any single positive meta-analysis.

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

No clear relief when ringing in the ears is the main complaint, across 12 trialsModerate · no effect

In plain terms

For people whose main problem is ringing in the ears, standardized ginkgo did not clearly reduce the ringing or the distress it causes.

In detail

A Cochrane review of ginkgo for tinnitus pooled 12 randomized placebo-controlled trials (1,915 participants) and found no clear evidence that ginkgo reduces tinnitus severity when tinnitus is the primary presenting symptom, rating the certainty of the evidence as low. Some older trials in which tinnitus was a secondary symptom of another condition are a separate and weaker literature.

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

No dependable gain in walking distance across 14 pooled trialsModerate · no effect

In plain terms

When more trials were added, standardized ginkgo did not meaningfully help people with poor-circulation leg pain walk further than a dummy pill did.

In detail

Une revue Cochrane du ginkgo pour la claudication intermittente a regroupé 14 essais randomisés contrôlés contre placebo (739 participants) et a conclu qu'il n'y avait pas de preuve d'un bénéfice cliniquement significatif sur la distance de marche sans douleur ou la distance maximale. Cette revue ultérieure et plus large supplante la méta-analyse positive antérieure et pointe vers l'absence d'effet fiable.

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

About 112 feet (34 meters) more pain-free walking in an early pool of 8 trialsPreliminary

In plain terms

In people with leg pain from poor circulation, early pooled trials suggested ginkgo let them walk a little further before the pain started.

In detail

A meta-analysis of 8 randomized placebo-controlled trials found ginkgo produced a modest, statistically significant increase in pain-free walking distance in intermittent claudication compared with placebo, a weighted mean difference of 112 feet (34 meters) (95% CI 26 to 43). The absolute gain was small and the authors noted the trials were modest in size and quality, so they treated it as a preliminary signal that later work would need to confirm.

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

Matched betahistine, a standard vertigo drug, over 12 weeks in a 160-patient trialPreliminary

In plain terms

For vertigo, standardized ginkgo held its own against betahistine, a common prescription for dizziness. In a 12-week trial the two worked about equally, and ginkgo caused fewer side effects.

In detail

A randomized, double-blind trial (Sokolova 2014, Int J Otolaryngol) gave 160 adults with vertigo, mean age 58, either EGb 761 at 240 mg a day or betahistine at 32 mg a day for 12 weeks. Both groups improved on all outcome measures, including a vertigo symptom scale and clinician global impression, with no significant difference between them, and the ginkgo group's gains were numerically slightly larger. Clinicians rated 79% of the EGb 761 group and 70% of the betahistine group much or very much improved, and EGb 761 caused fewer adverse events. The limit that matters is that the trial had no placebo arm, so the improvement in both groups also includes the natural settling of vertigo over time; what it shows is that ginkgo matched an accepted drug, not that it beat placebo.

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

For vertigo specifically, standardized EGb 761 is one of the better-supported ginkgo uses, but the cause of the dizziness should be assessed first, and the bleeding cautions still apply.

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.

Saignements spontanés graves dans 15 cas rapportés, surtout en association avec des anticoagulants

Un cas clinique et une revue systématique de la littérature ont identifié 15 cas publiés de saignement associé au ginkgo, dont 8 épisodes d'hémorragie intracrânienne et de saignement oculaire, plusieurs chez des personnes prenant également des médicaments antiplaquettaires ou anticoagulants. Le mécanisme est l'inhibition par le ginkgo du facteur d'activation plaquettaire, qui réduit l'agrégation plaquettaire. Les essais contrôlés sur la fonction plaquettaire ont été moins cohérents, mais les cas cliniques et le mécanisme ensemble justifient la prudence vis-à-vis des anticoagulants et de la chirurgie.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.