Ginkgo Biloba

Proposed mechanism

Ginkgolides block platelet-activating factor (PAF) receptors, a signal that drives platelet clumping and inflammation. That receptor activity is well documented in laboratory and animal studies, but it has not been shown to thin the blood in people: a 2011 meta-analysis of 18 randomized trials (1,985 adults) found no effect of standardized Ginkgo extract on platelet aggregation or standard clotting markers versus placebo. Bleeding case reports and a documented interaction with warfarin do exist, and are covered under safety and interactions. Flavonoids scavenge reactive oxygen species in neural tissue. Ginkgo is widely described as increasing cerebral blood flow, but human results are inconsistent: a small uncontrolled MRI study in nine older men found a modest increase after four weeks, while a pooled analysis of 15 randomized trials found no clear effect on cerebral artery flow velocity. The most consistent circulatory finding in human trials is reduced blood viscosity. Increased flow to brain regions affected by traumatic brain injury has not been shown in people, and is not among the mechanisms reported in the TBI animal literature, which instead shows reduced oxidative stress and inflammation; no controlled trial has tested Ginkgo on its own in people with TBI, and a 2026 systematic review concluded that clinical data remain insufficient to justify routine therapeutic use.

Mechanisms describe how researchers think a compound may act, often from laboratory work — a proposed mechanism is not proof of a clinical effect in people.