Gingko Clinical Evidence

Nutrition Reviews. 
Gorby HE, Brownawell AM, and Falk MC. Do specific dietary constituents and supplements affect mental energy? Review of the evidence. 2010 Dec;68(12):697-718. 

Topic: 
How do four dietary supplements (including Gingko biloba and Panax ginseng) affect mental energy (defined as mood, motivation and cognition)?

Background:

The nut of the Gingko biloba tree has been used in traditional Chinese medicine as a treatment for respiratory problems. However, recent research indicates that the leaves of the plant treat cognitive dysfunction and boost mental energy. Panax ginseng is also an herb used in traditional Asian medicine, specifically as a stimulant.

Dosage:

Varied by study

Results:

The authors found that:

  • In one study, 240 mg daily of Ginkgo biloba improved some aspects of mood, namely alertness, calmness and contentedness.

  • In another study, 180 mg daily of Ginkgo biloba consistently increased speed of processing in young adults and older adults compared to placebo.

  • The effect of ginkgo appears to be immediate: A third study found that after 2.5 and 6 hours, both 240 mg and 360 mg dosages of ginkgo biloba improved speed of attention.

  • There was no consistent evidence that Panax ginseng improved mood or cognition. However, some studies do report improvements in the area of cognition.

Conclusion:

“The strongest evidence suggests effects of Gingko biloba on certain aspects of mood and attention in healthy subjects.” 

Gingko Mechanism of Action

Gingko improves levels of the neurotransmitters norepinephrine and dopamine, which increase nerve transmissions and brain activity related to attention, focus, and mood. It also increases or helps to maintain normal levels of ATP — a coenzyme involved in the production of energy at the cellular level — which may help alleviate mental fatigue. Finally, gingko increases blood flow and oxygenation to the brain.