Ginkgo Biloba and Memory: Hype vs Evidence
Ginkgo biloba is often called a “memory herb”. It’s one of the best-selling herbal supplements in the world and one of the most heavily researched. That’s good news, because it means we have real answers. This guide looks at what the biggest studies found, and why the evidence doesn’t match the hype.
A living fossil
The ginkgo tree (Ginkgo biloba) is one of the oldest tree species on Earth. Its family dates back more than 200 million years, and it’s often called a “living fossil”. Its fan-shaped leaves turn a brilliant gold in autumn, and you’ll see ginkgo planted along streets and in parks in cities such as Melbourne, Canberra and Adelaide.
The tree is native to China, where its seeds have long been used in cooking and traditional medicine. Most modern supplements, though, are made from the leaves.
What’s in it?
Ginkgo leaves contain flavonoid glycosides and terpene lactones (ginkgolides and bilobalide). Most clinical research uses a standardised leaf extract, often called EGb 761, made to contain set amounts of these compounds. Researchers have proposed that they may affect blood flow and act as antioxidants, which is where the memory idea comes from.
Ginkgo for memory and dementia: Cochrane
The Cochrane Collaboration reviewed 36 trials of ginkgo for cognitive impairment and dementia (Birks & Grimley Evans, 2009). Most were small and short, but a handful were larger and longer.
The reviewers found that the evidence that ginkgo has a predictable and clinically significant benefit for people with dementia or cognitive impairment was inconsistent and unreliable. Earlier small trials were often positive, but the larger, better-designed trials tended to show no consistent benefit.
The GEM trial: can ginkgo prevent dementia?
The biggest single test of ginkgo was the Ginkgo Evaluation of Memory (GEM) study, published in JAMA in 2008 (DeKosky et al., 2008).
More than 3,000 adults aged 75 and over took either 120 mg of ginkgo extract twice a day or a placebo, and were followed for a median of about six years. At the end, the rate of dementia, including Alzheimer’s disease, was no different between the two groups. The researchers concluded that ginkgo at this dose was not effective in reducing dementia in older people.
It’s rare for a herbal question to be tested in such a large, long trial. That’s why GEM is so important, and why its result carries a lot of weight.
Ginkgo and tinnitus
Ginkgo is also often suggested for tinnitus, a ringing or buzzing in the ears. A 2022 Cochrane review looked at the evidence (Sereda et al., 2022). It found that ginkgo may have little or no effect on how loud or bothersome tinnitus is. The evidence was rated as low or very low certainty, so the reviewers couldn’t be confident either way.
Why does the “memory herb” idea persist?
Ginkgo’s reputation was built partly on early small studies, which are more likely to show positive results by chance. It also has a great story: an ancient tree that outlived the dinosaurs. But when researchers ran bigger and better trials, the effects largely disappeared. This is a common pattern in health research, and a useful reminder to look at the strongest evidence, not just the first.
If you’re worried about your memory or someone else’s, talk to your GP. Memory changes can have many causes, some of them treatable.
Ginkgo as a tea
Ginkgo leaf is sometimes enjoyed as a mild herbal tea:
- Use about 1 teaspoon of dried leaf per cup.
- Steep in just-boiled water for 5–10 minutes.
- It has a light, slightly grassy and nutty flavour, and blends well with green tea or mint.
Note that clinical trials used standardised extracts, not tea, so a cup isn’t comparable to the doses studied.
Who should take care?
Ginkgo may increase the risk of bleeding, especially in people taking blood-thinning medicines (such as warfarin), antiplatelet medicines (such as aspirin or clopidogrel) or some anti-inflammatories. Stop it before surgery or dental procedures, and tell your doctor. Raw or roasted ginkgo seeds can be toxic in large amounts and shouldn’t be eaten in quantity. Ginkgo isn’t recommended in pregnancy. Always check with your pharmacist if you take regular medication.
The bottom line
Ginkgo biloba is a remarkable tree, and its leaves have been studied more than most herbs. That research gives a fairly clear answer: big, well-run trials haven’t found that ginkgo protects memory or prevents dementia, and its effect on tinnitus is uncertain. Admire the tree, enjoy a cup if you like the taste, and be sceptical of memory-boosting claims.
This article is general information only and is not medical advice. It is not about any specific product. Talk to your GP or pharmacist about your own health.
References
- Birks J, Grimley Evans J. Ginkgo biloba for cognitive impairment and dementia. Cochrane Database Syst Rev. 2009. https://pubmed.ncbi.nlm.nih.gov/19160216/
- DeKosky ST, et al. Ginkgo biloba for prevention of dementia: a randomized controlled trial. JAMA. 2008. https://pubmed.ncbi.nlm.nih.gov/19017911/
- Sereda M, et al. Ginkgo biloba for tinnitus. Cochrane Database Syst Rev. 2022. https://pubmed.ncbi.nlm.nih.gov/36383762/
