Flavoglycosides
On supplement labels, 'flavone glycosides' / 'flavoglycosides' almost always refers to the 24%-flavone-glycoside specification of the standardised Ginkgo biloba extract EGb761 (Ginkgold, Tebonin, Gincosan). Every meaningful flavoglycoside-based claim is a ginkgo claim. The most rigorous trial — the 6-year GEM JAMA 2008 trial in 3,069 elderly adults — was NEGATIVE for dementia prevention and cognitive decline. Modest effects on intermittent claudication; bleeding-risk safety signal in case reports.
Quick decision guide
May help most
Adults with intermittent claudication (peripheral artery disease) who can't or won't pursue exercise therapy alone. Not justified for cognitive support given the GEM trial.
Common dosing range
120–240 mg/day standardised EGb761 extract (24% flavone glycosides, 6% terpene lactones).
When to expect effects
8–12 weeks for any vascular benefit; the cognitive claim is essentially refuted at all timepoints.
Watch out for
Increased bleeding risk in case reports — stop 1–2 weeks before any surgery; avoid with warfarin, DOACs, aspirin, or other antiplatelet/anticoagulant drugs.
Evidence snapshot
What is it
Is it worth it for you?
Use this as a quick fit check, not a diagnosis.
Worth considering if…
Probably skip if…
Evidence at a glance
| Goal | Effect | Best fit | Time |
|---|---|---|---|
Intermittent claudication (peripheral artery disease) Limited Evidence | +64 m pain-free walking distance vs placebo (Cochrane 2013, 14 RCTs) | Patients with documented PAD on optimal medical therapy who want an adjunct beyond exercise | 8–24 weeks in trials |
Tinnitus and vertigo Mixed Evidence | No consistent tinnitus benefit per Cochrane; modest vertigo signal in some EGb761 trials | Adults with vertigo of suspected vascular cause considering a short trial | 8–12 weeks of trial duration |
General antioxidant / circulation support in healthy adults Mixed Evidence | No reliable clinical-outcome benefit in healthy adults | None established | Not established |
Dementia prevention and cognitive decline (Alzheimer's, mild cognitive impairment) Weak Evidence | GEM: no reduction in dementia incidence (HR 1.12, 95% CI 0.94–1.33) and no slowing of cognitive decline over 6 years | None established — the definitive long-term RCT was null | 6 years of GEM follow-up showed no benefit at any timepoint |
Intermittent claudication (peripheral artery disease)
- Effect
- +64 m pain-free walking distance vs placebo (Cochrane 2013, 14 RCTs)
- Best fit
- Patients with documented PAD on optimal medical therapy who want an adjunct beyond exercise
- Time
- 8–24 weeks in trials
Tinnitus and vertigo
- Effect
- No consistent tinnitus benefit per Cochrane; modest vertigo signal in some EGb761 trials
- Best fit
- Adults with vertigo of suspected vascular cause considering a short trial
- Time
- 8–12 weeks of trial duration
General antioxidant / circulation support in healthy adults
- Effect
- No reliable clinical-outcome benefit in healthy adults
- Best fit
- None established
- Time
- Not established
Dementia prevention and cognitive decline (Alzheimer's, mild cognitive impairment)
- Effect
- GEM: no reduction in dementia incidence (HR 1.12, 95% CI 0.94–1.33) and no slowing of cognitive decline over 6 years
- Best fit
- None established — the definitive long-term RCT was null
- Time
- 6 years of GEM follow-up showed no benefit at any timepoint
Evidence for 4 uses
AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.
Intermittent claudication (peripheral artery disease)
Disease adjunctThe Cochrane review of 14 RCTs (n=739) of standardised ginkgo for intermittent claudication found ginkgo improved pain-free walking distance by approximately 64 m on average. This is real but modest — similar to what a supervised brisk-walking program achieves, and walking should be the first-line intervention. Reasonable as an adjunct in patients who can't or won't pursue exercise therapy alone, particularly when standard treatments (cilostazol, smoking cessation, lipid management) are already in place.
