Testosterone and Healthy Brain Function
Richard Gaines, M.D., FAARM, ABAARM
The relationship between testosterone and increased physical strength has been long known. But what about when it comes to building mental muscle?
As men age it is no secret that memory and other cognitive issues develop, often mild, sometimes debilitating. Can low testosterone levels also play a role in age-related cognitive difficulties?
Testosterone and Cognitive Health
Scientists have speculated that testosterone does indeed play a role in healthy brain function in men. It does not seem to be mere coincidence that cognitive function and testosterone levels both decline with age.
Medical researchers have observed that men suffering from conditions other than aging that result in low testosterone levels, also experience cognitive dysfunction. A 2006 study published in the European Journal of Endocrinology indicated,
“Chemical castration studies in men with prostate cancer suggest that low serum testosterone may be associated with cognitive dysfunction. Low testosterone levels have also been observed in patients with Alzheimer’s disease, and mild cognitive impairment.”
A report two years later in the Harvard Men’s Health Watch also surmised there was a link between low-testosterone and age related memory loss. That study went on to conclude that supplemental testosterone treatments showed promise in being used to prevent, or even reverse age-related cognitive difficulties, but concluded more research is required.
Picking up where these earlier studies left off, researchers led by Dr. Justin Carré, tried more recently to determine a definitive link between testosterone and normal, healthy brain function.
The researchers knew that testosterone is related to the “fight or flight” response in men, and triggers “aggressive” behavior in response to a threat.
Dr. Carré and his team decided to focus their research on this known effect of testosterone on the brain, and discover its mechanism of action on brain circuitry.
Interestingly enough, earlier studies that attempted to determine these pathways, only tested supplemental testosterone’s effect on women.
The researchers used 16 healthy young males in the study. After making sure they were all at the same low-T base-level through deliberate suppression, the subjects received either testosterone or placebo in two days of testing. Those that received the actual testosterone, were given only enough to return them to a “normal” level, while those receiving the placebo, remained below the normal range. Subjects were then shown faces of angry, or aggressive men, while being subjected to brain imaging.
Upon analysis of the data, Dr. Carré was able to conclude,
“We were able to show for the first time that increasing levels of testosterone within the normal physiological range can have a profound effect on brain circuits that are involved in threat-processing and human aggression…”
Through brain imaging, the researchers were able to gain a better understanding of which areas of the brain testosterone effects, and see how it “turns-on” the fight or flight behavior in males.
This study provided the first definitive indication that increased testosterone levels boost the “normal” brain into a state of hyper-alertness and sharp focus in response to a perceived threat. This has some interesting implications for supplemental testosterone therapies.
While more research is needed, it stands to reason therefore, that testosterone replacement therapy for aging males, or other males suffering from low-T, that are experiencing cognitive difficulties, would benefit from the same “brain boost.”
A wealth of anecdotal evidence and testimony from men undergoing testosterone replacement treatments seems to indicate that this is the case.