Ginkgo science review
by Paul Bergner
Medical Herbalism 3(2):3
How effective is Ginkgo biloba extract in increasing peripheral circulation? The blood flow in nail-fold capillaries increased by 57% one hour after administration of a dose in a single-blind, placebo controlled, cross-over study. Blood pressure and heart rate were not affected.
Jung F, Mrowietz C, Kiesewetter H, Wenzel E. “Effect of Ginkgo biloba on fluidity of blood and peripheral microcirculation in volunteers.” Arzneimittelforschung 1990 May; 40(5):589-93
How long for a trial run for ginkgo? Sixty patients with cerebral insufficiency and depression were treated in a double-blind study for six weeks with a daily dose of 160 mg Ginkgo biloba extract or placebo. After two weeks the differences were marked for only a few of the symptoms measured; after four and six weeks in contrast, improvement was clear in eleven of the twelve symptoms. The largest number of improvements in the ginkgo group was observed between the second and fourth weeks of treatment. In this period, about two-thirds of the patients on Ginkgo biloba, and about one-fifth of the patients on placebo showed improvements.
Eckmann F. “Cerebral insufficiency—treatment with ginkgo-biloba extract. Time of onset of effect in a double-blind study with sixty inpatients” Fortschr Med 1990 Oct 10;108(29):557-60
Note: both these cases used a
concentrated standardized extract of ginkgo, and the results cannot be
expected to apply to other forms.