Ginkgo

Metadata

Approved Indications

Commission E (Germany)

• Approved: Symptomatic treatment of disturbed performance in organic brain syndrome within the framework of an overall therapeutic concept in cases of dementing syndromes with the following principal symptoms: memory deficits, disturbances in concentration, depressive emotional condition, dizziness, tinnitus, and headache
• Approved: Improvement of pain-free walking distance in peripheral arterial occlusive disease (Fontaine stage II)
• Approved: Vertigo and tinnitus of vascular and involutional origin

ESCOP

• Approved: Cognitive impairment including dementia syndromes
• Approved: Peripheral arterial occlusive disease (intermittent claudication)
• Approved: Vertigo and tinnitus of vascular origin

EMA/HMPC (2015)

• Well-established use: Improvement of (age-associated) cognitive impairment and of quality of life in mild dementia
• Traditional use: Relief of heaviness of legs and sensation of cold in hands and feet associated with minor circulatory disturbances

Agreement/Disagreement

All three European bodies agree on the core cognitive/dementia indication. The tinnitus and peripheral vascular indications are recognized by Commission E and ESCOP but the EMA’s 2015 monograph focuses on cognitive impairment/dementia. There is growing consensus that tinnitus benefits are secondary to cognitive improvement rather than a standalone indication.

Conditions Treated

Primary (Strong Evidence)

• Mild-to-moderate dementia — Both Alzheimer’s type and vascular dementia. Symptomatic treatment: cognition, neuropsychiatric symptoms, activities of daily living, global clinical impression.
• Mild cognitive impairment (MCI) — Symptomatic improvement demonstrated

Primary (Strong Negative Evidence)

• Dementia prevention — Two mega-trials (GEM and GuidAge) conclusively showed NO preventive effect. This is a robustly negative finding.

Secondary (Mixed Evidence)

• Tinnitus as concomitant symptom of dementia — Meta-analysis shows benefit when tinnitus accompanies dementia
• Tinnitus as primary complaint — Cochrane review (2013) found NO evidence of efficacy. Four trials, n=1,543: ginkgo was not effective for standalone tinnitus.
• Peripheral arterial occlusive disease — Some evidence for improved walking distance; less studied in recent years

Traditional Use

• Heavy legs, cold hands/feet associated with minor circulatory disturbances

Mechanism of Action

EGb 761 has a multi-target pharmacological profile:

1. Antioxidant and Free Radical Scavenging

• Flavone glycosides are potent antioxidants
• Protects neurons from oxidative stress
• Improves mitochondrial function

2. Neuroprotection

• Bilobalide protects against glutamate-induced excitotoxicity
• Anti-apoptotic properties
• Protection of neuronal membrane integrity

3. Vascular Effects

• Promotes vasodilation and improves blood flow through arteries, veins, and capillaries
• Improves microcirculation
• Ginkgolides (especially ginkgolide B) are potent antagonists of platelet-activating factor (PAF) — This is the basis for the historical bleeding concern

4. Neurotransmitter Modulation

• Modulates cholinergic neurotransmission (enhances acetylcholine release)
• Affects serotonergic and dopaminergic systems
• Improves neuronal plasticity

5. Anti-inflammatory

• PAF antagonism contributes to anti-inflammatory effects
• Modulation of inflammatory cytokines

6. Amyloid and Tau Effects

• In vitro evidence for inhibition of amyloid-beta aggregation
• Some evidence for reduction of tau hyperphosphorylation [NEEDS-RESEARCH for clinical relevance]

Clinical Evidence Summary

Symptomatic Treatment of Dementia (Positive)

Systematic Review and Meta-Analysis (Gauthier & Schlaefke, 2014)

• Randomized placebo-controlled trials of EGb 761 in dementia
• EGb 761 at 240 mg/day for 22-26 weeks showed statistically significant improvements vs. placebo in:
  • Cognition (SKT, ADAS-Cog)
  • Activities of daily living (ADL scales)
  • Neuropsychiatric symptoms (NPI)
  • Global clinical impression (CGIC)
• Standardized mean differences significantly favored EGb 761
• [Source: PMC4259871]

Ihl et al. (2011) — Confirmatory Trial

• Design: Randomized, double-blind, placebo-controlled
• n = 404 outpatients with probable Alzheimer’s disease or vascular dementia with neuropsychiatric features (NPI >= 6)
• EGb 761 240 mg/day vs. placebo, 24 weeks
• Result: Significant improvement in cognition, neuropsychiatric symptoms, daily living activities, and global impression
• [Source: PubMed 22459264]

