Ginkgo biloba — The Vascular Flavonoid
Ginkgo biloba is a botanical extract rich in flavonoids and terpenoids, traditionally used to improve blood flow and cognitive function. While it exhibits antioxidant and vasodilatory properties, large-scale human trials have largely failed to demonstrate efficacy in preventing dementia or cognitive decline, limiting its relevance as a core longevity intervention.
Mechanism of Action
Ginkgo biloba extract contains flavone glycosides (e.g., quercetin, kaempferol) and terpene lactones (ginkgolides, bilobalide). It acts primarily as a vasodilator and antioxidant, improving cerebral and peripheral blood flow by stimulating the release of nitric oxide and inhibiting platelet-activating factor (PAF). It also scavenges reactive oxygen species (ROS), protecting mitochondrial function and reducing oxidative stress in endothelial and neuronal cells. Additionally, it may modulate neurotransmitter systems, though its precise mechanisms in human neuroprotection remain debated.
Human Trial Evidence
Extensively studied in humans, primarily for cognitive decline and dementia prevention. The landmark Ginkgo Evaluation of Memory (GEM) study, a large randomised controlled trial, found that 120 mg twice daily did not reduce the overall incidence rate of dementia or Alzheimer's disease in elderly adults. Subsequent analyses also showed no effect on slowing cognitive decline in older adults with normal cognition or mild cognitive impairment. Evidence for longevity or lifespan extension in humans is lacking.
Dosing Protocol
120–240 mg/day of standardised extract (e.g., EGb 761), typically divided into two doses. Best taken with meals. Standardised extracts should contain 24% flavone glycosides and 6% terpene lactones.
Safety & Contraindications
Generally well-tolerated, but can increase bleeding risk due to its antiplatelet effects. Contraindicated in individuals taking anticoagulants (e.g., warfarin, apixaban) or antiplatelet drugs (e.g., aspirin, clopidogrel). May cause mild gastrointestinal upset, headaches, or allergic skin reactions. Should be discontinued at least two weeks prior to surgery.