Bottom line: Modest, real walking-distance benefit. Use as an adjunct to optimal PAD care, not a substitute.
Tinnitus and vertigo
Supplement benefitStandardised ginkgo extract has been studied for tinnitus and vertigo. The Cochrane review (Hilton 2013) concluded there is no consistent evidence that ginkgo is helpful for primary tinnitus. Some smaller European trials of EGb761 in vertigo (especially of suspected vascular origin) showed modest benefit. The overall picture is mixed and not definitive for either indication.
Bottom line: Mixed evidence. Worth a short standardised-extract trial for vertigo; less so for pure tinnitus.
General antioxidant / circulation support in healthy adults
Mechanism onlyFlavone glycosides from ginkgo modulate endothelial nitric oxide, inhibit platelet-activating factor (via the terpene lactones, especially ginkgolides), and have antioxidant activity in vitro. Healthy adults supplementing standardised ginkgo have not shown reliable clinical-outcome benefits. The case for daily ginkgo in well people rests on mechanism rather than results.
Bottom line: Mechanism-based, no clinical outcomes in healthy people. Skip.
Dementia prevention and cognitive decline (Alzheimer's, mild cognitive impairment)
Supplement benefitThe Ginkgo Evaluation of Memory (GEM) trial — the largest, longest, best-controlled trial of standardised ginkgo for cognition — randomised 3,069 community-dwelling adults aged 75+ to EGb761 240 mg/day (the same 24% flavone glycoside / 6% terpene lactone specification used in earlier optimistic trials) or placebo, followed for a median of 6.1 years. The result was definitively negative for both primary endpoints: no reduction in dementia or Alzheimer incidence (HR 1.12), and no slowing of cognitive decline in the cognitive-function arm. The Cochrane review of ginkgo for dementia concludes the evidence for predictable clinical benefit is 'inconsistent and unconvincing.' The marketing of ginkgo as a memory or cognitive supplement is not supported by the highest-quality evidence.
Bottom line: Do not take ginkgo / flavoglycosides for memory or to prevent dementia. The best evidence says it doesn't work.
Evidence is mixed
Smaller earlier trials (especially in Europe with EGb761) reported modest cognitive improvements in dementia patients. The much larger, longer, methodologically stronger GEM trial and the Cochrane review of all trials together refute a clinically meaningful cognitive benefit.
How it works
How to take it
What to track
Bottom line: 120–240 mg/day standardised EGb761 with food. Stop before surgery and avoid in anyone on antiplatelets / anticoagulants.
3 commercial forms
Compare the main delivery options and what they’re best suited for.
EGb761 (Ginkgold, Tebonin, Gincosan)
RCT-grade standardThe Schwabe-pharmaceutical-grade standardised extract used in virtually every meaningful ginkgo RCT, including GEM. Specified at 24% flavone glycosides + 6% terpene lactones, with ginkgolic acids capped at <5 ppm. The only ginkgo form you should consider if you're going to use one.
Reference form for all clinical-trial evidence.
Other 24/6 standardised ginkgo extracts
Mass-market equivalentGeneric '24% flavone glycoside, 6% terpene lactone' products from various manufacturers. Quality and ginkgolic-acid content vary; third-party testing is more important here than for the named-brand EGb761-equivalent products.
Variable; brand-dependent.
Whole-leaf / non-standardised ginkgo
AvoidCrude ginkgo leaf powder or unstandardised extracts. Active-constituent content is unknown and ginkgolic-acid contamination can be high — these are the products most associated with hepatotoxicity, carcinogenicity concerns, and rare seizure reports. Do not use.
Unknown active content; safety concerns from contaminants.
Safety
Know the common side effects, key cautions, and who should avoid it.
Common side effects
Serious risks
Bleeding — case reports of subdural hematoma, intraocular hemorrhage, and post-surgical bleeding, especially in patients also on aspirin, warfarin, or undergoing surgery. Population-level RCTs show small or no increased bleeding at standard EGb761 doses, but the case-report signal is consistent enough to warrant pre-surgical discontinuation and avoidance with antiplatelets/anticoagulants.
