Pharmacopoeial Material
Dry leaves of Ginkgo biloba L. French Pharmacopoeia List A. The EMA has issued a formal herbal monograph (EMA/HMPC/321097/2012) covering standardised leaf extract for cognitive and vascular indications. [58]
EMA Monograph · Multiple Systematic Reviews · 70 References
Biological Overview
Ginkgo biloba is the sole surviving species of the order Ginkgoales — a lineage with a fossil record extending 270 million years, making it one of the oldest living plant species on Earth. Its standardised leaf extract EGb 761 is one of the most thoroughly studied phytomedicines in clinical research, with a unique dual mechanism of action combining neuroprotection through antioxidant and anti-ischaemic pathways, and vascular protection through PAF antagonism and vasodilation.
Key ActivesGinkgolides A/B/C, Bilobalide, Flavonoid Glycosides
Primary TargetsPAF Receptors · GABA-A · NO Pathway · Antioxidant
EMA StatusEU Herbal Monograph — Ginkgo biloba L., folium
Living Fossil270 million years · Sole survivor of Ginkgoales order
Botanical Classification
Taxonomy & Identification
- Latin Name
- Ginkgo biloba L.
- Family
- Ginkgoaceae
- Common Names
- Ginkgo, Maidenhair Tree, Arbre aux quarante écus
- Chinese Name
- Yín Xìng (銀杏) — Silver Apricot
- Parts Used
- Leaves (dry)
- ⚠ Toxic Parts
- Seeds/fruits — contain toxic alkaloids
- Origin
- China — cultivated near temples; relict species
- Longevity
- Up to 4,000 years (Far East records)
Ethnobotany
History & Tradition
Ginkgo biloba survived the Hiroshima atomic bomb explosion in 1945 — trees growing within 1–2 km of the epicentre resprouted the following spring while all other vegetation was destroyed. This remarkable resilience is consistent with its extraordinary longevity as a species: ginkgo survived mass extinction events that eliminated most of its contemporaries, earning it the title of "living fossil." [1]
Chinese traditional medicine used the seeds (ovules), not the leaves, for at least 5,000 years — documented in the Shen-nung pen ts'ao ching treatise. The leaves were not medicinalised until European botanical and pharmacological research in the 20th century identified their unique phytochemical profile. German botanist Engelbert Kaëmpfer (1651–1715) was the first European to describe the tree and assigned it its name from the Japanese "gin kyo."
The modern phytomedicine era began in the 1960s when German researchers developed the standardised EGb 761 extract, enabling reproducible clinical trials. Today ginkgo is one of the three best-selling phytomedicines globally and the only plant-derived treatment to have been directly compared head-to-head with approved Alzheimer's disease drugs in randomised clinical trials.
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Hiroshima, 1945 — Sole Survivor
Six ginkgo trees within 1–2 km of the Hiroshima atomic bomb epicentre survived and resprouted in spring 1946. They still stand today. This extraordinary radioresistance is attributed to the tree's potent antioxidant and DNA-protective phytochemical ensemble — the same properties now studied for neuroprotection.
Key Historical Milestones
~3000 BCE
First medicinal use recorded in China (Shen-nung treatise) — seeds used
17th C
Introduced to France by botanist Pétigny — "arbre aux quarante écus" (40 gold coins per specimen)
1945
Only trees to survive Hiroshima atomic bomb — resprouted spring 1946
1960s
EGb 761 standardised extract developed in Germany — enables reproducible clinical trials
2006
Head-to-head RCT vs donepezil: EGb 761 shows comparable efficacy in Alzheimer's dementia
2024
Ginkgo + Rhodiola combination reviewed for post-COVID cognitive impairment and fatigue
The Standardised Extract
EGb 761 — Deep Dive
The single most important concept in ginkgo supplementation — and the one most supplement labels obscure. EGb 761 is not a brand; it is a precisely defined extract specification that all evidence-based clinical trials have used.
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What EGb 761 Specifies
EGb 761 is a dry extract of Ginkgo biloba leaves concentrated at a 35–67:1 ratio from raw leaf material. It must contain 22–27% flavonoid glycosides (primarily quercetin, kaempferol, and isorhamnetin glycosides), 5–7% terpene lactones (2.8–3.4% ginkgolides A, B and C combined with 2.6–3.2% bilobalide), and — critically — less than 5 ppm ginkgolic acid. This last specification is the primary safety control. Without it, ginkgolic acid contamination can reach levels thousands of times the recommended maximum.
