Ginkgolides are a group of diterpene lactones found in Ginkgo biloba leaves, and are considered among the active constituents responsible for the pharmacological effects of Ginkgo extracts. The use of Ginkgo biloba for improving cerebral circulation and cognitive function has roots in traditional medicine, but there is also scientific investigation supporting its effects. Several randomized controlled trials and meta-analyses have explored standardized Ginkgo biloba extracts (not isolated ginkgolides) for their potential to improve blood flow to the brain, cognitive function, and symptoms of vascular dementia or age-related cognitive decline. The proposed mechanism involves ginkgolides inhibiting platelet-activating factor (PAF), leading to reduced platelet aggregation, improved microcirculation, and vasodilation, which could enhance cerebral blood flow.

However, while some studies have shown modest improvements in cognitive performance and cerebral blood flow, the overall evidence remains mixed, with some large trials failing to find significant benefits. The quality of studies varies, and many use whole Ginkgo biloba extracts rather than isolated ginkgolides, making it difficult to attribute effects solely to ginkgolides. The European Medicines Agency and some clinical guidelines acknowledge possible benefits of Ginkgo for cognitive impairment and peripheral circulatory disorders, but typically note that evidence is inconclusive or the effect size is small. As such, there is scientific rationale and some clinical evidence, but it is not robust or unequivocal.