Seizure threshold — rare case reports of seizures with ginkgo, possibly from contamination of crude extracts with ginkgotoxin (4'-O-methylpyridoxine) from ginkgo seeds. Standardised EGb761 extracts test below seizure-relevant ginkgotoxin levels; non-standardised whole-plant products are more concerning.
Hepatotoxicity from non-standardised products — crude ginkgo and unstandardised extracts can contain ginkgolic acids that are hepatotoxic and potentially carcinogenic. Standardised EGb761 has a ginkgolic-acid limit; cheap unstandardised products may not. Choose tested brands.
Who should avoid it
- People on warfarin, DOACs (rivaroxaban, apixaban, dabigatran), heparin, or daily aspirin / clopidogrel — bleeding-risk case reports.
- Anyone scheduled for surgery within 1–2 weeks — stop now.
- People with seizure disorders — rare case reports of lowered seizure threshold.
- Pregnant or breastfeeding women — insufficient safety data; ginkgolic-acid concerns.
- People taking SSRIs / SNRIs / MAOIs at high doses — case reports of serotonin syndrome.
Pregnancy & breastfeeding
Avoid in pregnancy and breastfeeding. Insufficient safety data, ginkgolic-acid concerns in non-standardised products, and theoretical bleeding-risk concerns make the risk/benefit ratio unacceptable.
Bottom line: Real bleeding-risk signal in case reports. Avoid with antiplatelets/anticoagulants; stop before surgery; use only standardised EGb761-equivalent products.
Interactions
Increased bleeding risk per case reports. Avoid the combination or use only with careful monitoring of INR (warfarin) and bleeding signs.
Additive antiplatelet effect with ginkgo's PAF-inhibitory terpene lactones. Bleeding-event case reports include subdural hematoma. Avoid the combination.
Case reports of serotonin syndrome with the combination. Mechanism uncertain. Monitor closely or avoid.
Possible reduction in seizure threshold from contaminating ginkgotoxin; possible CYP-mediated effects on anticonvulsant levels. Avoid in epilepsy patients.
Case report of coma in an Alzheimer patient on trazodone who started ginkgo, possibly via increased GABA-A activity. Avoid the combination.
Mixed in-vitro evidence for CYP induction or inhibition; small human studies inconsistent. Monitor narrow-therapeutic-index drug levels when starting/stopping ginkgo.
Food sources
| Food | Amount | %DV |
|---|---|---|
| Ginkgo biloba leaf (whole leaf, not used dietarily) | Not a food source — used as standardised extract supplement only | — |
| Ginkgo seeds (TCM 'bai guo') | Limited culinary use in East Asian cuisine; toxic if eaten in quantity | — |
Ginkgo biloba leaf (whole leaf, not used dietarily)
- Amount
- Not a food source — used as standardised extract supplement only
- %DV
- —
Ginkgo seeds (TCM 'bai guo')
- Amount
- Limited culinary use in East Asian cuisine; toxic if eaten in quantity
- %DV
- —
Choosing a product
What to look for on the label — and what to be skeptical of.
Look for…
Be skeptical of…
Frequently asked questions
What are flavoglycosides on my label?⌄
A standardization marker showing the extract contains the expected ratio of flavonoid glycosides, usually for ginkgo at 24%.
Are flavoglycosides the same as flavonoids?⌄
They are a subset: flavonoids attached to a sugar molecule.
References by claim
Dementia prevention and cognitive decline (Alzheimer's, mild cognitive impairment)
Intermittent claudication (peripheral artery disease)
Nicolaï et al. Cochrane, 2013 — Cochrane Database of Systematic Reviews (2013) link
Safety
Bent et al., 2005 — Journal of General Internal Medicine (2005) link
Tinnitus and vertigo
MSKCC About Herbs — Ginkgo biloba — Memorial Sloan Kettering Cancer Center (2024) link
Track Flavoglycosides with Pilora
Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.
Coming to App StoreDisclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.