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Why Plain Ginkgo Tea Does Not Work
The Wikiphyto source states explicitly: ginkgo leaf tisane (tea) is not effective because ginkgolides are not water-soluble. This means any aqueous preparation — tea, infusion, or water-based extract — is missing the terpene lactone fraction entirely. Since ginkgolides are the primary PAF antagonists and anti-ischaemic agents, a plain leaf tea delivers only the flavonoid fraction and not the full pharmacological profile. Standardised hydroalcoholic extract (EGb 761 or equivalent) is the only form with clinical trial evidence behind it.
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Ginkgolic Acid Contamination — Critical Safety Issue
Some commercial ginkgo products contain 80,000 times the recommended maximum of ginkgolic acid.
Ginkgolic acids are anacardic acid derivatives that are potent contact allergens and potential genotoxins. The German recommendation sets the maximum daily intake at 0.6 micrograms. Testing of 20 commercial products found that a consumer could ingest up to 48,000 micrograms of ginkgolic acid per day from some products — 80,000 times the recommended limit. The EGb 761 specification requires less than 5 ppm ginkgolic acid; without this specification, no safety guarantee exists.
Practical guidance: Only purchase ginkgo products standardised to contain less than 5 ppm ginkgolic acid, with third-party verification. This specification should be stated on the label or available via certificate of analysis. Generic "ginkgo leaf extract" without ginkgolic acid specification is potentially unsafe at any dose.
Pharmaceutical Preparations
Parts Used & Available Forms
Only the leaves are medicinal. Seeds and fruits contain toxic alkaloids and must never be consumed.
Available Forms
- ▸ Standardised dry extract — Tanakan® and generics (EGb 761)
- ▸ Mother tincture (teinture-mère) of leaves
- ▸ EPS (standardised plant extract)
- ✗ Leaf tisane/tea — NOT effective (ginkgolides insoluble in water)
Toxic Parts Warning
Products containing ginkgo fruits or seeds must not be consumed — they contain toxic alkaloids. Only standardised leaf extracts (EGb 761) have documented safety and efficacy. Ginkgolic acid content must be below 5 ppm in any preparation intended for medicinal use.
Clinical Dosimetry
Dosages
All dosages refer to EGb 761 or equivalent standardised extracts (22–27% flavonoid glycosides, 5–7% terpene lactones, <5 ppm ginkgolic acid).
Phytochemistry
Composition
The leaf contains a structurally unique ensemble of terpene lactones found nowhere else in the plant kingdom, alongside a rich flavonoid fraction. Synergy between these two classes produces broader neuroprotective and vascular effects than either fraction alone. [56]
Terpene Lactones — Unique to Ginkgo
Ginkgolides A, B, C, J, MDiterpenes — hexacyclic structures with 20 carbon atoms, three γ-lactone rings, two hydroxyl groups and a tert-butyl group (exceptionally rare in natural compounds); 0.02–0.2% in leaves [2]; potent PAF antagonists — ginkgolide B the first natural PAF inhibitor identified
Principal
BilobalideSesquiterpene — 0.02–0.06% in leaves; neuroprotective, anti-ischaemic, vasoactive; increases cerebral glucose and oxygen uptake; activates cortical metabolism; GABA-A receptor modulator
Neuroprotective
Pentanorginkgolide, DihydroatlantoneMinor sesquiterpene derivatives — contribute to terpene lactone fraction synergy
Minor
Why Ginkgolides Are Unique
Ginkgolides possess a structural motif — the tert-butyl group in a natural hexacyclic diterpene — that is effectively unique in the plant kingdom. Ginkgolide B was the first naturally occurring PAF (Platelet Activating Factor) antagonist ever identified, making ginkgo the original model for an entire class of anti-inflammatory drug targets.
