Ginkgo Biloba: What the Evidence Actually Shows, and How to Read the Label

Ginkgo biloba has been sold as a memory pill for decades, and the marketing has run ahead of the evidence. The honest picture is more useful: a few modest findings, several clear nulls, and one number on the label that decides whether the capsule in your hand can do anything at all. This guide grades each claim, gives the studied doses, and shows you how to read a ginkgo biloba label before you pay.

What Ginkgo Biloba Is, and Which Part of the Plant You Are Buying

Ginkgo biloba is an extract of the leaf of the ginkgo tree, one of the oldest living tree species. It is among the most studied herbs in the supplement aisle, and the part of the plant matters more than most buyers realize. The supplement is a leaf extract, not the seed. Raw or roasted ginkgo seeds are toxic and are a different product entirely. When a trial studies "ginkgo," it means the leaf.

Ginkgo Biloba Extract Is Not Leaf Powder

Two different products share the name. One is a ginkgo biloba extract, a refined concentrate with measured levels of the plant's active compounds. The other is plain leaf powder, dried leaf ground fine, with no guarantee of what is inside.

Nearly every trial used a specific standardized extract called EGb 761, and every dose below describes that form. (10) Unstandardized leaf powder carries no such trial behind it.

Everything the trials measured used a standardized extract. Plain leaf powder is a different product with a much thinner evidence base.

How This Guide Grades Every Claim

Most pages answer "what is ginkgo good for" with a list of maybes and no verdict. This guide grades each claim on four levels.

• Strong: multiple good trials agree.
• Modest: the effect is real but small, and reviews disagree on how much it matters.
• Weak: a signal exists, but it rests on one small or lower-quality study.
• Null: the best trials found no benefit. These are as useful as the hits.

Read the grade before the claim. A "supports memory" line and a trial that found nothing are not the same evidence.

Does Ginkgo Help Memory? The Honest Answer From the Trials

This is the claim that sells the bottle, so it deserves the hardest look. In healthy adults, the trials did not find the memory benefit the marketing promises. In people who already had cognitive trouble, there was a modest signal.

The Trial That Should Anchor the Category

The largest trial is the Ginkgo Evaluation of Memory study, or GEM. It followed 3,069 adults aged 75 and older who took 120 mg of EGb 761 twice daily for a median of 6.1 years. (1)

The result was a null. Ginkgo extract did not reduce the incidence of all-cause dementia (hazard ratio 1.12, 95 percent CI 0.94 to 1.33) or of Alzheimer disease (hazard ratio 1.16, 95 percent CI 0.97 to 1.39). (1) Most benefit listicles leave this number out.

In People Who Already Had Cognitive Impairment, a Modest Signal

A 2015 meta-analysis pooled 9 randomized trials and 2,561 people who already had cognitive impairment. In that group, EGb 761 at 240 mg per day stabilized or slowed decline in cognition, daily living, and global change over 22 to 26 weeks. (2)

Read the population note closely. The benefit was concentrated in people who already had impairment, not in healthy adults.

In Healthy Adults, No Attention Benefit

A 2025 network meta-analysis of 27 trials and 2,334 healthy adults found that no ginkgo extract significantly beat placebo for attention. (3) The strongest memory signal came from a Cistanche and ginkgo combination, not ginkgo alone.

Ginkgo Versus Bacopa on Working Memory

A 2026 network meta-analysis compared the two herbs across 29 trials and 2,107 people. High-dose Bacopa, at 600 mg per day or more, beat both high-dose ginkgo at 240 mg per day or more and low-dose ginkgo on working memory, with no difference in attention or processing speed. (4) Ginkgo is one option in a crowded category, and the working-memory data favor a different botanical.

In healthy adults, the best trials found no attention benefit from ginkgo extract. The memory claim does not survive the strongest evidence.

Ginkgo for Circulation: Real but Modest

If memory is where ginkgo disappoints, circulation is where it has its best support. The trials followed people with intermittent claudication and measured how far they could walk before pain stopped them.

The First Meta-Analysis: A 34-Meter Gain

A 2000 meta-analysis pooled 8 double-blind randomized trials of ginkgo extract. Pain-free walking distance improved by 34 meters (95 percent CI 26 to 43) compared with placebo. (5) The authors called the effect modest and of uncertain clinical relevance.

The Cochrane Review: No Clinically Significant Benefit

A 2010 Cochrane review looked at 11 trials and 477 participants. The effect on absolute claudication distance translated to about 64.5 meters (CI -1.8 to 130.7) at p = 0.06, and the authors found no evidence of clinically significant benefit. (6)

What the Disagreement Means

Two careful reviews, two numbers, one shared theme: any effect of ginkgo for circulation is small.

The signal is real and modest, and no one should expect it to restore a normal walking distance. Ginkgo's flavone and terpene lactones are the compounds credited with its antiplatelet effect, and separate mechanisms, including effects on cerebral blood flow, have also been described. (10) Plausible is not the same as large.

Tinnitus: The Evidence Is a Null

Ringing in the ears is one of the most common reasons people buy ginkgo, which makes the honest answer worth stating clearly.

