What it's actually good for
Ginkgo biloba is among the most heavily researched herbal supplements in existence — hundreds of trials, multiple systematic reviews, and one of the few herbs to get a proper multi-thousand-person federal prevention trial. The extract behind almost all of this research, EGb 761, is a standardized blend of flavonoid glycosides and terpene lactones (ginkgolides, bilobalide) with documented vasodilatory and antiplatelet activity. That mechanistic plausibility is why ginkgo has been tested for everything from memory to tinnitus to peripheral circulation. The results are a genuine mixed bag: modest, borderline signals for circulation and symptomatic cognitive support in people who already have decline, and a flat negative for the claim the marketing leans on hardest — preventing dementia in healthy people.
What the research says
Cognitive function in people with existing decline (Grade B). The Cochrane review by Birks & Grimley Evans (2009) found ginkgo's effects on cognitive impairment and dementia inconsistent across trials — some older, smaller studies showed benefit, but the larger, more rigorous ones showed weaker or no effect. The decisive test came from the NIH-funded GEM trial (DeKosky et al., 2008, JAMA): over 3,000 adults aged 75+, followed for a median of 6 years, with no benefit whatsoever for preventing dementia or slowing cognitive decline in people who started out healthy. NCCIH's summary is blunt: ginkgo "has not been shown to be effective for any of the conditions for which it has been studied" at the prevention level. What smaller trials still pick up is modest short-term improvement in processing speed, memory, and attention — in older adults who already have cognitive decline, not prevention in the healthy.
Peripheral circulation / intermittent claudication (Grade B, modest). A Cochrane review of 14 RCTs (739 participants) found ginkgo increased pain-free walking distance by roughly 64 meters over placebo after 24 weeks of treatment — but the pooled result across all time points landed just short of statistical significance (p = 0.06), and the reviewers flagged likely publication bias inflating the effect. Their stated conclusion: no clinically significant benefit for peripheral arterial disease, with supervised exercise therapy delivering far more improvement. This is real biological activity (vasodilation, reduced platelet aggregation) that hasn't clearly translated into a meaningful clinical outcome.
Tinnitus — despite the marketing, no. Ginkgo is widely sold as a tinnitus remedy, which is why it's worth flagging even though it isn't one of the claims graded above: a 2022 Cochrane update (Sereda et al.) found the evidence too uncertain to support any benefit, with effect sizes ranging from negligible to none.
How much, and which form
The clinically studied dose is 120-240 mg/day of standardized extract (EGb 761, standardized to 24% flavonoid glycosides and 6% terpene lactones), typically split into 2-3 doses. Raw leaf, tea, or unstandardized capsules aren't equivalent to what's been tested — and ginkgo seeds are a separate, toxic product (ginkgotoxin can cause seizures) that should be avoided entirely.
Safety & interactions
Ginkgo is generally well-tolerated; headache, dizziness, and GI upset are the most common complaints in trials. The real concern is bleeding risk — ginkgo's antiplatelet activity compounds with anticoagulants (warfarin), antiplatelet drugs, and even NSAIDs, and it should be discontinued at least two weeks before surgery. It may also interact with anticonvulsants and some diabetes medications through CYP enzyme pathways. This is informational, not medical advice — check with a clinician before starting, especially if you're on blood thinners.
How we picked the brand
A ginkgo product earns a spot when it's standardized to EGb 761-equivalent potency (24% flavonoid glycosides, 6% terpene lactones), states its extraction ratio clearly, and passes independent testing.