Flavonoids & Other Constituents
Flavonol GlycosidesGlucosides, rhamnosides, rutinosides and p-coumaric esters of quercetin and kaempferol; luteolin — primary antioxidant fraction; 22–27% in EGb 761; protect neurons against NO-induced toxicity [12]
22–27% EGb
BiflavonoidsAmentoflavone, bilobetin, ginkgetin, isoginkgetin, sciadopitysin, apigenin — antiviral activity (ginkgetin inhibits influenza sialidase); apigenin blocks oestrogen synthesis step
Antiviral
Proanthocyanidols (Prodelphinidols)Oligomeric proanthocyanidins — antioxidant, vascular protective activity; reinforce capillary resistance
Antioxidant
Ginkgolic Acids (Anacardic Acids)⚠ Allergenic — must be below 5 ppm in standardised preparations; some commercial products contain up to 80,000× the recommended safe level; potential genotoxin at high doses
⚠ Limit <5ppm
Organic Acids & Other6-Hydroxy-kynurenic acid, shikimic acid; sterols, aliphatic ketones, cyclitols, polysaccharides
Present
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Neuroprotective & Anti-Ischaemic
Ginkgolides A and B, and bilobalide protect neurons from ischaemic brain injury. [3] Multiple studies confirm EGb 761 attenuates ischaemic reduction in hippocampal proteins including hippocalcin, [4] parvalbumin, [5] PEA-15, [6] p70S6 kinase, [7] and Bad-Bcl-XL interaction. [8] Protects motoneurones after neurological damage. [15]
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Cognitive Enhancement
Improves cognitive function in healthy volunteers, [9] dementia patients, [10] and older adults. [51] Improves hippocampal synaptic plasticity in aged rats. [13] Pharmacological and biochemical effects on learning, memory consolidation, and motor activity confirmed in animal models. [14] Neuroprotective with potentials in senile dementia and Alzheimer's. [18][19][20][21]
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PAF Antagonism & Anti-Aggregant
Ginkgolides are selective antagonists of PAF (Platelet Activating Factor) — ginkgolide B was the first natural PAF inhibitor identified. PAF is a phospholipid mediator secreted by platelets, leukocytes, macrophages, and endothelial cells, involved in platelet aggregation, thrombus formation, inflammation, allergy, and asthma. Ginkgolide B inhibits platelet aggregation in a cAMP- and cGMP-dependent manner by activating MMP-9. [62][63]
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Vascular Protective & Vasodilatory
Relaxes vascular walls through inhibition of calcium channels, activation of NO release, and liberation of prostacyclin PGI₂ in endothelium and aortic vascular muscles (bilobalide and EGb 761). [27] Arteriolar vasodilator, venous vasoconstrictor through increased adrenergic tone; reinforces capillary resistance; protects mesenteric arterioles of aged rats via Akt/FoxO3a signalling. [17] Comprehensive vascular protection review confirms multiple mechanisms. [26]
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Antioxidant — Free Radical Scavenging
Flavonoids scavenge free radicals through multiple mechanisms — direct radical quenching and upregulation of glutathione transferase (ginkgolide A, bilobalide). Protects against lipid peroxidation and stabilises membranes against hypoxic degradation. Protects hippocampal cells against NO-induced toxicity via flavonoid constituents and protein kinase C pathway. [12] Comparative anticancer and antioxidant activities of EGb 761 fractions documented. [54]
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Anti-Inflammatory — PAF Pathway
Inhibits PAF-induced inflammatory reactions, basophil degranulation, and bronchoconstriction. Reduces inflammatory mediators SOD, MDA, TNF-α, NF-κBp65, and IL-6 in colitis models. Provides protective effect against prostacyclin PGI₂ degradation via NO. Anti-inflammatory activity operates through the unique PAF antagonism mechanism rather than COX inhibition — a distinct anti-inflammatory pathway from standard NSAIDs.
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Anti-Hypoxic & Metabolic Activator
Bilobalide increases glucose and oxygen uptake by cerebral cells, raises the hypoxia threshold, and activates cortical metabolism. Increases vigilance in elderly subjects. Increases brain serotonin (5-hydroxytryptamine) via synaptic mechanisms and inhibits accumulation of acylglycerols and free fatty acids in rat hippocampus — two metabolic effects relevant to age-related cognitive decline.
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Antiviral (Biflavonoids)
Certain biflavonoids — specifically ginkgetin (ginkgetol) — inhibit influenza sialidase, the enzyme responsible for viral release from host cells. [25] Biflavonoids documented as antiviral constituents independent of the terpene lactone fraction. This antiviral mechanism is distinct from the immunostimulant antiviral activity of echinacea and andrographis — ginkgo acts through direct viral enzyme inhibition.
