Ginkgo
Dementia reviews disagree. Three meta-analyses report small to modest cognition gains, at low certainty in a 2026 Cochrane review, while a 2009 Cochrane review found inconsistent results. A 3,069-person trial found no drop in new dementia. Mild cognitive impairment, healthy memory, tinnitus and walking distance did not change. Fifteen case reports describe bleeding, and pooled trials show no clotting changes.
Add to Bio HackChecked 2026-11-09
- Status
- Dietary supplement in the US. Not approved by the FDA as a drug for any use.
- Also called
- Ginkgo biloba, maidenhair tree, ginkgo leaf extract, EGb 761, Tebonin, Tanakan, ginkgolides
- Taken for
- memory, focus, brain health, dementia, Alzheimer's, tinnitus, circulation, leg pain when walking
Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on
Shown to help0
No benefit shown in research yet.
Reported risks1
What people take it for, and what was found
Mixed results1
Symptoms of dementia
Mixed results: some reviews found small cognition gains in dementia, mostly with one branded extract, while others found inconsistent or no benefit.
The numbers and sources
- Effect
- A Cochrane review of 36 trials found inconsistent results for cognition, daily living, mood and carer burden. Of the 4 most recent trials, 3 found no difference from placebo and 1 found very large effects. In 925 Alzheimer's patients from 9 trials there was no consistent benefit [1]. A meta-analysis of 9 EGb 761 trials (2,372 patients) found cognition favored ginkgo (SMD -0.58, 95% CI -1.14 to -0.01) and daily living did not differ significantly (SMD -0.32, 95% CI -0.66 to 0.03) [2]. A 2014 meta-analysis of 9 trials (2,561 patients, 22 to 26 weeks) reported cognition (WMD -2.86) and daily living (SMD -0.36) favored EGb 761, mainly at 240 mg a day [3]. A 2026 Cochrane review of 13 placebo-controlled dementia trials (3,288 participants) found cognition at 6 months may be better on ginkgo (MD -1.86 on the Syndrom-Kurztest, 95% CI -3.48 to -0.24, 9 studies, 2,801 participants) and daily living slightly better (MD -0.19, 95% CI -0.35 to -0.03, 8 studies), both at low certainty [4].
- Population
- People with Alzheimer's, vascular or mixed dementia, or cognitive impairment [1][2][3][4].
- Sources
- [1], [2], [3], [4]
- Caveats
- The reviews disagree. Heterogeneity was high [2], with I² of 91% to 96% for cognition and daily living in [4]. Only 4 of 82 studies in [4] were at low risk of bias in all domains. The Cochrane authors note many early trials were small, used unsatisfactory methods, and publication bias cannot be excluded [1]. Most trials tested one branded extract, EGb 761 [1][2][3].
Not shown to help5
Preventing dementia
One trial found 120 mg twice a day did not lower dementia or Alzheimer's incidence over 6 years in adults aged 75 or older.
The numbers and sources
- Effect
- In 3,069 adults aged 75 or older followed a median 6.1 years, 120 mg twice a day did not lower dementia incidence (HR 1.12, 95% CI 0.94 to 1.33) or Alzheimer's incidence (HR 1.16, 95% CI 0.97 to 1.39). Dementia rates were 3.3 per 100 person-years on ginkgo and 2.9 on placebo. Progression from mild cognitive impairment did not change (HR 1.13) [5].
- Population
- 2,587 adults with normal cognition and 482 with mild cognitive impairment [5].
- Sources
- [5]
- Caveats
- One trial, funded by the NIH [5].
- Why limited
- This rests on one trial, of 3,069 people. Strength counts independent studies that agree, so one trial is limited at any size.
Mild cognitive impairment
Not shown to change cognition, daily living or global status at 6 months in adults with mild cognitive impairment.
The numbers and sources
- Effect
- In a 2026 Cochrane review, 12 placebo-controlled trials (1,913 participants) tested ginkgo in mild cognitive impairment. At 6 months, ginkgo probably had little to no effect on global clinical status (MD -0.03, 95% CI -0.06 to 0.01, 3 studies, 631 participants), cognition (ADAS-cog MD -0.07, 95% CI -0.67 to 0.51, 2 studies, 508 participants) or daily living (1 study, 350 participants), at moderate certainty [4].
