Ginkgo extract labels: Why leaf source does not establish the standardized amount

Knowing that a ginkgo product comes from the leaf tells you where the raw material started. It does not tell you how much of any specific compound is in each capsule. The National Center for Complementary and Integrative Health (NCCIH) says ginkgo leaf, usually as an extract, is the most commonly used form of ginkgo, so “made from ginkgo leaf” is a description many products can share, and it cannot separate one from another. The amount question is answered, if it is answered at all, by a different part of the label: a stated standardization, and the milligrams it applies to.

This guide explains how to read those two pieces together, walks through a hypothetical example, and marks where a label question ends and a conversation with a pharmacist or prescriber should begin.

What “leaf source” tells you, and what it leaves out

“Leaf” answers one question: which part of the plant was used? That matters, because NCCIH warns that fresh ginkgo seeds are toxic and that serious side effects have occurred with roasted seeds and the crude plant. So “leaf” is a useful starting point.

It is only a starting point. A label can say “leaf” and describe any of these:

Ground leaf (powder). The leaf itself, with no refining.
A dry extract. Leaf that has been put through an extraction process, which concentrates some compounds.
A refined, standardized extract. An extract made to a stated composition.

A 2019 laboratory study of ginkgo supplements (Arruda Frommenwiler and colleagues, Journal of Ethnopharmacology) listed products from several countries, including the UK, Spain, Denmark and the US. Its product table described some as ginkgo leaf powder, some as refined ginkgo dry extract, and some as other types of dry extract. All of them could truthfully be called “from ginkgo leaf.” They are not the same thing in a capsule.

What “standardized” is meant to say

A standardized extract is one made to a stated composition. For ginkgo, the reference point in the research literature is an extract called EGb 761. A 2003 summary in Drugs in R&D describes a standardized ginkgo leaf extract as containing approximately 24% flavone glycosides and 6% terpene lactones. That is where the shorthand “24/6” on some labels comes from.

Even published descriptions of that one extract are not identical. A 2013 review of EGb 761 (Serrano-García and colleagues, doi:10.1155/2013/495703) gives ranges in its abstract, 24 to 26% flavonoid glycosides and 6 to 8% terpene lactones, and slightly different figures again in its main text. That is not a contradiction so much as a reminder that “standardized” is a stated specification, and the number you see depends on whose specification it is.

The percentage only means something when it is attached to an amount. Twenty-four percent of 120 milligrams is a different quantity than twenty-four percent of 60 milligrams.

Four label phrases that sound alike and answer different questions

“Ginkgo biloba leaf, 120 mg.” Tells you the plant part and a weight. It does not tell you whether that weight is powder or extract, and it states no percentage of anything.
“Ginkgo biloba leaf extract, 120 mg.” Tells you the weight of an extract. Without a stated standardization, it does not tell you what the extract contains.
“Standardized to 24% flavone glycosides and 6% terpene lactones.” States a composition. Paired with an extract weight, it lets you work out the amount of each group per serving.
“Equivalent to 6,000 mg of leaf.” Describes how much leaf was used to make the extract at the start. It is a statement about the input, not about what the finished extract holds.

A worked reader scenario: three bottles, one question

This is a hypothetical illustration. The products and numbers are invented to show the arithmetic, not taken from any real label, and the example says nothing about how any product performs.

Imagine you are comparing three ginkgo bottles. All three say they are made from Ginkgo biloba leaf. You want to know which label tells you how much of the standardized compounds you would get per capsule.

Bottle A: “Ginkgo biloba leaf extract, 120 mg, standardized to 24% flavone glycosides and 6% terpene lactones.” The math is 120 mg x 0.24 = 28.8 mg of flavone glycosides and 120 mg x 0.06 = 7.2 mg of terpene lactones per capsule, if the label is accurate.
Bottle B: “Ginkgo biloba leaf, 120 mg.” There is no percentage and no statement that this is an extract, so there is nothing to multiply. You cannot work out an amount of either compound group from this line.
Bottle C: “Ginkgo biloba leaf extract, 120 mg (equivalent to 6,000 mg of leaf).” The “equivalent to” figure means 50 parts of leaf per part of extract (6,000 / 120). That describes the starting material. It still gives you no percentage of flavone glycosides or terpene lactones in the finished extract.

What the example shows. Only Bottle A states enough for you to check the numbers. Leaf source was identical across all three, and it did not decide which label answered your question.

What it does not show. It does not rank the bottles, and it does not say Bottle A is better, safer or more effective. A label that can be checked is not the same as a label that is true, and neither is the same as a product that works for any particular purpose. The next two sections explain those limits.

Why a printed percentage is still a claim

NCCIH notes that dietary supplements are not approved by the FDA before they are sold, and that manufacturers and distributors are responsible for evaluating the safety and labeling of their products before marketing. In practice, a standardization on a label is the company’s statement.

Published laboratory work shows why that matters for ginkgo in particular:

A 2016 study in the Journal of Herbal Medicine (Booker and colleagues) analyzed 35 ginkgo products and found that 33 had elevated levels of rutin and/or quercetin, or low levels of ginkgo’s own compounds, compared with reference samples. The authors suspected that adding cheaper rutin after extraction can let a sub-standard product look satisfactory on a flavonoid measure. A later conference abstract by the same group reported that only two of the 35 products showed the fingerprint described in the European and US pharmacopoeia monographs for ginkgo extract.
The 2019 Journal of Ethnopharmacology study reported that 48 of 59 ginkgo dietary supplements analyzed contained one or more adulterants.