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Serotonergic & Monoaminergic
Ginkgo increases synaptic serotonin (5-HT) levels and has documented monoaminergic effects including pharmacological and biochemical influences on learning, memory consolidation, and motor activity. [14] This serotonergic activity contributes to the antidepressant-adjacent and anti-stress properties documented in clinical use, and underpins the evidence for schizophrenia adjuvant treatment. [40]
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Anti-Vitiligo
Ginkgo biloba reduces depigmentation and improves repigmentation in vitiligo — confirmed in an open-label pilot clinical trial. [28] The mechanism involves antioxidant protection of melanocytes against oxidative damage and anti-inflammatory reduction of autoimmune melanocyte destruction. This is one of the few documented dermatological indications for an oral herbal extract.
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Antidiabetic & Metabolic
Improves glycated haemoglobin (HbA1c) and serum HDL cholesterol in metabolic syndrome. [46] EGb 761 as adjuvant to type 2 diabetes management with metformin: double-blind RCT shows safety and efficacy. [48] Potentiates statin effect in dyslipidaemia. [44] Preventive effect on diabetic nephropathy through suppression of tissue transglutaminase. [50]
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Anticancer Potential (Preliminary)
EGb 761 induces antioxidant response and modulates Golgi system in human cancer cell lines. [53] Comparative anticancer activity documented for different EGb 761 fractions. [54] A 2023 review catalogued ginkgo's potential as a source of biologically active anticancer compounds. [55] Evidence is preclinical — clinical translation not yet established.
Clinical Applications
Clinical Indications
Indications of the whole plant from the Wikiphyto source, organised by evidence strength.
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Cognitive & Neurodegenerative
Primary Indication · Multiple Systematic Reviews
- Alzheimer's disease & mixed dementia: EGb 761 comparable to cholinesterase inhibitors (donepezil, rivastigmine) — systematic review (Wettstein, 2000) [29]; non-cholinergic mechanisms offer a complementary rather than competitive treatment approach [33]
- Cognitive decline prevention: German cohort study — standardised ginkgo prescriptions associated with reduced dementia incidence in mild cognitive impairment [35]
- 240 mg/day EGb 761: systematic review (2016) confirms efficacy in Alzheimer's with no side effects at this dose [38]; stabilises or reduces decline after 22–26 weeks in 2,561 patients [39]
- Memory in healthy adults ≥60 years: double-blind RCT — neuropsychological improvements in cognitively intact older adults [51]
- Schizophrenia adjuvant: EGb 761 added to haloperidol improved positive symptoms in refractory schizophrenia [40]
- Parkinson's disease: systematic review of animal models suggests potential [52]
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Vascular & Circulatory
EMA-Supported Indications
- Peripheral arterial disease with intermittent claudication: arteriolar vasodilation and PAF antagonism reduce ischaemic pain with walking
- Raynaud's disease: vasodilatory and vascular protective properties clinically applicable to vasospastic disorders
- Tinnitus, vertigo, hearing loss of ischaemic origin: EMA-supported indications — vascular and neuroprotective mechanisms relevant to inner ear circulation
- Vitiligo: open-label pilot trial — reduces depigmentation and improves repigmentation [28]
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Metabolic & Endocrine
Clinical Evidence
- Metabolic syndrome: review confirms benefits on multiple cardiometabolic parameters [45]
- Type 2 diabetes adjuvant: double-blind RCT — EGb 761 adjuvant to metformin: safe and efficacious [48]; improves HbA1c and HDL [46]
- Dyslipidaemia: potentiates statin effects in a systematic review [44]
- Diabetic nephropathy prevention through tissue transglutaminase suppression [50]
⛰️
Altitude Sickness — Conflicting Evidence
Honest Evidence Presentation
- Positive result — Chilean Andes (3,696 m): 80 mg twice daily, started 24h before ascent, significantly reduced acute mountain sickness incidence vs placebo and acetazolamide via antioxidant and vasodilatory mechanisms [41]
- Negative result — Everest Base Camp (4,000+ m): RCT in 487 trekkers — ginkgo was NOT effective for acute mountain sickness prevention; acetazolamide 250 mg twice daily was effective [42]
- Meta-analysis: larger controlled trials required before definitive recommendations can be made [43]
Pharmacodynamics
Mode of Action
A synergy between ginkgolides, bilobalide, and flavonoids produces broader effects than any single fraction — confirmed by comparative neuroprotection studies. [56]
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PAF Antagonism — Ginkgolide B
Ginkgolide B was the first naturally occurring inhibitor of Platelet Activating Factor (PAF) ever identified — a landmark discovery in lipid pharmacology. PAF is a phospholipid mediator secreted by platelets, leukocytes, macrophages, and endothelial cells that drives platelet aggregation, thrombus formation, bronchoconstriction, and inflammatory cascades. Ginkgolide B selectively occupies PAF receptors, preventing PAF from activating its signalling cascade — inhibiting platelet aggregation in a cAMP/cGMP-dependent manner via MMP-9 activation. This mechanism explains ginkgo's anti-thrombotic, anti-inflammatory, anti-asthmatic, and vascular protective properties. [62]
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Cerebral Metabolism Activation — Bilobalide
Bilobalide increases glucose and oxygen uptake by cerebral cells, raises the ischaemia/hypoxia threshold, and activates cortical metabolic pathways. It also induces vascular relaxation through calcium channel inhibition, NO release activation, and prostacyclin PGI₂ liberation in aortic endothelium and vascular smooth muscle. [27] This metabolic activating effect is the mechanistic basis for ginkgo's utility in age-related cognitive decline, where reduced cerebral glucose utilisation is a key pathological feature.
