Ginkgo extract is made from the leaves of the Ginkgo biloba tree and is one of the most widely used herbal medicines in the world. It works through two main mechanisms: it boosts nitric oxide production in the lining of your blood vessels, which relaxes small vessels and improves microcirculation, and its terpene compounds (ginkgolides) block platelet-activating factor, which has a mild blood-thinning effect. The flavonoids in the leaf are also strong antioxidants that protect brain and vascular tissue from oxidative stress. This combination is why ginkgo has been used for decades in Europe as a prescription drug for age-related memory complaints, ringing in the ears, dizziness and vertigo, and circulation-limited leg pain when walking.
Most people take it hoping for a memory or focus boost. That's not really where the evidence sits. In healthy adults with normal cognition, ginkgo doesn't reliably do anything measurable for memory, attention, or executive function. Where it does have real evidence is in older adults with mild cognitive complaints, in vertigo and tinnitus, in PMS and perimenopausal symptoms in women, and in peripheral circulation issues. If you fall into one of those buckets, it's worth an 8-12 week trial. If you don't, you're probably better off spending your money elsewhere.
Two things to know upfront before considering ginkgo. First, the mild blood-thinning effect means it doesn't mix well with anticoagulants (warfarin, DOACs), antiplatelets (aspirin, clopidogrel), or NSAIDs. If you're on any of those, talk to whoever manages your medication before starting, and stop ginkgo 1-2 weeks before any planned surgery. Second, because it lowers vascular tone via nitric oxide, be cautious if you're already on multiple vasodilators (nitrates, sildenafil/tadalafil, certain blood pressure medications) or run naturally low blood pressure. Ginkgo on its own doesn't drop blood pressure in healthy people, but stacking vasodilatory effects can.
One last practical note: the trial evidence is almost entirely on EGb 761, a German pharmaceutical-grade extract standardised to 24% flavonoid glycosides and 6% terpene lactones. Cheap generic ginkgo varies wildly in active content and the studies below don't apply to it. Use a product that explicitly states EGb 761 or matches the 24/6 standardisation.
Deep-dive
Ginkgo biloba is one of the oldest tree species on the planet, and its leaves contain two pharmacologically distinct groups of compounds that act in different ways. The flavonoids, mainly quercetin, kaempferol, and isorhamnetin, are antioxidants that scavenge free radicals and protect endothelial cells. The terpene lactones, made up of ginkgolides A, B, C, and bilobalide, are unique to ginkgo and act as platelet-activating factor (PAF) antagonists, which is the mechanistic basis for both the circulation effects and the bleeding concerns. Bilobalide also has neuroprotective and anti-inflammatory effects in its own right. Animal and in vitro work suggests the two groups work synergistically and that the natural 4:1 ratio in EGb 761 is more effective than either fraction alone.
Vascular and circulatory effects. Ginkgo's most consistent mechanism is on the vasculature. It induces eNOS expression and increases nitric oxide availability in endothelial cells, antagonises endothelin-1, and improves microcirculation. A small MR perfusion study in nine healthy older men found measurable increases in cerebral blood flow after 4 weeks of 60 mg twice daily. This is the basis for its use in intermittent claudication (circulation-limited leg pain when walking) and for its modest effects on vertigo and tinnitus of vascular origin.
Cognition in healthy adults. This is where the marketing and the evidence diverge sharply. A 2012 meta-analysis of randomised trials in healthy people, covering 1,132 participants for memory, 534 for executive function, and 910 for attention, found effect sizes essentially at zero across all three domains. Dose, duration, age, and total intake did not change the result. If you are cognitively healthy and looking for a nootropic edge, ginkgo is not it.
Cognition in older adults and dementia. This is where the picture is more interesting but also more contested. Meta-analyses of EGb 761 at 240 mg/day in mild-to-moderate dementia show modest but statistically significant improvements in cognition, activities of daily living, and global function over 22-26 weeks, with a tolerability profile similar to placebo. The two largest dementia-prevention trials, the GEM study (3,069 adults aged 72-96 followed for a median of 6.1 years) and the GuidAge trial in France, both found that ginkgo did not prevent dementia in older adults with normal cognition or mild cognitive impairment, and did not slow the rate of cognitive decline. So the read is: ginkgo can produce a small symptomatic benefit in people who already have mild-to-moderate dementia, but it does not prevent dementia in healthy older adults and it is not a substitute for proper diagnosis and treatment.