- Population
- Adults with mild cognitive impairment [4].
- Sources
- [4]
- Caveats
- Each pooled outcome draws on 1 to 3 of the 12 trials [4].
Memory and attention in healthy people
Not shown to improve memory, attention or executive function in healthy people.
The numbers and sources
- Effect
- Across RCTs in healthy people, effect sizes were near zero for memory (d -0.04, 95% CI -0.17 to 0.07, 13 trials, 1,132 participants), executive function (d -0.05) and attention (d -0.08). Results did not vary with age, trial length, dose or sample size [6].
- Population
- Healthy individuals [6].
- Sources
- [6]
- Caveats
- Effect sizes were derived from the trials that reported usable data [6].
Tinnitus
Not shown to change tinnitus severity, loudness or quality of life in adults with tinnitus, at very low certainty.
The numbers and sources
- Effect
- A Cochrane review of 12 studies (1,915 participants) found ginkgo may have little to no effect on tinnitus severity at 3 to 6 months (MD -1.35 on a 0 to 100 scale, 95% CI -8.26 to 5.55, 2 studies, 85 participants, very low certainty). Loudness and quality of life also showed little to no difference [7].
- Population
- Adults with subjective tinnitus [7].
- Sources
- [7]
- Caveats
- Risk of bias was high or unclear, and limited pooling was possible [7].
Walking distance with leg artery disease
Not shown to give a clinically meaningful gain in pain-free walking distance in people with intermittent claudication.
The numbers and sources
- Effect
- In 11 placebo-controlled trials (477 participants), pain-free walking distance rose by an effect size of 3.57 kcal (95% CI -0.10 to 7.23), about 64.5 meters on a flat treadmill at 3.2 km/h. Publication bias was likely to have inflated this [8].
- Population
- People with intermittent claudication [8].
- Sources
- [8]
- Caveats
- The review authors found no evidence of a clinically significant benefit [8].
Doses studied
The dementia prevention trial gave 120 mg twice a day [5]. Pooled dementia benefits were mainly at 240 mg a day of EGb 761 [3]. Hemostasis trials grouped doses at 240 mg a day or more as high dose [9].
Risks
Reported risks1
Bleeding case reports
Case reports: 15 bleeds linked in time to ginkgo, including 8 in the brain. Most people had other bleeding risk factors.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- A systematic review found 15 published case reports of bleeding temporally linked to ginkgo, including 8 intracranial bleeds. In 13, other bleeding risk factors were present. Six clearly reported that bleeding did not recur after ginkgo was stopped. Bleeding times, measured in 3 reports, were elevated on ginkgo [10].
- Population
- 15 case reports [10].
- Sources
- [10]
- Caveats
- The authors judged the evidence to suggest a possible causal association [10]. Case reports cannot give a rate.
Checked, no increase found3
Clotting and bleeding in controlled trials
Clotting tests did not change across 18 trials of standardized extract, and bleeding may be about as common as on placebo in tinnitus trials.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- In 18 RCTs (1,985 adults), standardized extract did not change ADP-induced platelet aggregation, fibrinogen, aPTT or prothrombin time. aPTT fell by 0.47 seconds at 240 mg a day or more, which the authors judged not clinically relevant [9]. In 4 tinnitus trials (1,154 participants), bleeding or seizures may not differ from placebo, at low certainty [7].
- Population
- Patients with dementia, artery disease or diabetes, and healthy volunteers [9]. Tinnitus trial participants [7].
- Sources
- [9], [7]
- Caveats
- Lab markers of clotting are not bleeding events. Trials were not sized to detect rare bleeds.
Warfarin
One small study found ginkgo did not change INR or warfarin clearance in healthy men given one warfarin dose.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- In 12 healthy men, 7 days of ginkgo did not change INR, platelet aggregation or warfarin clearance (INR AUC ratio 0.93, 90% CI 0.81 to 1.05) [11].
- Population
- 12 healthy men given one 25 mg warfarin dose [11].
- Sources
- [11]
- Caveats
- A single warfarin dose in healthy volunteers, not patients on long-term therapy.
