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Ginkgo biloba and executive function: grade N

No benefit shown evidence. Direction: No effect.

N No benefit shown

Educational guidance, not medical advice

Why this grade

Rubric condition met: Adequate human RCTs found no meaningful effect: meta-analysis of 7 RCTs (534 participants) in healthy individuals, null; GEM executive-function domain null

The 2012 meta-analysis found an executive-function effect size of d = -0.05 (non-significant) across 7 RCTs. Planning and mental flexibility did not change after a single dose or after 6 weeks in a trial in students, and a 12-week trial found no effect on any measure in young adults. In older adults, the GEM trial's executive-function domain did not differ from placebo over a median 6.1 years.

How we grade evidence

Studies this grade rests on

EffectMixedNo effectSize shows participants (n)200520102015Meta-analysisRCTControlled trialSnitz 2009, 2009: RCT, n = 3,069, result not recordedLaws 2012, 2012: meta-analysis, n = 1,132, result not recordedBurns 2006, 2006: controlled trial, n = 197, result not recordedElsabagh 2005, 2005: RCT, n = 92, result not recorded
each study this grade rests on, by publication year and design. Solid: effect versus the comparator; half-filled: mixed; hollow: no effect; dashed: result not recorded yet. Larger marks had more participants.
Show the numbers
StudyYearDesignParticipantsResult
Elsabagh 20052005RCT92result not recorded
Burns 20062006controlled trial197result not recorded
Snitz 20092009RCT3069result not recorded
Laws 20122012meta-analysis1132result not recorded

Ginkgo biloba for preventing cognitive decline in older adults: a randomized trial.

Snitz BE, O'Meara ES, Carlson MC. Ginkgo biloba for preventing cognitive decline in older adults: a randomized trial JAMA, 2009. PMID 20040554

Result not recorded
Design
Randomized, double-blind, placebo-controlled trial (GEM study), median follow-up 6.1 years
Sample
n = 3,069
Population
Community-dwelling adults aged 72-96 with normal cognition or mild cognitive impairment
Funding
NIA and NCCIH (NIH) grants (PubMed grant list)

Differential cognitive effects of Ginkgo biloba after acute and chronic treatment in healthy young volunteers.

Elsabagh S, Hartley DE, Ali O. Differential cognitive effects of Ginkgo biloba after acute and chronic treatment in healthy young volunteers Psychopharmacology (Berl), 2005. PMID 15739076

Result not recorded
Design
Two placebo-controlled double-blind randomized experiments (single dose; 6 weeks)
Sample
n = 92
Population
Healthy university students
Funding
Dunhill Medical Trust (publisher full text, acknowledgements, read 2026-11-11)

Ginkgo biloba: no robust effect on cognitive abilities or mood in healthy young or older adults.

Burns NR, Bryan J, Nettelbeck T. Ginkgo biloba: no robust effect on cognitive abilities or mood in healthy young or older adults Hum Psychopharmacol, 2006. PMID 16329161

Result not recorded
Design
12-week double-blind, placebo-controlled trial
Sample
n = 197
Population
Healthy older adults (55-79) and young adults (18-43)
Funding
not stated (PubMed and Crossref records)

Is Ginkgo biloba a cognitive enhancer in healthy individuals? A meta-analysis.

Laws KR, Sweetnam H, Kondel TK. Is Ginkgo biloba a cognitive enhancer in healthy individuals? A meta-analysis Hum Psychopharmacol, 2012. PMID 23001963

Result not recorded
Design
Meta-analysis of randomized controlled trials (memory k=13, executive function k=7, attention k=8)
Sample
n = 1,132
Population
Healthy individuals
Funding
not stated (PubMed and Crossref records)

Search and history

Search (): ginkgo[ti] AND (memory[tiab] OR cognitive[tiab] OR attention[tiab]) AND healthy[tiab] AND randomized controlled trial[pt] AND humans[mh]

  • Graded N (proposed): Proposed in the monograph draft
  • N to N (approved): Editor sign-off November 13, 2026: grade matches the editor-approved final page