Read those results with their limits in mind. They describe specific groups of products from specific markets, tested years ago. They do not tell you what is in any bottle you are holding today, and they do not mean every ginkgo product has a problem. What they do show is that a standardization printed on a label and a standardization measured in a laboratory can be two different things, which is why this guide does not treat a stated percentage as proof.

Where a label question ends

Reading labels can help you with a narrow set of questions: whether a product states an extract or only a leaf weight, whether it states a standardization, and whether the numbers on the panel can be multiplied out. It cannot answer these:

Whether ginkgo is worth taking. NCCIH states that there is no conclusive evidence ginkgo is helpful for any health condition. In the Ginkgo Evaluation of Memory (GEM) study, more than 3,000 people age 75 or older took ginkgo or a placebo for a median of 6 years, and dementia rates did not differ between the groups. NCCIH says ginkgo extract may have a modest benefit for dementia symptoms at relatively high doses, but that the evidence is inconsistent.
Whether it is right for you. NCCIH describes ginkgo leaf extract as likely to be safe for most adults in moderate amounts, with dizziness, stomach symptoms and headache as the most common side effects, and says it may be unsafe in pregnancy. Whether it suits your health history is a question for someone who knows that history. Our guide to ginkgo and dizziness covers one common side effect and how to organize what you bring to that conversation.
Whether it fits with your medicines. See the next section.

If you take a blood thinner or any other medicine

NCCIH says ginkgo may increase the risk of bleeding in people who take anticoagulant drugs such as warfarin, and that it may interact with other drugs too. MedlinePlus says blood thinners can interact with certain foods, medicines, vitamins and alcohol, and that your health care provider should know all of the medicines and supplements you use. Among the signs of serious bleeding MedlinePlus lists are a serious fall or bump on the head, bleeding from the nose or gums that does not stop quickly, and red or black bowel movements. Call your provider if you notice any of them.

For this situation, the percentage on the label is not the deciding factor. Neither source gives an amount of ginkgo that is considered safe alongside a blood thinner, so the decision belongs with your pharmacist or prescriber before you start, not after.

Your next step

Read the Supplement Facts panel and the “other ingredients” line, not only the front of the bottle. Note whether it says leaf, leaf extract, or both.
Look for a stated standardization and the weight it applies to. If you can’t find both, you can’t calculate an amount, and it is reasonable to ask the company what the extract contains.
Ask yourself which question you are really trying to answer. If it is “will this help,” the label cannot tell you. NCCIH’s summary of the evidence is the better place to start.
If you take any prescription medicine, especially a blood thinner, bring the exact label to a pharmacist or your prescriber before starting ginkgo, and ask them about it directly.
For general help reading panels and spotting vague claims, see our supplement label checklist.

Evidence limits

The NCCIH ginkgo page used here was last updated in February 2025, and the MedlinePlus blood thinners page was last updated June 27, 2024. Guidance can change.
The EGb 761 composition figures come from a 2003 summary and a 2013 review. They describe a reference extract used in research, not any particular bottle you can buy, and the two sources do not give exactly the same numbers.
The adulteration studies tested specific groups of products in 2016 and 2019. They cannot be applied to a particular bottle, brand or country, and they do not measure whether any product helps or harms anyone.
The three bottles in the scenario are invented. The arithmetic is real, but no real label was used and nothing about the example predicts an outcome.
Nothing here diagnoses a condition or recommends a product, dose or schedule. No source reviewed gives an amount of ginkgo that is safe with a specific medicine.

Sources checked October 8, 2026

National Center for Complementary and Integrative Health (NCCIH). Ginkgo: Usefulness and Safety. Last updated February 2025. nccih.nih.gov/health/ginkgo
National Library of Medicine, MedlinePlus. Blood Thinners. Last updated June 27, 2024. medlineplus.gov/bloodthinners.html
EGb 761: ginkgo biloba extract, Ginkor. Drugs R D. 2003;4(3):188-193. doi:10.2165/00126839-200304030-00009. PubMed 12757407.
Serrano-García N, Pedraza-Chaverri J, Mares-Sámano JJ, et al. Antiapoptotic Effects of EGb 761. 2013. doi:10.1155/2013/495703.
Booker A, Frommenwiler D, Reich E, Horsfield S, Heinrich M. Adulteration and Poor Quality of Ginkgo biloba Supplements. Journal of Herbal Medicine. 2016;6(2).
Frommenwiler D, Booker A, Vila R, Heinrich M, Reich E. Comprehensive HPTLC fingerprinting as a tool for a simplified analysis of purity of ginkgo products. Journal of Ethnopharmacology. 2019;243:112084, including supplementary product table.
Frommenwiler D, Booker A, Heinrich M, Reich E, Cañigueral S. Quality assessment of Ginkgo biloba supplements based on a single HPTLC method. Planta Medica International Open. 2017;4(S1). doi:10.1055/s-0037-1608584.

By DrBaba.com Health Research Team

This article is for general information purposes only and does not constitute medical advice. Consult your doctor or qualified healthcare provider before making changes to your health routine.