Phosphatidylserine
A membrane phospholipid with decent aging-memory data — much of it from a bovine-derived form nobody sells anymore.
100 mg three times daily (300 mg/day) in the memory trials
C Mixed or limited evidenceNootropics
Nootropics
Ginkgo Biloba
Also known as: ginkgo, maidenhair tree, EGb 761
The best-selling brain herb in history — and the one whose biggest, best trials came back empty.
Grade DPreliminary or weak evidence
Studied dose120-240 mg/day of EGb 761 standardized extract
TimingWith meals, split morning and midday
EvidenceGrade D
CategoryNootropics
The 3,000-person GEM trial found no effect on dementia prevention or cognitive decline, and meta-analyses in healthy adults find no cognitive enhancement. Only symptomatic use in existing dementia retains mixed support.
Ginkgo is in this directory as much for calibration as for recommendation: it is what a failed nootropic looks like after the good studies are in, and it is still one of the best-selling herbal supplements in the world.
The decisive evidence is unusually strong for a supplement, which is exactly the problem. The Ginkgo Evaluation of Memory study randomized over 3,000 older adults to 240 mg of the pharmaceutical-grade EGb 761 extract or placebo and followed them for a median of six years. Ginkgo prevented neither dementia nor cognitive decline — not overall, not in any subgroup. A companion analysis found no effect on the trajectory of memory, attention, or executive function. For healthy younger adults, meta-analysis of the enhancement literature reaches the same verdict: no convincing effect on memory, attention, or executive function.
What survives is narrow: in people who already have dementia, some European trials of EGb 761 report modest symptomatic benefits, and regulatory bodies in parts of Europe still permit that use. Tinnitus and peripheral-circulation claims sit on similarly mixed, low-quality evidence. None of this transfers to the healthy adult buying ginkgo at the pharmacy to stay sharp.
Ginkgo also carries a genuinely important interaction: it inhibits platelet-activating factor, and case reports of bleeding events — including alongside anticoagulants like warfarin — are numerous enough that surgeons routinely ask patients to stop it pre-operatively. A supplement with real bleeding risk and no demonstrated benefit in its flagship use is an easy call. The reason to keep the entry is the pattern it teaches: mechanism plausibility plus centuries of tradition plus early small positive trials can all coexist with a definitive null once someone funds the large, long study. Spend the money on sleep instead.
How it works
Standardized ginkgo extract contains flavone glycosides and terpene lactones with antioxidant, mild vasodilatory, and platelet-activating-factor-inhibiting actions. The proposed cognitive pathway — improved cerebral blood flow — is measurable, but has not translated into cognitive outcomes in large trials.
What the evidence supports
- Prevents dementia or cognitive decline GEM trial: definitive null over 6 years, n>3000D
- Enhances cognition in healthy adults meta-analyses find no effectD
- Improves symptoms in existing dementia mixed European trials of EGb 761C
Safety
Generally well tolerated as a standardised leaf extract, but bleeding risk matters with anticoagulants, antiplatelet drugs, or surgery; discuss stopping it with the surgical team. Avoid during pregnancy because safety is uncertain and bleeding or early-labor concerns have been reported. Raw ginkgo seeds, unlike the leaf extract, are toxic.
Reported side effects
- Headache
- GI upset
- Increased bleeding tendency
Interactions
- Do not combine with anticoagulants or antiplatelet drugs (warfarin, aspirin, clopidogrel) without medical supervision.
- May reduce the effectiveness of some anticonvulsants.
This guide is educational, not medical advice. Talk to a physician or pharmacist before starting any supplement, especially alongside prescription medication or a medical condition.
Common questions
- What does Ginkgo Biloba do?
- The best-selling brain herb in history — and the one whose biggest, best trials came back empty.
- Does Ginkgo Biloba actually work?
- Preliminary or weak evidence (grade D). The 3,000-person GEM trial found no effect on dementia prevention or cognitive decline, and meta-analyses in healthy adults find no cognitive enhancement. Only symptomatic use in existing dementia retains mixed support.
- How much Ginkgo Biloba should I take?
- The studied range is 120-240 mg/day of EGb 761 standardized extract, split into two doses. Start at the low end — more is not better once the effective range is covered.
- When should I take Ginkgo Biloba?
- With meals, split morning and midday — relevant only if you use it despite the evidence.
- Is Ginkgo Biloba safe?
- Generally well tolerated as a standardised leaf extract, but bleeding risk matters with anticoagulants, antiplatelet drugs, or surgery; discuss stopping it with the surgical team. Avoid during pregnancy because safety is uncertain and bleeding or early-labor concerns have been reported. Raw ginkgo seeds, unlike the leaf extract, are toxic. The most reported side effects are headache, gI upset, increased bleeding tendency.
- What should you not mix Ginkgo Biloba with?
- Do not combine with anticoagulants or antiplatelet drugs (warfarin, aspirin, clopidogrel) without medical supervision. May reduce the effectiveness of some anticonvulsants. Ask a pharmacist or physician before combining it with prescription medication.
References
Evidence review last updated