A number of studies in recent times have cast doubt over the efficacy of gingko biloba for most of its touted benefits, and today another study published this week in JAMA concludes that gingko biloba supplements have no effect on the incidence or severity of dementia or Alzheimer’s disease.

More than 3,000 participants aged more than 75 years and with normal cognition or mild cognitive impairment were given gingko biloba 120 mg twice daily or a placebo, and followed-up at 6-monthly intervals for a median period of 6.1 years.

The incidence of dementia or Alzheimer’s disease was slightly but insignificantly greater in the supplementation group, indicating that gingko biloba has no effect on the incidence of dementia.

A 2002 study in JAMA titled “Ginkgo for memory enhancement: a randomized controlled trial” also reported the lack of any significant effect on memory enhancement in a 60+ year olds.

The hypothesis, or perhaps ‘traditional knowledge’ behind this idea that gingko improves your mind I believe comes from its purported ability to improve peripheral circulation, particularly in the capillaries. The extension of this is that it would improve cerebral circulation too, allowing more oxygen and energy to the brain. The results seem to suggest otherwise, however.

In my experience, I felt that the first 2 or 3 times I took gingko biloba supplements, I felt an effect that could be interpreted as an increase in alertness, but with repeated dosing I felt nothing. Perhaps one quickly develops a tolerance to its effects, such that there is no point using it chronically.

Either way, it’s probably not worth wasting your money on.