Effect of Ginkgo biloba Extract on Plasma Steroid Concentrations in Healthy Volunteers: A Pilot Study

Study Objective. To determine if a standardized ginkgo supplement significantly alters concentrations of circulating androgenic steroids in humans.

Design. Open-label, fixed–treatment order, crossover study.

Setting. University general clinical research center.

Subjects. Eleven healthy volunteers (six men, five women).

Intervention. Volunteers received ginkgo biloba 240 mg/day for 14 days.

Measurements and Main Results. Plasma concentrations of cortisol, 11-deoxycortisol, 17α-hydroxyprogesterone, testosterone, dihydrotestosterone, dehydroepiandrosterone sulfate, sex hormone–binding globulin, androstenedione, and free testosterone, as well as free androgen index and combined concentrations of androsterone sulfate and epiandrosterone sulfate, were analyzed in all subjects before and after their 14-day course of ginkgo biloba. Ginkgo biloba did not significantly alter endogenous steroid levels compared with baseline values (p<0.05).

Conclusion. A 14-day oral administration of a widely used, standardized ginkgo extract at a generally advocated dosage of 240 mg/day did not significantly alter concentrations of major circulating steroids in men and women.