Ginkgo Biloba for Memory: What Large Trials Found and Bleeding Cautions
What the large GEM trial and a 2026 Cochrane review found for ginkgo and memory, plus the bleeding, pregnancy and medicine cautions to know before asking a clinician.
Content last updated . This page has not been medically reviewed.
What is Ginkgo biloba good for?
What the body uses it for, and how strong the evidence is. A normal job in the body is not proof that extra supplements add benefit; each card says which.
Dementia prevention in older adults
Preliminary or mixedIn the largest prevention trial (3,069 adults aged 75 or older), ginkgo extract did not lower the chance of dementia or Alzheimer disease compared with placebo.
Supplements: No benefit shown for preventing dementia in the GEM trial and two other large studies noted by NCCIH.
Dementia symptoms
Preliminary or mixedA 2026 Cochrane review found low-certainty evidence of small to moderate benefits at six months in people who already have dementia.
Supplements: Low-certainty and inconsistent; applies to people with dementia, not to healthy adults.
Mild cognitive impairment
Preliminary or mixedCochrane found ginkgo probably has little or no effect on global status, thinking or daily activities at six months in mild cognitive impairment.
Supplements: Moderate-certainty evidence of little or no effect.
Memory and thinking in healthy adults
Not enough evidenceIt is uncertain whether ginkgo affects thinking in healthy people, and much of the research is low quality.
Supplements: Insufficient evidence for healthy adults.
Subjective memory complaints
Not enough evidenceIn people with memory complaints, Cochrane could not tell whether ginkgo improves overall status at six months (very low certainty).
Supplements: Very low-certainty evidence.
Tinnitus and heart-disease prevention
Not enough evidenceNCCIH says research suggests ginkgo does not help prevent heart disease, treat high blood pressure or relieve tinnitus.
Supplements: No benefit shown in the NCCIH summary.
Connected topics
Open a group to see how each topic connects and how strong the evidence is.
Body systems (1)
- Brain & FocusPreliminary or mixed
Ginkgo extract has been tested in dementia and mild cognitive impairment. Results are mixed (small benefit in dementia, little or none in mild cognitive impairment; no prevention effect).
Body parts (1)
- BrainPreliminary or mixed
Studies examine ginkgo extract for thinking and dementia; results are mixed and do not show prevention.
Conditions & symptoms (3)
- Alzheimer'S DiseasePreliminary or mixed
In the GEM trial, ginkgo extract did not reduce Alzheimer disease in adults aged 75 or older.
- Mild Cognitive DisorderPreliminary or mixed
Cochrane found ginkgo probably has little or no effect at six months; GEM found no effect on progression to dementia.
- TinnitusPreliminary or mixed
NCCIH says research suggests ginkgo does not relieve tinnitus.
Documented risks and interactions (4)
- Bleeding risk with blood thinners. Ginkgo may increase the risk of bleeding, especially in people taking anticoagulant drugs such as warfarin.
- Pregnancy and breastfeeding caution. Ginkgo may be unsafe in pregnancy and, near delivery, might cause early labor or extra bleeding. Little is known about breastfeeding.
- Side effects. The most common side effects are dizziness, stomach or gut upset and headache. In GEM the side-effect profiles of ginkgo and placebo were similar.
- Fresh seeds and raw plant are toxic. Fresh ginkgo seeds are toxic if eaten, and serious effects have followed roasted seeds or crude plant material. Leaf extract is a different product.
Evidence labels: no good evidence of benefit, mixed, insufficient evidence, low-certainty.
