herb · for poor memory
Ginkgo
Meant to improve blood flow in the brain and support the messenger memory uses.
Say that in clinical terms
Promotes hippocampal neuroplasticity and modulates acetylcholine neurotransmission, improving memory consolidation.
How strong is the research?
A 5-year trial in 2,854 older adults with memory complaints found no reduction in dementia risk.
1 paper read, 1 against.
Who was studied: French adults over 70 who had raised memory complaints with their doctor, followed for five years.
How much to take
daily
120–240 mg
Effects may take 4-6 weeks. Best results with standardized extracts.
Before you take it
- Increases bleeding risk when combined with warfarin; pharmacovigilance data show HR 1.38 (95% CI 1.20–1.58) vs. warfarin alone. Additive risk with antiplatelet agents (aspirin, clopidogrel) and NSAIDs.
- Discontinue at least 2 weeks before any surgical or invasive procedure due to anticoagulant and antiplatelet properties.
- Contraindicated in pregnancy: possible uterotonic effects and increased peripartum bleeding risk documented.
- In vitro CYP2C9 and CYP3A4 inhibition by biflavonoid components is confirmed; clinical pharmacokinetic studies at recommended doses (120–240 mg/day EGb761) show no significant in vivo CYP interactions. Minor effects appear only at supra-therapeutic doses (≥360 mg/day). Pharmacokinetic caution is appropriate for narrow-therapeutic-index co-medications.
- No Tolerable Upper Intake Level (UL) established by NIH ODS or IOM for Ginkgo biloba. Standardized extract (EGb761) has been used safely in trials up to 6 years at standard doses; raw ginkgo seeds and crude plant material contain ginkgotoxin (4'-O-methylpyridoxine) and carry seizure risk — standardized extract removes this compound.
- Breastfeeding safety is unknown; use during lactation is not recommended.
What we make of it
The two largest independent trials both found nothing.
The detail
One five-year trial found no effect, and a separate government-funded trial of 3,069 people found none either. Those are the two biggest independent tests of ginkgo for memory and both failed. The acetylcholine mechanism we describe is not an established route for ginkgo anyway.