Adverse events in trials
Adverse events were about as common as on placebo in dementia, mild cognitive impairment and prevention trials.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- The proportion with adverse events did not differ from placebo across dementia trials [1]. Dropouts and side effects did not differ in 9 EGb 761 trials [2]. Adverse effect profiles were similar over 6 years in the prevention trial [5]. In the 2026 Cochrane review, adverse events up to 12 months were probably similar in dementia (RR 0.95, 95% CI 0.90 to 1.00, 9 studies, 2,746 participants), and serious adverse events did not differ in mild cognitive impairment (RR 0.95, 95% CI 0.82 to 1.09, high certainty). In people with subjective cognitive complaints, one 3-month study found adverse events may be more common on ginkgo [4].
- Population
- Dementia, mild cognitive impairment and prevention trial participants [1][2][5][4].
- Sources
- [1], [2], [5], [4]
- Caveats
- Pooled trial data cannot rule out rare events such as those in the case reports [10]. The subjective cognitive complaints finding rests on one study [4].
Claims tested and not found
- That ginkgo prevents dementia. In 3,069 older adults over a median 6.1 years, dementia incidence did not differ from placebo [5].
- That ginkgo improves mild cognitive impairment. In 12 trials, global status, cognition and daily living at 6 months probably did not differ from placebo, at moderate certainty [4].
- That ginkgo sharpens memory in healthy people. Pooled effects on memory, executive function and attention were close to zero [6].
- That ginkgo relieves tinnitus. A Cochrane review found little to no effect on severity, at very low certainty [7].
- That ginkgo improves walking distance with leg artery disease. The gain of about 64.5 meters was not significant and likely inflated by publication bias [8].
Sources
- Birks J, Grimley Evans J. Ginkgo biloba for cognitive impairment and dementia. Cochrane Database of Systematic Reviews. 2009. https://doi.org/10.1002/14651858.CD003120.pub3
- Weinmann S, Roll S, Schwarzbach C, et al. Effects of Ginkgo biloba in dementia: systematic review and meta-analysis. BMC Geriatrics. 2010. https://doi.org/10.1186/1471-2318-10-14
- Tan MS, Yu JT, Tan CC, et al. Efficacy and Adverse Effects of Ginkgo Biloba for Cognitive Impairment and Dementia: A Systematic Review and Meta-Analysis. Journal of Alzheimer's Disease. 2014. https://doi.org/10.3233/JAD-140837
- Wieland LS, Ludeman E, Chi Y, et al. Ginkgo biloba for cognitive impairment and dementia. Cochrane Database of Systematic Reviews. 2026. https://doi.org/10.1002/14651858.CD013661.pub2
- DeKosky ST, Williamson JD, Fitzpatrick AL, et al. Ginkgo biloba for Prevention of Dementia: A Randomized Controlled Trial. JAMA. 2008. https://doi.org/10.1001/jama.2008.683
- Laws KR, Sweetnam H, Kondel TK. Is Ginkgo biloba a cognitive enhancer in healthy individuals? A meta-analysis. Human Psychopharmacology: Clinical and Experimental. 2012. https://doi.org/10.1002/hup.2259
- Sereda M, Xia J, Scutt P, et al. Ginkgo biloba for tinnitus. Cochrane Database of Systematic Reviews. 2022. https://doi.org/10.1002/14651858.CD013514.pub2
- Nicolaï SP, Kruidenier LM, Bendermacher BL, et al. Ginkgo biloba for intermittent claudication. Cochrane Database of Systematic Reviews. 2013. https://doi.org/10.1002/14651858.CD006888.pub3
- Kellermann AJ, Kloft C. Is There a Risk of Bleeding Associated with Standardized Ginkgo biloba Extract Therapy? A Systematic Review and Meta-analysis. Pharmacotherapy. 2011. https://doi.org/10.1592/phco.31.5.490
- Bent S, Goldberg H, Padula A, et al. Spontaneous bleeding associated with Ginkgo biloba: a case report and systematic review of the literature. Journal of General Internal Medicine. 2005. https://doi.org/10.1007/s11606-005-0114-4
- Jiang X, Williams KM, Liauw WS, et al. Effect of ginkgo and ginger on the pharmacokinetics and pharmacodynamics of warfarin in healthy subjects. British Journal of Clinical Pharmacology. 2005. https://doi.org/10.1111/j.1365-2125.2005.02322.x