The Slovaks had seventy test persons learn words off by heart, and then asked them to write these words down. At the same time the test persons had to squeeze hand grips. Combining the two tests produced psychological and physical stress. Stress usually induces an increase in the production of the stress hormone cortisol, but this did not happen in the men that took 120 mg of Ginkgo 30 minutes before the test.
Ginkgo slows down the production of cortisol in two ways. The leaves contain Ginkgolide B, a heavily oxidised terpene, that slows down the production of cortisol from cholesterol in the cells of the adrenal glands. [Cell Mol Biol (Noisy-le-grand). 2002 Sep;48(6):633-9.]
The second way in which Ginkgo decreases cortisol levels only becomes evident when Ginkgo is used over a long period of time. According to animal studies, the same Ginkgolide B slows down the release of corticotropin releasing hormone (CRH) by the hypothalamus. [Life Sci. 1998;62(25):2329-40.] CRH makes the adrenal gland produce cortisol.
Decreasing the cortisol level is interesting for strength trainers as well as those seeking longevity. Cortisol is a catabolic hormone: the fewer catabolic hormones circulate in your body after training, the more muscle mass and strength you build up.
For longevity seekers it also is worthwhile decreasing the level of cortisol, as cortisol is not only a stress hormone but also an aging hormone. Elderly people produce more cortisol than young people, and an elevated cortisol level prevents brain cells from making new connections. Survival chances at a higher age improve if brain cells make more new connections.
J Physiol Pharmacol. 2002 Sep;53(3):337-48.