A 2013 Cochrane review pooled 4 trials and 1,543 participants and found no evidence of benefit where tinnitus was the primary complaint. (7) A 2022 Cochrane update looked at 12 studies and 1,915 participants and concluded ginkgo may have little to no effect on tinnitus severity at 3 to 6 months, a mean difference of -1.35 on a 0 to 100 scale, at very low certainty. (8)

This is a null, stated plainly. Where the symptom is the main problem, the best evidence does not support buying ginkgo for it.

The One Surprise: Premenstrual Symptom Severity

Away from memory and circulation, there is one small positive finding worth reporting, and only as much of it as it deserves.

A 2009 single-blind randomized trial gave 85 women who completed it 40 mg of ginkgo leaf extract three times daily, from day 16 of the cycle to day 5 of the next. Overall symptom severity fell 23.68 percent on ginkgo against 8.74 percent on placebo (p < 0.001). (9) That is a real difference, but it is one small single-blind study. It needs replication before it moves from "interesting" to "established."

The Standardization Numbers That Decide If a Bottle Works

Here is the section most ginkgo pages skip, and the reason a standardized ginkgo extract beats plain leaf powder. A product is standardized when the maker guarantees measured levels of specific compounds.

Flavone Glycosides: 22 to 27 Percent

Flavone glycosides are one of the two main active groups in ginkgo. A properly standardized extract contains 22 to 27 percent flavone glycosides. (11)

Terpene Trilactones: 6 to 7 Percent

Terpene trilactones are the second active group, and the one most often linked to ginkgo's effects on blood flow. The standard is 6 to 7 percent terpene trilactones. (11)

The Quercetin-to-Kaempferol Ratio: The Authenticity Check

The quercetin-to-kaempferol ratio is the authenticity check used by analytical chemists. It tells a lab whether the material is genuine ginkgo leaf extract or a cheaper plant passed off as ginkgo. (11)

One in Five Products Failed the Check

In a study of the Croatian market, 20 percent of the sampled ginkgo products deviated from their label. Some had been replaced with Sophora japonica extract and spiked with genistein to fake the numbers. (11) Harvard Health points at the same problem from the other side: the FDA does not check the purity or potency of the ginkgo you buy. (16)

The label says "ginkgo." The flavone and terpene numbers are what tell you whether that is true.

Ginkgo Biloba Dosage: What the Trials Actually Used

There is no single ginkgo biloba dosage, because the trials used different doses for different goals. This table shows the dose each line of evidence tested.

Across the wider literature, studied doses have ranged from 80 to 720 mg per day, for two weeks to two years. (10) The GEM trial alone ran a median of 6.1 years. (1)

So how much ginkgo biloba should you take? The most commonly studied dose is 120 to 240 mg per day of a standardized extract. The label should let you confirm that without guessing. If a product cannot tell you how much extract is in a serving, it cannot be compared with any trial here.

How Long Before Ginkgo Works

No trial showed an overnight effect. The shortest structured trials that produced any result ran 22 to 26 weeks. (2) Studied periods have run from two weeks to two years, and GEM ran a median of 6.1 years. (1, 10)

Plan on weeks, not days. Give ginkgo a fair run at a studied dose before you judge it, and stop if you notice unusual bruising or bleeding.

How to Read a Ginkgo Label: A 6-Point Checklist

Take this to the aisle. Six questions decide whether a bottle is worth your money.

1. Is it a standardized extract? Look for the words "standardized extract," not plain leaf powder.
2. Are the flavone glycosides listed at 22 to 27 percent? If the number is missing, it is not standardized to the studied standard.
3. Are the terpene trilactones listed at 6 to 7 percent? This is the second number a real ginkgo extract declares.
4. Does the dose per serving land in the studied range? Compare it with 120 to 240 mg per day of extract.
5. Is there a third-party test or a certificate of analysis? With 20 percent of sampled products off-label, independent testing is your best guarantee that the label is honest. (11)
6. Is it leaf extract, not seed, and free of a proprietary blend? A blend hides the numbers, and the seed is not the supplement.

A standardized extract that prints the flavone and terpene numbers is the only version the trials studied.

Who Should Be Careful With Ginkgo

Ginkgo is generally well tolerated, but it is not for everyone. Check with a clinician if any of these apply.

• Pregnancy and breastfeeding. The National Center for Complementary and Integrative Health lists ginkgo as unsafe in pregnancy. (15)
• Anyone on a blood thinner. Ginkgo may increase bleeding risk when combined with anticoagulants such as warfarin. (15)
• Anyone facing surgery. Stop herbal medications 2 to 3 weeks before elective surgery. (17)
• Anyone taking aspirin or clopidogrel. These had the highest interaction rates with ginkgo in one large prescription review. (14)
• Anyone who notices unusual bruising or bleeding. Stop and talk to your clinician.

Raw or roasted ginkgo seeds are toxic. The supplement is a leaf extract, and only the leaf extract is the product discussed here.

Bleeding, Blood Thinners, and Surgery

The bleeding caution deserves its own section, because it is the most consistently reported interaction across the ginkgo literature.

