Ginkgo (Ginkgo biloba)

Ginkgo has the ability to improve blood levels of nitric oxide, which improves circulation via the dilation of blood vessels ( 7 ). As a result, ginkgo may also be useful for treating various symptoms of sexual dysfunction by improving blood flow to those areas of the body. (HealthLine) Prescription for Herbal Healing ~ “Ginkgo also has powerful antioxidant properties in the brain…”. Ginkgo is used for memory loss and degenerative diseases in the brain.

Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.

1) Overview

What it is: Extract from the leaves of the Ginkgo biloba tree, often standardized to 24% flavone glycosides and 6% terpene lactones (commonly sold as EGb 761). NCBI+1
Common uses (marketed): “Memory/brain health,” dementia symptoms, peripheral circulation, tinnitus, anxiety, PMS, vertigo; evidence varies and is often inconclusive. NCCIH
Forms: Tablets/capsules (standardized extract), liquid extracts/tinctures; seeds (“ginkgo nuts”) are a food in some cuisines but can be toxic and are not recommended as a supplement source. NCBI+1

2) Mechanism of Action

Antioxidant & neuroprotective: Flavone glycosides scavenge free radicals; studies suggest protection against oxidative and ischemic neuronal injury. NCBI
Neurotransmitters: Evidence (mostly preclinical) for mild MAO inhibition, increased cholinergic transmission, and modulation of serotonin/dopamine signaling. NCBI
Vascular effects: Enhances endothelial nitric oxide and prostacyclin, promoting vasodilation; ginkgolides antagonize platelet-activating factor (PAF) (anti-platelet activity). NCBI
Other: Standardized extracts limit ginkgolic acids (potentially allergenic); quality control matters (see Red Flags). PMC

3) Dosage & Forms

Standardized extract (EGb 761): Typical clinical doses 120–240 mg/day, taken in 2–3 divided doses; many dementia trials used 240 mg/day for ≥24 weeks. NCBI+1
Standardization: Look for products declaring ~24% flavone glycosides, ~6% terpene lactones, and <5 ppm ginkgolic acids. PMC
Onset: Cognitive symptom trials generally evaluate after 4–6 months. Frontiers
Food/tea: Non-standardized teas or foods do not match clinical dosing used in trials. NCCIH

4) Safety & Side Effects

Common: Headache, GI upset, dizziness; generally well-tolerated in trials up to 6 years when using standardized leaf extract. NCCIH+1
Bleeding risk: Due to PAF antagonism, caution with anticoagulants/antiplatelets/NSAIDs; case reports and population data show higher bleeding risk with warfarin co-use. Stop 1–2 weeks before surgery is commonly advised. NCBI
Seizures: Avoid in epilepsy or seizure-prone individuals; ginkgotoxin (higher in seeds, also present in leaves) can lower seizure threshold. Do not eat raw/roasted seeds. Kuh University+1
Pregnancy/lactation: Avoid—possible increased bleeding and insufficient safety data. NCCIH
Diabetes: May affect glucose control; monitor if used. Mayo Clinic
Drug interactions (examples): Anticoagulants (warfarin), antiplatelets (aspirin, clopidogrel), NSAIDs; potential effects on CYP2C19/CYP3A4 are described but usually weak at ≤240 mg/day. Rare reports suggest risk of serotonin syndrome with other serotonergic agents. Discuss with your clinician/pharmacist. NCBI

5) Food Sources (if applicable)

Not a nutrient with dietary “sources.”
Ginkgo seeds (“nuts”) are eaten in some cuisines but pose toxicity risk (ginkgotoxin) and are not recommended as a supplement alternative. Kuh University

6) Practical Uses (What it may help with)

Evidence below reflects standardized extract unless noted.

Dementia symptoms (AD/vascular/mixed):
Mixed literature. Several meta-analyses and RCTs report modest improvements in cognition/activities of daily living at 240 mg/day, especially with neuropsychiatric symptoms; others find no clinically meaningful benefit. Dove Medical Press+2BioMed Central+2
Prevention of dementia / cognitive decline (in cognitively normal or MCI): Large, long-term RCTs (GEM) show no benefit at 120 mg twice daily. JAMA Network+1
Tinnitus: Overall not helpful vs placebo in most analyses. NCCIH
Peripheral arterial disease (intermittent claudication): Evidence does not show meaningful benefit. NCBI
Anxiety/PMS/vertigo: Some small trials suggest benefit, but evidence is limited/low quality. NCCIH+1
Stroke rehab / glaucoma / macular degeneration: Early or mixed signals; insufficient high-quality evidence for routine use. NCBI

Bottom line: Best-supported (still mixed) use is short-term symptomatic treatment in dementia at 240 mg/day; not effective for preventing dementia. Dove Medical Press+1

7) Cautions / Red Flags

Quality/adulteration: Adulteration of ginkgo supplements with added rutin/quercetin/kaempferol to “fake” the 24% flavone glycosides is documented. Prefer reputable brands with third-party testing (e.g., USP, NSF). PMC
Regulation: In the U.S., dietary supplements are not FDA-approved for safety/efficacy before marketing; potency and composition can vary. NCCIH
Seeds are toxic: Avoid raw/roasted ginkgo seeds due to ginkgotoxin and seizure risk. Kuh University

8) References & Links

NCCIH (NIH): Ginkgo: Usefulness and Safety (updated Feb 2025). NCCIH
StatPearls (NCBI Bookshelf): Ginkgo Biloba (mechanisms, dosing, safety). NCBI
JAMA – GEM Trial: Ginkgo biloba for prevention of dementia (no benefit). JAMA Network
JAMA – Cognitive decline analysis: Ginkgo biloba for preventing cognitive decline in older adults (no benefit). JAMA Network
Meta-analyses/reviews on dementia symptoms:
- Gauthier & Schlaefke 2014: EGb 761 symptomatic benefit at 120–240 mg/d (systematic review). Dove Medical Press
- Weinmann 2010: Effect sizes moderate; clinical relevance uncertain. BioMed Central
- Frontiers Pharmacol 2020: Benefit more likely at 240 mg/day over ≥24 weeks. Frontiers
Mayo Clinic: Safety/interaction overview (bleeding, seizures, diabetes, surgical stop). Mayo Clinic
Adulteration evidence: 2D-COS/UV-Vis screening shows widespread adulteration in commercial products. PMC
General ODS portal: NIH Office of Dietary Supplements fact sheet index. Office of Dietary Supplements
WebMD (interaction overview for lay readers): Drug–supplement interactions. WebMD

Quick Take for Safe Use

If you and your clinician decide to try ginkgo, use a reputable, standardized extract at 240 mg/day (divided) for at least 24 weeks before judging effect; avoid if you have a bleeding disorder, take blood thinners/NSAIDs, are pregnant, or have seizures; never consume seeds; and choose third-party tested products to reduce adulteration risk. PMC+3Frontiers+3