Tinnitus, vertigo, and claudication. Ginkgo at 240 mg/day for 12 weeks performed similarly to betahistine (a prescription drug for vertigo) in a head-to-head trial, with roughly 79% of patients showing meaningful improvement on the EGb 761 arm. The tinnitus evidence is mixed. Smaller trials suggest benefit, but the largest study (1,121 participants on 50 mg three times daily) found no effect. For intermittent claudication, meta-analyses show modest gains in pain-free walking distance, with the higher 240 mg dose outperforming 120 mg in head-to-head work.
Mood and sexual function. A 2009 PMS trial in 85 women found ginkgo reduced PMS symptom severity by about 24% versus 9% on placebo across one cycle. For postmenopausal women, a 30-day trial of 120-240 mg/day reported improvements in sexual desire, pleasure, and orgasm scores. The picture in antidepressant-induced sexual dysfunction is less convincing, with systematic reviews finding no consistent benefit on top of SSRIs.
Women. Beyond the menopause and PMS work above, a randomised crossover trial directly comparing men and women on 120 and 240 mg of ginkgo found that ginkgo improved executive function (Stroop and Berg tasks) in women but not in men. The proposed mechanism was that women had a stronger cardiovascular reactivity to cognitive load on placebo, and ginkgo blunted that reactivity. This is a small study and should not be over-interpreted, but it is a meaningful sex-specific signal that the bulk of the negative healthy-adult cognition meta-analyses (which pool both sexes) may have washed out. If there is a population of healthy adults where ginkgo plausibly does something for cognition, women under cognitive demand are the best current candidate.
Pharmacokinetics. The terpene lactones (ginkgolides A and B, bilobalide) are absorbed at 70-90% bioavailability after oral dosing of EGb 761. The flavonoid glycosides have much lower direct bioavailability and are largely metabolised by gut bacteria into smaller absorbable compounds. Peak plasma concentrations occur within 1-3 hours, half-life is 2-4 hours for the flavonols and around 4-6 hours for ginkgolides. The active compounds clear within 24 hours, which is why ginkgo is dosed two or three times daily rather than once.
Limitations of the evidence. Most positive trials use EGb 761 specifically. Generic ginkgo extracts vary widely in actual flavonoid and terpene content, and the literature on cheap, non-standardised products is thin and unreliable. Many of the dementia trials are funded by the manufacturer of EGb 761. The dementia-prevention trials in healthy adults were uniformly negative. And the bleeding case reports, while individually weak, are numerous enough to take seriously when ginkgo is combined with anticoagulants or before surgery.
Dosage:
- Standard dose: 120-240 mg/day of standardised EGb 761 (24% flavonoid glycosides, 6% terpene lactones), split into 2-3 doses with meals. 240 mg/day is the dose used in most dementia, vertigo, and claudication trials and tends to outperform 120 mg/day on head-to-head comparisons. 120 mg/day is the lower end and what most over-the-counter products supply
- Form matters more than dose. Look for products that explicitly state EGb 761 or the 24/6 standardisation. Generic ginkgo without standardisation has unpredictable potency and the trial evidence does not apply. Ginkgolic acid content should be under 5 ppm (the European Pharmacopoeia limit), since ginkgolic acids are a contact allergen and potential genotoxin
- Timing: Take with food to reduce GI upset. Split doses (e.g. 120 mg morning and evening) keep blood levels steadier given the short half-life
- Duration to assess effect: Allow at least 8-12 weeks before deciding whether it is doing anything. Ginkgo is not acute, the trials that show benefit run for months. If you have not noticed anything by 12 weeks at 240 mg/day, stop
- Women in PMS or perimenopause: 40 mg three times daily from mid-cycle through to day 5 of the next cycle is the protocol used in the PMS trial. For perimenopausal sexual function, 120-240 mg/day continuously was used
- Older adults with mild cognitive complaints: 240 mg/day is the dose with the strongest dementia-trial signal. This is a symptomatic intervention, not a preventive one, and it is not a substitute for a proper cognitive workup
- Stop 1-2 weeks before any planned surgery because of the bleeding risk concern
- Do not exceed 240 mg/day. Higher doses do not produce more benefit and increase the risk of bleeding, GI upset, and (with non-standardised or seed-containing products) ginkgotoxin exposure
Here's what you can expect:
If you are a healthy young or middle-aged adult taking ginkgo for sharper thinking, you will probably notice nothing. The meta-analyses on this population are flat. There is a possible exception for women under cognitive demand, where one trial found executive function gains, but it would be dishonest to promise that.