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GABA-A Modulation — Interaction Caveat
Ginkgolides act as agonists at GABA-A receptors — the same receptor target as benzodiazepines and valerian's valerenic acid. This mechanism has a dual significance: it may contribute to ginkgo's anxiolytic and cognitive-stabilising properties, but it also creates a clinically important drug interaction. Ginkgo should not be combined with benzodiazepines because the additive GABA-A activity could unexpectedly potentiate sedation. This interaction is documented and listed in the Wikiphyto source as a contraindication.
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Flavonoid Antioxidant Synergy
Flavonoid glycosides scavenge reactive oxygen species including superoxide anion, hydroxyl radical, and peroxynitrite. This free radical scavenging protects hippocampal cells against NO-induced toxicity [12] and contributes to membrane stabilisation against hypoxic degradation. Comparative studies confirm that a combination of flavonoids, terpenoids, and their mixture from EGb 761 produces better neuroprotection in ischaemia-reperfusion than either fraction alone — confirming pharmacological synergy as the operating principle. [56]
Comparative Analysis
Ginkgo biloba vs Donepezil
The direct head-to-head comparison that patients, families, and clinicians actually search for — based on primary clinical trial data and systematic reviews.
Clinical Interpretation
Ginkgo biloba EGb 761 is the only phytomedicine to have been tested head-to-head against a prescription Alzheimer's drug in a randomised clinical trial — with comparable results. Its non-cholinergic mechanism means it does not duplicate donepezil's action and could be complementary rather than substitutive. Ginkgo's additional vascular protective properties may be particularly relevant in vascular and mixed dementias where cerebrovascular disease coexists. The decision between the two — or whether to combine them — should be made with a qualified clinician.
Emerging Evidence
Ginkgo & Post-COVID Cognitive Impairment
A 2024 published review specifically addresses EGb 761 as a candidate treatment for post-COVID syndrome — an emerging clinical application with strong mechanistic plausibility.
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The Post-COVID Mechanism Problem
Post-COVID syndrome (Long COVID) cognitive impairment — colloquially "brain fog" — involves three overlapping pathological mechanisms: neuroinflammation (microglial activation and cytokine-mediated neuronal injury), oxidative stress (mitochondrial dysfunction and reactive oxygen species accumulation), and mitochondrial dysfunction (impaired cellular energy metabolism). These are precisely the three mechanisms most directly targeted by EGb 761's documented pharmacological profile.
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2024 Review — Mueller & Müller
A review published in Journal of Neural Transmission (Mueller JK, Müller WE, 2024) [24] specifically addressed Ginkgo biloba and Rhodiola rosea as "multi-target drugs" for post-COVID cognitive impairment and fatigue. The review identified EGb 761's antioxidant, anti-inflammatory, and metabolic-activating properties as pharmacologically matched to the post-COVID pathophysiological triad. The authors noted that mitochondrial dysfunction — a core feature of Long COVID — is directly addressed by bilobalide's metabolic activation mechanisms.
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Ginkgo + Rhodiola Combination
A separate study (Al-Kuraishy, 2015) [23] demonstrated that the combination of Ginkgo biloba and Rhodiola rosea produced a more significant effect on psychomotor vigilance and short-term working memory accuracy than either plant used alone — suggesting additive or synergistic cognitive enhancement. This combination has been specifically proposed for post-COVID cognitive impairment given the complementary mechanisms of the two plants.
