What does the 24/6 specification of Ginkgo biloba leaf extract mean?
The 24/6 specification of Ginkgo Biloba Extract is a universally recognized standardized active ingredient ratio marker in the industry, which means the content of total flavonol glycosides ≥ 24% and the content of terpene lactones ≥ 6%. There are also low-proportion, high-proportion and crude extract specifications in the industry.
1. Origin of the 24/6 Standard
This standard was first derived from the standardized extract EGb761 in Germany. In the 1960s, German pharmaceutical companies extracted active ingredients from ginkgo leaves. To ensure consistent effects across different batches, they set a “formula ratio”: total flavonol glycosides no less than 24%, and terpene lactones no less than 6%.
Later, this ratio was included in the Chinese Pharmacopoeia, United States Pharmacopeia and European Pharmacopoeia, becoming a global model for plant drug quality control. Its core significance is that as long as the 24/6 standard is met, the proportion of active ingredients remains basically consistent, making clinical effects comparable.
2. About the 5ppm Limit of Ginkgolic Acid
Ginkgolic acid is a natural impurity in ginkgo leaves. It is irritating and sensitizing, which may cause rashes and gastrointestinal discomfort. Long-term high intake may also lead to cytotoxicity. Therefore, a key step in the extraction process is to remove ginkgolic acid as much as possible.
Both international pharmacopoeias and the Chinese Pharmacopoeia stipulate that the total ginkgolic acid in ginkgo leaf extracts shall not exceed 5ppm (ppm means parts per million; 5ppm means no more than 5 milligrams of ginkgolic acid per kilogram of extract).
China’s health food industry has a stricter group standard (T/CNHFA 001-2019), which requires the content to be ≤3ppm, stricter than the European and American standards.
3. Specific Meaning of the 24/6 Specification
- The “24” in the first part: It means that the proportion of total flavonol glycosides in the total mass of the extract is no less than 24%. These components are mainly responsible for anti-oxidation and protecting vascular endothelium.
- The “6” in the second part: It means that the proportion of terpene lactones (Ginkgolide A/B/C, etc.) in the total mass of the extract is no less than 6%. The core function of these components is to improve microcirculation and inhibit platelet activation.
Not a tablet specification: It refers to the component proportion of the extract powder, not the weight of each tablet.
Example: If each tablet contains 40mg of extract, it is converted to about 9.6mg of flavonol glycosides and 2.4mg of terpene lactones according to the 24/6 standard.
4. Other Common Specifications in the Industry
| Specification Type | Component Proportion | Common Uses | Features |
|---|---|---|---|
| 24/6 Standard Extract | Flavonol glycosides ≥24%, terpene lactones ≥6% | Pharmaceuticals, high-end health products | Most clinical evidence; strictest quality control |
| Low-proportion Extract | Flavonol glycosides 5%, 10%, etc. | Ordinary health products, herbal teas | Lower cost; limited clinical evidence |
| High-proportion Extract | Flavonol glycosides above 50% | Concentrated health products | High concentration; limited clinical data |
| Crude Extract / Leaf Powder | Ratios such as 4:1, 10:1, 20:1 | Food ingredients, cosmetics | No defined active proportion; significant batch variability |
5. Differences and Restrictions of Different Specifications
24/6 Standard Extract: Included in pharmacopoeias, with the most clinical studies, it is the gold standard at the pharmaceutical grade.
Low-proportion or Crude Extracts: Without a unified proportion of active ingredients, they vary greatly among manufacturers and cannot be equivalent to pharmaceutical effects.
High-proportion Extract: With high component concentration, it does not mean better effects, and may also increase the risk of adverse reactions.
24/6 specification is the mainstream benchmark for B-end procurement. The vast majority of Ginkgo Biloba Extract raw material quotations and production capacity supplies in the market are based on the 24/6 specification, which is the industry’s default “standard product”.
Usage Restrictions: Ginkgo leaf extract cannot replace antiplatelet drugs such as aspirin and clopidogrel. Pregnant women, lactating women, children and people with liver or kidney dysfunction must consult a doctor or pharmacist before use.