If you are an older adult with mild cognitive complaints, or you are taking it for tinnitus or vertigo, expect any change to be modest and to take 8-12 weeks to appear. Patients in the dementia trials describe slightly steadier daily function and slightly less mental fog, not a sudden lift. About 70-80% of patients in vertigo trials report meaningful symptom reduction.
For circulation-limited leg pain (intermittent claudication), expect a small increase in pain-free walking distance over 12-24 weeks. Useful at the margin if you are already doing the basics (walking, smoking cessation, statins where indicated), not a replacement for them.
For PMS or perimenopausal symptoms, the effect is real but modest, and it sits in the same broad bucket as several other plant-based interventions. Worth a 2-3 cycle trial.
There is no acute hit. If you take ginkgo today, you will not feel anything today. This is not the compound class for that.
Side effects & risks:
- GI upset, headache, mild dizziness are the most common side effects in trials, usually mild and self-limiting. Splitting the dose and taking with food helps
- Bleeding risk is the main safety concern. Ginkgolide B is a platelet-activating factor antagonist, which is the mechanistic worry. Controlled studies of EGb 761 in healthy volunteers have not shown meaningful effects on coagulation parameters, but a large VA database analysis found a 38% increased bleeding risk when ginkgo was taken with warfarin (HR 1.38). The honest read: ginkgo alone in healthy people is probably fine for bleeding, but combining it with warfarin, DOACs, clopidogrel, aspirin, NSAIDs, or any other antiplatelet or anticoagulant raises real concerns. Stop ginkgo 1-2 weeks before any planned surgery, dental extraction, or invasive procedure
- Seizure risk with non-standardised products. Ginkgo seeds (and to a lesser extent leaves) contain ginkgotoxin (4'-O-methylpyridoxine), a vitamin B6 antagonist that can lower seizure threshold by depleting GABA synthesis. Pharmaceutical-grade EGb 761 has very low ginkgotoxin content and seizure case reports are rare in standardised-extract users, but anyone with epilepsy or on antiepileptic medication should avoid ginkgo entirely, including standardised extracts. Do not consume raw ginkgo seeds
- Drug interactions through CYP induction. Ginkgo induces CYP2B6, CYP3A4, and the drug efflux pump P-gp at the level of the liver and intestine, which can lower blood levels of drugs metabolised by these enzymes. The list is long and includes some statins, calcium channel blockers, certain HIV protease inhibitors, and many more. If you are on chronic prescription medication, check for interactions before starting
- Allergic reactions can occur, particularly to products with high ginkgolic acid content. Skin rashes are the typical presentation
- Blood pressure: Ginkgo at 240 mg/day for 6 years in the GEM trial of 3,069 elderly adults had no effect on blood pressure or incidence of hypertension. The cardiovascular signal in ginkgo is on microcirculation and endothelial function, not on systemic BP
- Pregnancy and breastfeeding: Avoid. The PAF-antagonist activity raises a theoretical concern for placental and intrapartum bleeding, and there is no good safety data
- Conditions to avoid ginkgo entirely: Active or recent bleeding, planned surgery within 2 weeks, epilepsy or seizure disorder, on warfarin or DOACs without specialist sign-off, pregnancy, breastfeeding
Blood markers
CBC and platelet count, baseline, if you plan to use ginkgo for more than a few months or alongside any other compound that affects platelet function (fish oil at high doses, garlic extract, vitamin E at high doses, NSAIDs).
PT/INR, baseline and at 4-6 weeks, only if you are on warfarin or any other coumarin anticoagulant. Ideally have this conversation with whoever manages the anticoagulation rather than starting ginkgo independently.
Liver function (ALT, AST), baseline, given that ginkgo induces CYP enzymes and may interact with hepatically-metabolised drugs. Useful to have a reference point if you are on chronic medication.
For most people taking standardised EGb 761 at 120-240 mg/day with no other anticoagulants and no chronic medications, no specific bloodwork is needed. The people who genuinely need baseline labs are those on anticoagulants or antiplatelets, anyone with a personal or family history of bleeding disorders, anyone with epilepsy, and older adults already on a complex medication regimen.
Sold as a dietary supplement in most countries and as a prescription medicine (EGb 761, brand names Tebonin and Tanakan) in much of Europe.
Made with Bullet