What large trials and reviews found
| Question | What the source found | Label |
|---|---|---|
| Preventing dementia in older adults | The Ginkgo Evaluation of Memory (GEM) trial gave 3,069 adults at five US medical centers aged 75 or older (normal thinking or mild cognitive impairment) a 120 mg extract twice a day or placebo, median follow-up 6.1 years. Ginkgo was not effective in reducing dementia or Alzheimer disease. [2] | No good evidence of benefit (study amounts are not advice) |
| Mild cognitive impairment, treatment | Cochrane (2026; 82 studies, 10,613 people overall): in mild cognitive impairment ginkgo probably has little or no effect at six months on global status, cognition or daily activities. [3] | No good evidence of benefit |
| Dementia, treatment of symptoms | The same review found low-certainty evidence of small to moderate benefits at six months. [3] NCCIH describes this evidence as inconsistent. [1] | Mixed |
| People with memory complaints | Cochrane: the authors were unsure whether ginkgo improves global clinical status at six months. [3] | Insufficient evidence |
| Healthy adults | NCCIH says it is uncertain whether ginkgo products affect thinking in healthy people, and much of the research is low quality. [1] A broader review of nine marketed ingredients (including ginkgo) called the science low certainty. [4] | Insufficient evidence |
These groups differ. The GEM result is about preventing dementia in people aged 75 or older, not about improving memory in a student or office worker. Likewise, symptom trials in people with dementia do not show that a healthy person will notice better memory.
Memory changes need a clinician first
If memory problems are new, getting worse or affecting daily life, see a clinician before trying a supplement. See mild cognitive impairment and dementia and memory changes: when to get help. Supplements are not approved by the FDA before sale, according to NCCIH, and contents vary; see quality testing and certifications.Frequently asked questions
Does ginkgo improve memory?
Large trials and reviews do not show a reliable benefit for prevention or for mild cognitive impairment. [2][3]
What did the GEM trial find?
In 3,069 adults aged 75 or older followed for a median 6.1 years, ginkgo extract did not reduce dementia compared with placebo. [2]
Is ginkgo safe with blood thinners?
NCCIH says ginkgo may raise bleeding risk in people on anticoagulants such as warfarin. Ask the prescriber or a pharmacist. [1]
Can I use ginkgo in pregnancy?
NCCIH says it may be unsafe in pregnancy and could cause early labor or extra bleeding near delivery. [1]
Does ginkgo help dementia symptoms?
The 2026 Cochrane review found low-certainty evidence of small to moderate benefits at six months, and NCCIH calls the evidence inconsistent. [3][1]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Bleeding and medicine cautions
- Blood thinners. NCCIH says ginkgo may increase the risk of bleeding in people taking anticoagulant drugs such as warfarin, and may interact with other drugs. [1] Do not start or stop anything without asking the clinician who prescribes your medicine.
- Surgery and procedures. Because of the bleeding reports above, tell your surgical team about every supplement. See supplements before surgery.
- Pregnancy. NCCIH says ginkgo may be unsafe in pregnancy and might cause early labor or extra bleeding during delivery if used near that time. [1] It says little is known about breastfeeding. See pregnancy and breastfeeding.
- Side effects. NCCIH lists dizziness, stomach upset and headache as the most common. In the Cochrane review, ginkgo may be linked to more adverse events at three months in people with memory complaints, but there was probably little difference at up to 12 months in dementia. [1][3] In GEM, side-effect profiles were similar to placebo. [2]
- Seeds and raw plant. NCCIH warns fresh ginkgo seeds are toxic and that serious effects have followed roasted seeds or crude plant material. Leaf extract is a different product. [1]
- Children, kidney and liver conditions. Not described in the sources we read for this page. Ask a clinician or pharmacist.
References
- National Center for Complementary and Integrative Health (US). Ginkgo. Read 2026-10-22.
- DeKosky ST et al. Ginkgo biloba for prevention of dementia: a randomized controlled trial (GEM). JAMA 2008. Read 2026-10-22.
- Wieland LS et al. Ginkgo biloba for cognitive impairment and dementia. Cochrane Database Syst Rev 2026. Read 2026-10-22.
- Crawford C et al. Dietary Supplement Ingredients for Optimizing Cognitive Performance Among Healthy Adults: A Systematic Review. J Altern Complement Med 2021. Read 2026-10-22.