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Evidence Status & Caveats
As of 2025, no completed large-scale clinical trials have specifically recruited post-COVID patients to test EGb 761 efficacy. The 2024 review is mechanistic and observational — not a clinical trial. The existing evidence is a biologically plausible hypothesis supported by EGb 761's established mechanisms, not a proven clinical indication. Patients with post-COVID cognitive symptoms should consult a qualified physician before initiating ginkgo or any supplement regimen.
Legal & Regulatory Status
Regulation
French Pharmacopoeia — List A (Leaf)
The leaf of Ginkgo biloba L. is listed on the French Pharmacopoeia, List A — designating medicinal plants whose use in preparations intended for the public is reserved for pharmacy.
EMA / HMPC — European Union Herbal Monograph
The European Medicines Agency Committee on Herbal Medicinal Products (HMPC) has issued a formal EU herbal monograph on Ginkgo biloba L., folium (EMA/HMPC/321097/2012), covering standardised leaf extract for cognitive, vascular, and otological indications. This monograph covers both well-established use and traditional use categories. [58]
Germany — Prescription Status (Tanakan®)
In Germany, EGb 761 (marketed as Tanakan® and generics) is available as a prescription phytomedicine for cognitive insufficiency and peripheral arterial circulatory disorders. The German Commission E provided a positive monograph. A plain leaf extract not meeting EGb 761 specifications cannot claim equivalence with the prescription product.
Clinical Safety
Safety & Precautions
EGb 761 has a well-characterised safety profile at standard doses. The most critical safety issues are antiplatelet activity, CYP interactions, ginkgolic acid contamination in non-standardised products, and the absolute prohibition on using seeds or fruits.
Adverse Effects
- GI effects: abdominal pain, diarrhoea, and vertigo most frequently reported — documented in the GuidAge study (2-31-00240-011)
- Allergic reactions: rare — caused by ginkgolic acids; risk dramatically higher in non-standardised products exceeding 5 ppm ginkgolic acid [61]; up to 48,000 mcg/day possible in untested products vs 0.6 mcg recommended maximum
- Bleeding: antiplatelet effect via PAF antagonism (ginkgolide B) — risk increases when combined with anticoagulants or antiplatelets [62][63]
- Seeds and fruits: toxic — contain alkaloids; must never be consumed; only standardised leaf preparations are safe
Contraindications & Interactions
- Haemophilia — absolute contraindication: antiplatelet activity is clinically dangerous in haemophilia and other bleeding disorders
- Anticoagulants (warfarin): multiple documented pharmacodynamic interactions — do not combine without medical supervision [64][65][66]
- Aspirin and NSAIDs: increased bleeding time; avoid combination — PAF antagonism adds to antiplatelet effects [67]
- Benzodiazepines: ginkgolides are GABA-A agonists — avoid combination due to potential additive sedation
- CYP450: CYP3A4, 2C9, and 2C19 interactions documented [68]; may decrease hypoglycaemic action of tolbutamide via CYP2C9 [69]
- OATP transporters: apigenin, kaempferol, quercetin may interact with OATP2B1 and OATP1A2 organic anion transporters [70]
- Epilepsy — caution: avoid or use with caution in seizure disorders; case report of fatal seizures with herb-drug interaction [59][60]
- Pregnancy and lactation: avoid — insufficient data on foetal exposure and breast milk transfer [57][58]
- Surgery: stop treatment 3–4 days before any surgical procedure due to antiplatelet activity
Clinical Disclaimer: This monograph is for educational and professional reference only. It does not constitute medical advice, diagnosis, or treatment guidance. Ginkgo biloba EGb 761 has clinically significant drug interactions with anticoagulants, antiplatelets, and benzodiazepines. Always consult a qualified healthcare provider before initiating any phytotherapeutic regimen.
Common Questions
Frequently Asked Questions
What is EGb 761 and why does it matter?
EGb 761 is a precisely defined standardised dry extract of Ginkgo biloba leaves — not a brand name, but an extract specification. It must be concentrated at 35–67:1 from raw leaf and contain 22–27% flavonoid glycosides, 5–7% terpene lactones (ginkgolides + bilobalide), and — critically — less than 5 ppm ginkgolic acid. Every clinical trial demonstrating ginkgo's efficacy for cognitive and vascular indications used EGb 761 or a comparable standardised extract. Plain ginkgo leaf tea is ineffective because ginkgolides are not water-soluble. Non-standardised capsules without ginkgolic acid control may be unsafe. When choosing a ginkgo supplement, verify the standardisation parameters match EGb 761 specifications.
