Ginkgo Biloba

Ginkgo biloba is the leaf extract of the maidenhair tree, one of the oldest living tree species on Earth, and one of the most-studied botanicals in Western and traditional medicine. The supplement that matters is not raw leaf powder but a concentrated, standardised extract — and almost the entire body of credible research used a single material: EGb 761, a leaf extract standardised to 24% flavonol (flavone) glycosides and 6% terpene lactones (the ginkgolides and bilobalide). That 24%/6% ratio is the most important specification in the category. A bottle labelled '24% / 6%' resembles what the trials tested; a bottle that just says 'Ginkgo Biloba 500 mg' of unstandardised leaf is a different product that happens to share the name.

The active compounds fall into two groups. The flavonol glycosides are antioxidant flavonoids that scavenge free radicals and support the vascular lining. The terpene lactones — ginkgolides A, B, C and bilobalide — are the more pharmacologically distinctive fraction, with ginkgolide B in particular acting as a platelet-activating-factor (PAF) antagonist that influences blood flow and platelet behaviour. A serious ginkgo extract is also purified to remove ginkgolic acids, naturally-occurring compounds in the leaf that can be allergenic at high concentrations; the cleanest products document a low limit (e.g. <1 ppm).

The honest framing every buyer deserves: ginkgo's real, replicated benefit is as a SYMPTOMATIC support at the studied 120-240 mg/day dose — modest improvements in memory and cognitive function in people with dementia, and modest improvements in walking distance in people with poor leg circulation. What it has NOT been shown to do is prevent cognitive decline in healthy people. The large, six-year Ginkgo Evaluation of Memory (GEM) Study found 240 mg/day ginkgo no better than placebo at preventing dementia. Buy ginkgo for what it does; ignore the 'prevents Alzheimer's' marketing.

Ginkgo's two compound classes drive two overlapping mechanisms: circulation and neuroprotection. On circulation, the terpene lactones — especially ginkgolide B — antagonise platelet-activating factor (PAF), which reduces platelet aggregation and supports microvascular blood flow; the flavonol glycosides relax vascular tone and protect the endothelium. The net effect is modestly improved peripheral and cerebral perfusion. This is the mechanism behind the one clearly non-cognitive benefit: in Pittler & Ernst 2000 (PMID 11014719), a meta-analysis of eight RCTs, standardised ginkgo (120-160 mg/day) increased pain-free walking distance in people with intermittent claudication by about 34 metres versus placebo — real, if modest.

On cognition, ginkgo's flavonoids are antioxidants that buffer oxidative stress in neural tissue, and bilobalide appears to have neuroprotective and mitochondrial-supportive effects. In dementia populations, standardised EGb 761 produced small but measurable benefits: Le Bars 1997 (PMID 9343463, JAMA) randomised Alzheimer's and multi-infarct dementia patients to 120 mg/day for 52 weeks and saw modest cognitive (ADAS-Cog) and functional gains versus placebo. Herrschaft 2012 (PMID 22459264) confirmed and extended this at the higher 240 mg/day dose over 24 weeks, improving both cognition (SKT) and the neuropsychiatric symptoms (NPI) that often accompany dementia — a meaningful finding for caregiver-relevant outcomes.

The crucial counterweight is prevention. It is tempting to assume that a herb which modestly helps an impaired brain must also protect a healthy one, but that assumption failed its biggest test. The Ginkgo Evaluation of Memory (GEM) Study (DeKosky 2008, PMID 19017911, JAMA) followed 3,069 older adults — cognitively normal or with mild cognitive impairment — on 240 mg/day EGb 761 versus placebo for a median of about six years. Ginkgo did NOT reduce the incidence of dementia or Alzheimer's disease, and did not slow overall cognitive decline. So the mechanistic story supports symptomatic use at the studied dose, not prevention in healthy people — and that is exactly how an honest buyer should frame it.