Bleeding has been reported when warfarin is combined with ginkgo. (12) A systematic review of warfarin interactions lists ginkgo among the foods and herbs tied to a greater bleeding risk. (13)

A 2025 review of 2,647 prescriptions found that 12.94 percent had a ginkgo drug interaction. The highest rates were with clopidogrel and aspirin, at 2.61 percent each, and the interactions correlated with bleeding risk (odds ratio 1.08) and abnormal coagulation (odds ratio 1.49). (14) Ginkgo's antiplatelet effect is attributed to its flavone and terpene lactones, the same compounds that make it interesting in the first place. (10)

Stop herbal medications 2 to 3 weeks before elective surgery. The American Society of Anesthesiologists names ginkgo specifically.

If you take a blood thinner or face surgery, treat ginkgo as a medicine with a real interaction list, not a harmless leaf.

What We Recommend

These are the forms of ginkgo that fit the label standards this guide lays out: standardized leaf extracts that print their flavone and terpene numbers and land inside the studied dose range. We keep the list short on purpose, and we include one evidence-backed cognitive partner that carries its own trial support.

Frequently Asked Questions

References

1. DeKosky ST, et al. Ginkgo biloba for prevention of dementia: a randomized controlled trial. JAMA. 2008;300(19):2253-2262. PMID 19017911. https://pubmed.ncbi.nlm.nih.gov/19017911/
2. Tan MS, et al. Efficacy and adverse effects of ginkgo biloba for cognitive impairment and dementia: a systematic review and meta-analysis. J Alzheimers Dis. 2015;43(2):589-603. PMID 25114079. https://pubmed.ncbi.nlm.nih.gov/25114079/
3. Wang ZY, et al. Effects of natural extracts in cognitive function of healthy adults: a systematic review and network meta-analysis. Front Pharmacol. 2025;16:1573034. PMID 40213691. https://pubmed.ncbi.nlm.nih.gov/40213691/
4. Tiemtad P, et al. Comparative effects of Bacopa monnieri and Ginkgo biloba on cognitive functions: a systematic review and network meta-analysis. Phytomedicine. 2026;153:157915. PMID 41678913. https://pubmed.ncbi.nlm.nih.gov/41678913/
5. Pittler MH, Ernst E. Ginkgo biloba extract for the treatment of intermittent claudication: a meta-analysis of randomized trials. Am J Med. 2000;108(4):276-281. PMID 11014719. https://pubmed.ncbi.nlm.nih.gov/11014719/
6. Nicolaï SP, et al. From the Cochrane library: Ginkgo biloba for intermittent claudication. Vasa. 2010;39(2):153-158. PMID 20464671. https://pubmed.ncbi.nlm.nih.gov/20464671/
7. Hilton MP, et al. Ginkgo biloba for tinnitus. Cochrane Database Syst Rev. 2013;(3):CD003852. PMID 23543524. https://pubmed.ncbi.nlm.nih.gov/23543524/
8. Sereda M, et al. Ginkgo biloba for tinnitus. Cochrane Database Syst Rev. 2022;11(11):CD013514. PMID 36383762. https://pubmed.ncbi.nlm.nih.gov/36383762/
9. Ozgoli G, et al. A randomized, placebo-controlled trial of Ginkgo biloba L. in treatment of premenstrual syndrome. J Altern Complement Med. 2009;15(8):845-851. PMID 19678774. https://pubmed.ncbi.nlm.nih.gov/19678774/
10. Diamond BJ, Bailey MR. Ginkgo biloba: indications, mechanisms, and safety. Psychiatr Clin North Am. 2013;36(1):73-83. PMID 23538078. https://pubmed.ncbi.nlm.nih.gov/23538078/
11. Budeč M, et al. Verification of authenticity of Ginkgo biloba L. leaf extract and its products present on the Croatian market. Acta Clin Croat. 2019;58(4):672-692. PMID 32595253. https://pubmed.ncbi.nlm.nih.gov/32595253/
12. Fugh-Berman A. Herb-drug interactions. Lancet. 2000;355(9198):134-138. PMID 10675182. https://pubmed.ncbi.nlm.nih.gov/10675182/
13. Tan CSS, Lee SWH. Warfarin and food, herbal or dietary supplement interactions: a systematic review. Br J Clin Pharmacol. 2021;87(2):352-374. PMID 32478963. https://pubmed.ncbi.nlm.nih.gov/32478963/
14. Mai NTQ, et al. Impact of Ginkgo biloba drug interactions on bleeding risk and coagulation profiles. PLoS One. 2025;20(4):e0321804. PMID 40198642. https://pubmed.ncbi.nlm.nih.gov/40198642/
15. NCCIH. Ginkgo: Usefulness and Safety. https://www.nccih.nih.gov/health/ginkgo
16. Harvard Health. By the way, doctor: Ginkgo biloba: What's the verdict? Komaroff AL, 2018. https://www.health.harvard.edu/healthy-aging-and-longevity/by-the-way-doctor-ginkgo-biloba-whats-the-verdict
17. Poison Control. Ginkgo biloba: Risks and benefits. https://www.poison.org/articles/ginkgo-biloba-risks-benefits-181

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.