Is ginkgo biloba as effective as donepezil for Alzheimer's disease?
A randomised double-blind placebo-controlled trial (Mazza et al., Eur J Neurol, 2006) directly compared EGb 761 with donepezil in Alzheimer's dementia and found comparable efficacy on cognitive outcomes. A systematic review (Wettstein, 2000) concluded ginkgo extracts are comparable to second-generation cholinesterase inhibitors including donepezil, rivastigmine, and metrifonate. The key distinction: ginkgo acts through non-cholinergic mechanisms (PAF antagonism, antioxidant, vascular), while donepezil inhibits acetylcholinesterase. This means they are potentially complementary rather than equivalent alternatives. Donepezil is FDA-approved and first-line; ginkgo is EMA-registered and supported by systematic reviews. Clinical decisions should involve a neurologist or geriatrician.
Can ginkgo biloba help with post-COVID brain fog?
Mechanistically plausible — but not clinically proven. Post-COVID cognitive impairment involves neuroinflammation, oxidative stress, and mitochondrial dysfunction — three pathological targets directly addressed by EGb 761's documented mechanisms. A 2024 review in Journal of Neural Transmission (Mueller & Müller) specifically proposed Ginkgo biloba and Rhodiola rosea as multi-target treatments for post-COVID cognitive impairment and fatigue. However, as of 2025, no completed large-scale clinical trial has specifically tested EGb 761 in post-COVID patients. The evidence is mechanistic and preliminary. Consult a physician before using ginkgo for post-COVID symptoms.
What is the ginkgolic acid contamination problem?
Ginkgolic acids are allergenic and potentially genotoxic compounds in ginkgo leaves. The recommended maximum daily intake in Germany is 0.6 micrograms. Testing of 20 commercial ginkgo products found that some could deliver up to 48,000 micrograms per day — 80,000 times the recommended limit. EGb 761 specification requires below 5 ppm ginkgolic acid. Many generic "ginkgo extract" products do not specify or control ginkgolic acid content, creating a genuine safety risk. Always choose products standardised to below 5 ppm ginkgolic acid, with third-party verification available via certificate of analysis.
Does ginkgo biloba interact with warfarin or blood thinners?
Yes — this is a clinically documented and significant interaction. Ginkgolide B inhibits PAF (Platelet Activating Factor), producing antiplatelet activity that adds to the effect of anticoagulants. Multiple pharmacological studies confirm ginkgo inhibits platelet aggregation. Ginkgo should not be combined with warfarin, aspirin, NSAIDs, or other antiplatelet/anticoagulant drugs without medical supervision. Ginkgo is absolutely contraindicated in haemophilia. Treatment must be stopped 3–4 days before any surgical procedure. This interaction is one of the most well-documented herb-drug interactions and should be taken seriously.
Does ginkgo biloba prevent dementia?
There is supportive but not conclusive evidence. A German retrospective cohort study (Bohlken et al., J Alzheimers Dis, 2022) found that patients with mild cognitive impairment who were prescribed standardised ginkgo extract had significantly lower dementia incidence than matched controls. A 2024 systematic review of clinical trials in Antioxidants (Pagotto et al.) concluded that evidence is promising but further large-scale controlled trials are required. The existing data most consistently supports a potential protective effect in people who already show mild cognitive impairment — not in cognitively healthy younger individuals. Ginkgo is not a proven dementia prevention strategy but has enough evidence to warrant continued clinical investigation.
Why doesn't ginkgo tea work?
Ginkgolides — the terpene lactones responsible for PAF antagonism, anti-ischaemic activity, and a large part of the neuroprotective effect — are not water-soluble. They do not dissolve in hot water and are therefore absent from any aqueous preparation including teas, infusions, and water-based extracts. A ginkgo tea delivers only the flavonoid fraction, which provides antioxidant benefit but misses the full pharmacological profile. Only hydroalcoholic standardised extracts (EGb 761 or equivalent) contain both the flavonoid glycoside fraction and the terpene lactone fraction — and are the only forms with clinical trial evidence.
Primary Literature
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