Which clinical studies have measured blood pressure changes after taking Ginkgo biloba supplements?
Executive summary
Randomized, large-scale clinical evidence does not support a clinically meaningful blood‑pressure lowering effect of Ginkgo biloba in older adults: the Ginkgo Evaluation of Memory (GEM) randomized trial (3,069 participants) found no difference in systolic or diastolic blood pressure or incident hypertension between 240 mg/day ginkgo and placebo over a median 6.1 years [1][2]. Smaller, heterogeneous clinical trials and pilot studies — some showing modest diastolic or systolic reductions and others showing no effect — create a mixed picture and limit firm conclusions [3][4][5].
1. The big randomized trial: GEM’s negative finding and its scope
The largest clinical study measuring blood pressure after Ginkgo biloba was the Ginkgo Evaluation of Memory (GEM) trial, a double‑blind randomized controlled trial of EGb 761 at 240 mg/day in 3,069 older adults that specifically analyzed blood pressure change and incident hypertension and reported similar changes in blood pressure and pulse pressure between ginkgo and placebo over a median 6.1 years, leading the authors to conclude Ginkgo did not reduce BP or hypertension incidence in this elderly population [1][2].
2. Small clinical pilots that reported modest reductions — context and caveats
A 2‑month clinical pilot in 11 metabolic‑syndrome patients reported reductions in diastolic blood pressure of roughly 5 mmHg after EGb 761 (2×120 mg/day) and suggested links to oxidative‑stress biomarkers, but the sample size and pilot design make this preliminary and hypothesis‑generating rather than definitive [4]. Other small, often non‑blinded or add‑on studies, including a 43‑patient ambulatory BP observation where ginkgo was given alongside antihypertensive therapy, reported BP changes but cannot isolate the effect of ginkgo from concurrent drugs or regression to the mean [6].
3. Systematic reviews and meta‑analyses: inconsistent signals and methodological limits
A systematic review of randomized trials for essential hypertension found that six trials suggested a potential adjunctive benefit of Ginkgo biloba extracts when added to conventional antihypertensives, but the overall evidence was heterogeneous, methodologically weak, and did not produce a consistent, statistically significant reduction in systolic and diastolic BP across studies, prompting authors to call for more rigorous trials [3]. Reviews and meta‑analyses therefore reflect inconsistent signals: some small trials report benefits whereas higher‑quality, larger trials do not [3][7].
4. Mechanistic and preclinical data: plausible vasodilatory effects not yet translated
Preclinical studies in spontaneously hypertensive rats and ex vivo vascular work show that Ginkgo extracts can promote vasodilation via nitric‑oxide pathways and improve endothelial responsiveness, producing blood‑pressure reductions in animal models, which provides biological plausibility for antihypertensive effects but does not guarantee the same magnitude of effect in humans [8][9]. Translational human studies are mixed: some short human trials showed transient or modest BP decreases while others, including 7‑day and longer dosing in healthy volunteers, reported no change [5][10].
5. Where the evidence stands, practical implications, and hidden agendas
Taken together, the clinical literature contains a few small positive trials, several negative or null studies including the large GEM trial, and systematic reviews that flag publication bias, heterogeneity of preparations, and poor trial quality as major limitations — factors that can inflate positive impressions in smaller studies and in industry or regionally produced preparations [3][7][11]. Some Chinese clinical programs and product‑specific studies report benefits when ginkgo‑based patent medicines are combined with conventional antihypertensives, but these reports often derive from trials with unclear blinding, variable formulations, and limited reporting of adverse events, creating potential for commercial or regulatory agendas to shape conclusions [11][12].
6. Bottom line and next steps for researchers and clinicians
Definitive evidence of clinically meaningful blood‑pressure lowering by Ginkgo biloba in humans is lacking: large randomized data in elderly adults were negative (GEM), small pilots show possible modest effects that require replication, and systematic reviews call for larger, better‑controlled RCTs with standardized extracts and attention to concomitant medications and safety reporting [1][2][3][5]. Claims of routine antihypertensive use of Ginkgo remain premature given current trial heterogeneity and methodological concerns [3][7].