While it’s true that testosterone’s primary functions are sexual desire and sexual function, researchers are finding that testosterone affects much more. An additional potential role for testosterone is that of cognition or helping you think.

While testosterone isn’t the only hormone involved in cognition, research suggests the hormone may play a part in brain health. Keep reading to find out more about the connections between testosterone, brain fog, and thinking.

Here’s a quick summary of what researchers currently know about testosterone and the brain.

Testosterone is a type of hormone called an androgen. Researchers have identified that within the brain, there are specific androgen receptors. Think of these receptors as light switches that only androgen hormones can activate.

Researchers also know that testosterone can cross the blood-brain barrier. This barrier is a protective mechanism in your brain designed to keep substances that could potentially damage it out, and allow other substances in (including some medications). The fact that testosterone can cross the blood-brain barrier means that it could cause some changes in thinking or brain functioning.

Researchers have also found testosterone has protective effects on the brain. Examples include:

  • delaying nerve cell death
  • improving nerve cell regrowth after damage
  • reducing the effects of nerve damage
  • having anti-inflammatory actions on the nerves

These are just some of the potentially protective benefits to the brain that researchers think testosterone may have, and we’re sure to learn more in the coming years as studies continue.

Language matters

In this article, we use “male and female” to refer to someone’s sex as determined by their chromosomes, and “men and women” when referring to their gender, unless quoting from sources using nonspecific language. The studies cited within the article frequently do not delineate between sex and gender and can be assumed to have entirely cisgender participants.

Sex is determined by chromosomes, and gender is a social construct that can vary between time periods and cultures. Both of these aspects are acknowledged to exist on a spectrum both historically and by modern scientific consensus.

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Cognitive decline tends to occur with aging. Testosterone levels also tend to decrease with aging as well. Some smaller studies also suggested that men with lower testosterone levels tend to have poorer cognitive function than men the same age with higher testosterone levels.

Sometimes, low testosterone levels cause symptoms such as difficulty maintaining an erection or low sex drive. People tend to connect these more with low testosterone, but it can also cause symptoms that don’t seem connected to testosterone at first. These nonspecific symptoms include:

  • affected memory
  • fatigue or low energy levels
  • reduced physical strength
  • Increased irritability
  • higher instances of depression

If you have these symptoms, and can’t identify another underlying cause (like staying up late at night or a poor diet), low testosterone levels could play a role.

Most of the studies that connect testosterone with improving mental function are on older men, often because they may be more impacted by changes in memory function. However, researchers have actually found higher testosterone levels reduce the abilities to perform thinking tasks in younger males. For this reason, researchers tend to think low testosterone could negatively impact thinking specifically in older age.

What happens if low testosterone goes untreated?

Low testosterone can cause symptoms that include low sex drive, reduced lean muscle mass, erectile dysfunction, and fatigue. Those with low testosterone many have difficulty focusing and lower energy levels, yet don’t know their symptoms are related to low testosterone.

Low testosterone can certainly affect your life, especially your sex life, which can be an important part of your overall health and well-being. However, low testosterone doesn’t tend to cause many significant life threatening conditions. An exception is that low testosterone can cause weakened bones, which increases your risk for osteoporosis.

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Studies haven’t been conclusive on the likely effects of testosterone on brain fog or thinking. However, most available studies point to the idea that testosterone supplementation doesn’t improve thinking. Here’s some examples:

  • One systematic review found that men who took androgen deprivation medications to treat prostate cancer (which would result in low testosterone) didn’t find a link between cognitive impairment and low testosterone.
  • In a study of 493 men with age-associated memory impairment and low testosterone who utilized testosterone, there were no improvements in memory or cognitive function.
  • A meta-analysis of 17 studies on testosterone replacement therapy and cognitive function did not find any differences in cognitive function between men who took testosterone replacement and those who didn’t.
  • Another systematic review of 23 independent randomized controlled trials (RCTs) did not find a statistically significant change in cognitive function from testosterone supplementation.

While larger randomized controlled studies are still needed, current evidence doesn’t support using testosterone therapy as a way to improve your mental abilities.

Does taking testosterone change the brain?

Taking testosterone doesn’t change the physical structure of the brain. There’s also no consensus to fully support that taking supplemental testosterone creates changes in thinking or memory.

However, there are smaller studies and individual case reports that suggest that testosterone supplementation may help improve cognition. You can ask your doctor about the potential individual benefits (and risks) of testosterone therapy.

How do you fix low testosterone?

Doctors can prescribe different forms of testosterone as a method to increase your testosterone if yours is below a healthy level. Examples include:

Testosterone supplementation has side effects. Gel testosterone can be especially troublesome for those with young children. Discuss these with your doctor to ensure you can safely take it.

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Low testosterone can affect your energy levels and thinking, which could contribute to brain fog. Unfortunately, researchers haven’t established that testosterone replacement therapy can alter these effects. Researchers will continue to pursue studies until they can definitively say that testosterone supplements don’t have an effect on thinking.

If you’re curious if you have low testosterone, talk with your doctor about testing and potential treatments.