Ginkgo biloba is best supported by evidence for improving cognitive function in people with dementia, reducing anxiety symptoms, and supporting blood circulation. It’s one of the most widely studied herbal supplements in the world, with over 60 bioactive compounds in its leaves. But the evidence is stronger for some uses than others, and a few popular claims don’t hold up at all.
How Ginkgo Works in the Body
Ginkgo’s effects come primarily from two groups of compounds: flavonoids, which make up about 24% of a standardized extract, and terpenoids, which account for about 6%. The flavonoids act as antioxidants, protecting cells from damage. The terpenoids do something more specific: they reduce the stickiness of blood platelets, which improves blood flow through small vessels. One compound in particular acts as a direct blocker of platelet-activating factor, a molecule that triggers clotting and inflammation.
These two mechanisms, antioxidant protection and better circulation, explain most of ginkgo’s effects. More blood reaching the brain means more oxygen and glucose for neurons. Less oxidative stress means less cellular damage over time. The terpenoids also appear to have direct protective effects on neurons in the hippocampus, the brain region responsible for memory and learning.
Cognitive Function and Dementia
This is where the strongest clinical evidence sits. A systematic review and meta-analysis published in Frontiers in Aging Neuroscience looked at ginkgo preparations for Alzheimer’s disease and found that patients taking ginkgo scored significantly higher on the Mini-Mental State Examination, a standard test of cognitive function, with an average improvement of about 3 points compared to control groups. That may sound modest, but in Alzheimer’s care, a 3-point shift on this scale represents a meaningful difference in daily functioning.
Patients in the ginkgo groups also showed better scores on daily living activities and vocabulary memory. The clinical effectiveness rate was about 23% higher in people taking ginkgo compared to controls, with benefits appearing after 3 to 9 months of consistent use. Importantly, the rate of adverse events was no different between ginkgo and control groups in these trials.
For healthy younger adults hoping ginkgo will make them sharper, the picture is less clear. Some studies show modest improvements in concentration and blood flow to the brain, but the dramatic cognitive benefits seen in dementia research don’t translate directly to people with normal brain function.
Anxiety Reduction
A randomized, double-blind, placebo-controlled trial tested ginkgo extract in people with generalized anxiety disorder. Participants taking a higher dose saw their anxiety scores on the Hamilton Anxiety Rating Scale drop by 14.3 points on average, compared to a 7.8-point drop in the placebo group. That’s nearly double the improvement. Even the lower-dose group saw a 12.1-point reduction. These results suggest ginkgo has a genuine calming effect that goes well beyond placebo, though it’s not widely prescribed for anxiety in most countries.
Blood Circulation and Vascular Health
Ginkgo has long been used for peripheral circulation problems, and there’s reasonable evidence to support this. In a secondary analysis from the large Ginkgo Evaluation of Memory Study, participants taking ginkgo experienced fewer peripheral vascular disease events (8% vs. 1.5% in the placebo group). The extract helps relax blood vessels, reduces inflammation in vessel walls, and has protective effects against atherosclerosis, the buildup of fatty plaques in arteries.
However, ginkgo did not reduce the incidence of coronary heart disease or stroke in that same study. So while it may help with circulation to the extremities, it’s not a substitute for standard cardiovascular prevention.
Tinnitus: A Common Claim That Doesn’t Hold Up
Ginkgo is frequently marketed for tinnitus (ringing in the ears), but the evidence doesn’t support this use. A Cochrane review examining four trials with 1,543 total participants found no evidence that ginkgo is effective when tinnitus is the primary complaint. In one trial of dementia patients who also had tinnitus, there was a small reduction in symptoms, but baseline tinnitus levels were already very low, and the practical significance of the improvement was unclear. If tinnitus is your main reason for considering ginkgo, the research suggests it won’t help.
What to Know About Dosage and Timing
Most clinical trials use standardized ginkgo leaf extract at doses of 120 to 240 mg per day, split into two or three doses. “Standardized” means the extract is concentrated to contain 24% flavonoids and 6% terpenoids. This matters because raw ginkgo leaves or unstandardized products can vary wildly in their active compound levels. When shopping for ginkgo supplements, look for products that list these percentages on the label.
Ginkgo is not a fast-acting supplement. The dementia trials measured outcomes at 3 to 9 months. A six-week supplementation study in healthy young men found only marginal improvements in physical performance and antioxidant capacity. If you’re going to try ginkgo, plan on at least 8 to 12 weeks of consistent daily use before evaluating whether it’s doing anything for you.
Bleeding Risk and Drug Interactions
Because ginkgo reduces platelet stickiness, it increases bleeding risk when combined with blood thinners or common pain relievers. Aspirin and clopidogrel show the highest interaction rates, each at about 2.6% in one comprehensive analysis. Celecoxib, loxoprofen, and even omeprazole (a common acid reflux medication) were also significantly associated with bleeding or abnormal clotting when taken alongside ginkgo.
If you take any blood-thinning medication, antiplatelet drug, or regular NSAIDs like ibuprofen, adding ginkgo could meaningfully increase your risk of bruising, nosebleeds, or more serious bleeding events. This interaction is one of the most well-documented risks of the supplement and applies to both prescription and over-the-counter medications.
Ginkgo Seeds Are Not the Same as Leaf Extract
Ginkgo supplements are made from leaves, but ginkgo seeds are eaten as food in parts of East Asia. These are not interchangeable. Raw ginkgo seeds contain a toxin called ginkgotoxin that is chemically similar to vitamin B6 and interferes with its function in the brain. This disrupts the balance between calming and excitatory brain signals, which can trigger seizures. As few as 10 cooked seeds eaten at once have caused acute poisoning in humans.
Symptoms of seed poisoning, including nausea, vomiting, confusion, and convulsions, typically begin 1 to 12 hours after ingestion. Cooking reduces but does not eliminate the risk, because ginkgotoxin is heat-stable. Unripe and uncooked seeds are the most dangerous and should never be eaten. None of this applies to standardized leaf extracts, which contain negligible amounts of this toxin.