Expert Consensus (2019)

• International expert consensus recommends EGb 761 for treatment of dementia and MCI
• Recommended dose: 240 mg/day
• Noted as particularly appropriate when first-line antidementia drugs are not tolerated or contraindicated
• [Source: PMC6488894]

2024 Meta-Analysis of Patient Subgroups

• Confirmed EGb 761 is safe and effective in the treatment of mild dementia
• Consistent effects across patient subgroups
• [Source: Taylor & Francis, 2024]

Dementia Prevention (Negative)

GEM Trial (Ginkgo Evaluation of Memory Study)

• Design: Randomized, double-blind, placebo-controlled, multicenter (5 US academic centers)
• n = 3,069 community volunteers aged 75+ (2,587 with normal cognition, 482 with MCI)
• EGb 761 120 mg twice daily (240 mg/day) vs. placebo
• Follow-up: Median 6.1 years
• Primary outcome: Incidence of all-cause dementia
• Result: NEGATIVE. Rate of total dementia did not differ: 3.3/100 person-years (ginkgo) vs. 2.9/100 person-years (placebo); HR 1.12 (95% CI 0.94-1.33, p=0.21). Alzheimer’s dementia rate also did not differ: HR 1.16 (95% CI 0.97-1.39, p=0.11).
• Publication: DeKosky et al. JAMA. 2008;300(19):2253-2262
• [Source: PMC2823569]

GuidAge Trial

• Design: Randomized, double-blind, placebo-controlled, multicenter (France, primary care)
• n = 2,854 participants aged 70+ with spontaneous memory complaints
• EGb 761 120 mg twice daily (240 mg/day) vs. placebo
• Follow-up: 5 years
• Primary outcome: Conversion to Alzheimer’s disease
• Result: NEGATIVE. Long-term use of EGb 761 did not reduce the risk of progression to Alzheimer’s disease compared with placebo.
• Post hoc analysis: A potential late effect of EGb 761 was observed when a more appropriate statistical test was applied, but this was exploratory and not the pre-specified primary analysis.
• Publication: Vellas et al. Lancet Neurology. 2012;11(10):851-859

Significance of the Prevention Trials

These two mega-trials (combined n = 5,923) represent some of the largest herbal medicine trials ever conducted. Their negative results for prevention are robust and have significantly shifted the narrative around ginkgo from “prevents dementia” to “treats but does not prevent dementia.” This distinction is clinically important and frequently misunderstood.

Tinnitus

Cochrane Review (Hilton et al., 2013)

• 4 trials, n = 1,543 participants with primary complaint of tinnitus
• Conclusion: NO evidence that Ginkgo biloba is effective for tinnitus as a primary condition
• Individual trials also failed to show benefit

Tinnitus as Concomitant Symptom of Dementia

• Meta-analysis by Spiegel et al. (2018): EGb 761 alleviates concomitant tinnitus and dizziness in patients with dementia
• Interpretation: The tinnitus improvement is likely secondary to overall cognitive/neurological improvement in dementia patients, not a direct anti-tinnitus effect

European vs. US/Anglophone Consensus

The Two-Narrative Problem

Ginkgo suffers from a narrative confusion: the strong positive evidence for symptomatic treatment of existing dementia is often eclipsed by the equally strong negative evidence for prevention. In the US especially, the GEM trial’s negative prevention result is often misinterpreted as meaning “ginkgo doesn’t work for anything cognitive,” when the actual conclusion should be “ginkgo treats but does not prevent.”

Safety Profile

Contraindications

• Known hypersensitivity to Ginkgo biloba preparations
• Historically: Concurrent use with anticoagulants was listed as a contraindication, but more recent evidence has challenged this (see Drug Interactions below)

Drug Interactions

The Bleeding Risk Question

• Historical concern: Ginkgolides are PAF antagonists, leading to theoretical bleeding risk. Multiple case reports of spontaneous bleeding events in ginkgo users.
• Controlled trial evidence: A dedicated 2021 study found that EGb 761 does NOT affect blood coagulation and bleeding time in patients with probable Alzheimer’s dementia. [Source: PMC8701823]
• Interaction with warfarin: A formal interaction study did not find clinically relevant drug-drug interactions between EGb 761 and warfarin.
• Interaction with aspirin: Well-controlled trials found no relevant interactions between EGb 761 and the platelet anti-aggregatory effects of acetylsalicylic acid.
• Current assessment: The bleeding risk of standardized EGb 761 appears to be overstated based on case reports that may have had confounding factors. However, prudent clinical practice still advises caution with concurrent high-risk anticoagulation.

