Overview
Ginkgo biloba is one of the oldest living tree species and most widely used herbal supplements globally, particularly for cognitive function and circulation. While extensively researched, results are mixed - ginkgo shows moderate evidence for slowing dementia progression and improving peripheral arterial circulation (claudication) but disappointing results for cognitive enhancement in healthy adults despite widespread use for that purpose.
Critical safety note: Ginkgo has antiplatelet (blood-thinning) effects, necessitating caution with blood thinners and discontinued before surgery.
Primary applications focus on dementia and cognitive decline (moderate evidence for slowing progression, not prevention), peripheral arterial disease and claudication (good evidence), cognitive enhancement in healthy adults (weak evidence despite marketing), tinnitus and vertigo (mixed, mostly negative evidence), and general circulation support.
Evidence quality is moderate for dementia progression and claudication, weak for healthy adult cognitive enhancement, insufficient for tinnitus.
Safety concerns include bleeding risk due to antiplatelet effects, necessitating caution with blood thinners and discontinuation before surgery, though otherwise well-tolerated at typical doses (120-240 mg standardized extract daily).
What it means
Ancient tree, massively popular supplement, but evidence is disappointing for healthy brains. Works for: slowing dementia (not preventing), improving walking distance with circulation problems (claudication). Doesn't work for: boosting memory in healthy people (despite marketing). CRITICAL: Blood-thinning effects - stop 2 weeks before surgery. Typical dose: 120-240 mg standardized extract (24% flavonoids, 6% terpenes) daily.
Evidence Reality Check, Standardization, and Bleeding Risk
What it means
The ginkgo paradox: extensively researched with mostly negative results for healthy adults, yet remains bestselling "brain supplement." Marketing > science here.
Active compounds: Flavonoid glycosides (quercetin, kaempferol, isorhamnetin derivatives - typically 22-27% in standardized extracts) provide antioxidant effects. Terpene lactones (ginkgolides A, B, C, J and bilobalide - typically 5-7%) contribute to PAF (platelet-activating factor) inhibition and neuroprotection. The combination creates ginkgo's effects.
Dementia and Cognitive Decline
For dementia and age-related cognitive decline, this is ginkgo's better-supported application (though results still mixed). Meta-analyses suggest ginkgo (120-240 mg daily for 6-12+ months) might modestly slow cognitive decline in existing dementia or mild cognitive impairment, though effects are small. European research more positive than US trials.
Ginkgo doesn't prevent dementia - major US trial (GEM study) found ginkgo didn't prevent dementia in healthy elderly, highlighting distinction between prevention vs slowing existing decline.
What it means
If you already have dementia/MCI: ginkgo might slow decline a bit (European research more positive). If you're healthy: ginkgo won't prevent dementia (major US trial confirmed this).
Healthy Adult Cognitive Enhancement (Weak Evidence)
For cognitive enhancement in healthy adults, evidence is disappointing despite widespread use. Most well-designed trials in healthy young or middle-aged adults show minimal to no improvements in memory, attention, or cognitive performance. A systematic review concluded ginkgo doesn't enhance cognition in healthy people. User reports of benefits likely reflect placebo effects or confirmation bias.
What it means
Systematic review verdict for healthy adults: doesn't work. Most rigorous trials show zero cognitive benefit. If you feel smarter on ginkgo, that's probably placebo (which is real, but not the herb).
Claudication (Good Evidence)
For peripheral arterial disease and intermittent claudication (leg pain from poor circulation), ginkgo (120-160 mg daily) for 12-24 weeks significantly increases walking distance and reduces pain in claudication patients. Mechanisms involve improved blood flow and reduced inflammation.
What it means
Best application: if your legs hurt when walking due to poor circulation (claudication), ginkgo actually works. Increases pain-free walking distance significantly.
Tinnitus and Vertigo (Mostly Negative)
For tinnitus and vertigo, traditional use is extensive but research is very mixed. Some older studies suggested benefits, recent larger trials show minimal effects. A systematic review found insufficient evidence to support ginkgo for tinnitus. Anecdotal reports of benefits exist but placebo response is strong for tinnitus.
Standardization and Dosing
Standardization critical: Look for products standardized to 24% flavonoid glycosides and 6% terpene lactones (EGb 761 specification). Generic "ginkgo leaf" products without standardization have unpredictable potency.
Dosing: Dementia/cognitive decline: 120-240 mg standardized extract (24% flavonoid glycosides, 6% terpene lactones) daily, divided into 2-3 doses. Peripheral vascular disease: 120-160 mg daily. Cognitive enhancement attempts (despite weak evidence): 120-240 mg daily. Effects take weeks to months - not acute.
Safety and Bleeding Risk
Bleeding risk and safety: Ginkgo inhibits platelet-activating factor (PAF) creating antiplatelet effects - increased bleeding risk. While serious bleeding is rare, documented cases exist. Discontinue ginkgo 2 weeks before surgery. Use very cautiously (or avoid) with anticoagulants (warfarin, heparin) or antiplatelet drugs (aspirin, clopidogrel).
What it means
Blood-thinning is real, not theoretical. Cases of serious bleeding exist (rare but documented). Always tell your surgeon you're taking ginkgo - stop 2 weeks pre-op minimum.
Other side effects: Headache (occasional), GI upset or diarrhea (mild), dizziness (rare), and allergic skin reactions (rare, sometimes from ginkgolic acids which should be removed in quality extracts - check for <5 ppm ginkgolic acids).
Contraindications: Bleeding disorders, upcoming surgery (discontinue 2 weeks prior), anticoagulant therapy (use very cautiously with medical supervision), pregnancy (insufficient safety data), epilepsy (might lower seizure threshold in some cases).
Drug interactions: Blood thinners (additive effects), some antidepressants, diabetes medications (might affect blood sugar), and drugs metabolized by CYP450 enzymes (ginkgo has complex effects on various CYP enzymes).
Ginkgo biloba is an extensively researched herb with moderate evidence for slowing dementia progression and improving claudication, weak support for healthy adult cognitive enhancement despite marketing, and important antiplatelet bleeding risk requiring surgical precautions and blood thinner vigilance.
References
DeKosky ST, Williamson JD, Fitzpatrick AL, et al. Ginkgo biloba for prevention of dementia: a randomized controlled trial. JAMA. 2008;300(19):2253-2262.
Birks J, Grimley Evans J. Ginkgo biloba for cognitive impairment and dementia. Cochrane Database Syst Rev. 2009;(1):CD003120.