Other Drug Interactions

• CYP450: For EGb 761 specifically, the potential for clinically relevant drug-drug interactions is reported to be negligible
• Anticonvulsants: Theoretical concern for reduced seizure threshold, based on case reports [UNCERTAIN]
• Overall: EGb 761 has a considerably more favorable drug interaction profile than often assumed

Side Effects

• Common: Headache, GI complaints (nausea, diarrhea), dizziness
• Uncommon: Allergic skin reactions
• Rare: Stevens-Johnson syndrome (extremely rare case reports with non-standardized products)
• Ginkgolic acids: These are toxic alkylphenols that MUST be controlled to <5 ppm in EGb 761. Non-standardized products may contain higher levels and carry additional allergenic and mutagenic risks.

Pregnancy and Lactation

• Pregnancy: Not recommended. PAF antagonism could theoretically affect implantation and placental function. No adequate human studies.
• Lactation: Not recommended. Insufficient data.

Product Quality Is Critical

The safety and efficacy of ginkgo depend heavily on using a properly standardized extract:

• EGb 761: 24% flavone glycosides, 6% terpene lactones, <5 ppm ginkgolic acids
• Non-standardized products may have insufficient active constituents AND excessive toxic compounds (ginkgolic acids)
• The difference between EGb 761 and a random “ginkgo supplement” is clinically significant

Clinical Dosage

For Dementia/Cognitive Impairment

• EGb 761: 240 mg once daily (current standard; replaces older 120 mg BID regimen)
• OR: 120 mg twice daily (older dosing schedule still used in some protocols)
• Both regimens deliver 240 mg/day total
• The once-daily 240 mg regimen was validated in the 2011 Ihl trial

Commission E / ESCOP

• 120-240 mg dry extract in 2-3 divided doses daily
• Standardized to 22-27% flavone glycosides and 5-7% terpene lactones

Duration

• Minimum 8 weeks for initial assessment (12 weeks preferable)
• Continuation therapy: 6-12 months; reassess regularly
• Long-term use appears safe (GEM and GuidAge trials used 5-6 years of treatment without safety signals)

Onset

• Clinical effects may begin within 4-8 weeks
• Full therapeutic benefit typically at 12-24 weeks

Sources

• EMA/HMPC: Well-established use monograph on Ginkgo biloba (2015)
• Commission E Monograph: Ginkgo biloba leaf
• ESCOP Monograph: Ginkgo biloba leaf
• DeKosky ST et al. Ginkgo biloba for prevention of dementia: a randomized controlled trial (GEM). JAMA. 2008;300(19):2253-2262. PMC2823569
• Vellas B et al. Long-term use of standardised ginkgo biloba extract for the prevention of Alzheimer’s disease (GuidAge). Lancet Neurol. 2012;11(10):851-859
• Gauthier S, Schlaefke S. Efficacy and tolerability of Ginkgo biloba extract EGb 761 in dementia: a systematic review and meta-analysis. J Psychiatr Res. 2014. PMC4259871
• Ihl R et al. Ginkgo biloba extract EGb 761 in dementia with neuropsychiatric features: a randomised, placebo-controlled trial. Int J Geriatr Psychiatry. 2011;26(11):1186-1194. PubMed 22459264
• Hilton MP et al. Ginkgo biloba for tinnitus. Cochrane Database Syst Rev. 2013
• Spiegel R et al. EGb 761 alleviates neurosensory symptoms in patients with dementia: a meta-analysis. PubMed 29942120
• EGb 761 and blood coagulation: PMC8701823
• Expert consensus on EGb 761: PMC6488894
• EGb 761 in mild dementia (2024 meta-analysis): Taylor & Francis
• StatPearls: Ginkgo Biloba (NCBI NBK541024)
• Ginkgo biloba leaf extract EGb 761 overview of systematic reviews (2025): ScienceDirect

Connections

• AChE-related mechanism connects to lemon balm’s cholinergic activity: see Lemon Balm
• Bleeding risk discussion provides contrast with St. John’s Wort’s drug interaction profile: see St Johns Wort
• The importance of standardized extracts (EGb 761 vs. generic ginkgo) mirrors the Silexan story: see Lavender