In conjunction with the known associations of lower testosterone concentrations with risk of dementia (as discussed earlier), it has been postulated that testosterone may play some role in the interaction between excess adiposity, diabetes and dementia . We hypothesise that epidemiological studies reflect an extended period of exposure to differences in circulating testosterone concentrations, resulting in subtle but cumulative effects on cognition, in a manner not replicated in clinical trials of relatively shorter duration. Some smaller clinical trials, often using intramuscular injections of testosterone, suggest a benefit of testosterone intervention on specific measures of cognitive function, but other trials have shown no benefit 84–94, 96, 103–107. Another using transdermal testosterone over 6 months in 16 men with Alzheimer’s disease, reported a trend to improvement in visuospatial function, but no difference in verbal memory . One trial in 32 men with either MCI or Alzheimer’s disease, of weekly intramuscular testosterone treatment over 1.5 months, reported improvement in spatial ability and verbal memory . In the TEAMM trial, 140 men in each group were included in the final analysis, finding no benefit of testosterone treatment for visuospatial ability, verbal fluency, verbal memory, manual dexterity, attention or executive function. In that study testosterone treatment reduced fat mass and increased lean mass, but there were no differences between groups for visuospatial performance, perceptual speed, attention, or verbal memory.
In a study of 23,651 men with prostate cancer median age 73 years, 1,525 were diagnosed with incident dementia during median follow-up of 3.5 years. However, functional MRI studies showed subtle differences in medial prefrontal cortical activation, and connectivity between the medial prefrontal cortex and other regions involved with cognitive control between groups . Two small observational studies reported increases in β-amyloid concentrations in men following androgen deprivation therapy (ADT) for treatment of prostate cancer 66, 67. UK Biobank also utilised registry data to ascertain diagnoses of dementia and dementia due to Alzheimer disease, using an algorithm validated against clinical expert adjudication of full-text medical records 64, 65. By contrast, men with lower SHBG concentrations had a lower incidence of dementia, and of dementia due to Alzheimer disease . In comparison the risk of dementia increased by 11% per 1 standard deviation lower baseline total testosterone concentration . The possible implication may be that testosterone might have beneficial effects on the brain through non-Alzheimer pathology-related mechanisms.
Seven large studies showed that low plasma testosterone levels substantially increase the risk of Alzheimer's disease by 48% in older men32. Mechanistic studies indicate that testosterone may have protective effects within the brain, slowing the development of the multiple pathologies found in men with dementia due to Alzheimer disease. Large, well-powered epidemiological studies adjusting for potential confounders show middle-aged and older men with lower testosterone concentrations have a higher risk of being diagnosed with dementia 13, 14.
The Testosterone Trials (T Trials) recruited 788 men aged ≥ 65 years, with baseline total testosterone 109. Another trial in 11 men with mild cognitive impairment (MCI) of intramuscular testosterone given every 3 weeks, over 3 months, found no difference in cognitive test results . Several earlier and relatively small trials in men with mild cognitive impairment or probable Alzheimer disease, reported inconsistent results 103–106. The above studies were conducted in men from the general population, who were not selected for the presence of cognitive impairment at baseline 84–98. Participants in LITROS were older men (≥ 65 years) who were obese (BMI ≥ 30 kg/m2), had baseline total testosterone concentrations 98]. Of note, a recent secondary analysis of the Lifestyle Intervention and Testosterone Replacement in Obese Seniors (LITROS) trial, examined the effect of transdermal testosterone compared to placebo, on a background of an intensive weight management and exercise program . Earlier studies included 15 to 88 participants, used transdermal, oral or intramuscular formulations of testosterone, and were conducted mainly in older men from the general population 84–94, 96.|The Testosterone Trials (TTrials) Cognitive Function substudy stands as one of the most complete studies. New clinical trials show mixed results about testosterone's brain benefits. The American College of Physicians points out limited proof that testosterone helps anything beyond sexual function18.|The T Trials sub-studies showed that testosterone treatment improved anaemia, and increased volumetric bone mineral density 130, 131. T4DM is the largest testosterone randomised controlled trial completed to date, with an unequivocal result showing a beneficial effect of testosterone treatment, in the setting of a background lifestyle intervention, to prevent or revert type 2 diabetes in men at high risk. Therefore, lifestyle measures which prevent or help manage type 2 diabetes may overlap to some degree with lifestyle measures to reduce future risk of dementia 19, 20.|Studies show that men with lower testosterone levels have an increased risk of developing dementia and Alzheimer's disease. On top of that, regular exercise works wonders - resistance training is the quickest way to keep testosterone levels healthy and support brain function. Research shows mixed results about testosterone therapy for cognitive improvement, but healthy hormone levels play one of the most important roles in how our brain works. Natural approaches can help aging men keep their testosterone levels healthy while supporting brain function aging men.|The FDA requires manufacturers to update their labels because safety and effectiveness haven't been proven for age-related low testosterone28. Let's tackle some common questions about testosterone and memory with research-backed answers. Note that memory problems can stem from many sources beyond hormones. They measure testosterone in your blood, looking at both total testosterone and sex hormone binding globulin (SHBG)24. They check your memory through physical exams, blood tests, brain scans, and specific memory evaluations9. A neurologist looks at how your brain works and gives you a complete cognitive assessment to understand why it happens21.|They can make daily life harder and might point to conditions that need treatment. These symptoms go beyond just forgetting things occasionally. Other trials found slight improvements in focus, planning skills, and word memory20. Testosterone therapy brings several risks that need careful assessment. Tests typically reveal levels below 300 ng/dL in multiple morning measurements16. TRT works best for men who have documented testosterone deficiency syndrome. While all exercise helps somewhat, resistance training and HIIT work best for quick testosterone boosts4.|Can overtraining negate the testosterone-boosting effects of exercise? Aim for 7-9 hours of quality sleep per night to support optimal hormonal function. Is there an ideal age to start exercising for testosterone benefits? If you suspect you have low testosterone, consult with a healthcare professional. Symptoms of low testosterone can include fatigue, decreased libido, erectile dysfunction, loss of muscle mass, increased body fat, and mood changes. Focus on a balanced diet rich in protein, healthy fats, and micronutrients to support natural testosterone production. Can vary based on age, genetics, and pre-existing health conditions.|All of this reduces the active (free) form of testosterone in the body. The testes produces less testosterone, there are fewer signals from the pituitary telling the testes to make testosterone. Among women, perhaps the most common cause of a high testosterone level is polycystic ovary syndrome (PCOS). Having too much naturally-occurring testosterone is not a common problem among men. But having high cholesterol doesn't mean your testosterone will be high. The proper balance between testosterone (along with other androgens) and estrogen is important for the ovaries to work normally. It's one of several androgens (male sex hormones) in females.|Medicare enrollees (usually at age 65) should get basic cognitive screening during yearly wellness visits47. You should think about cognitive screening if memory lapses affect your daily activities or safety46. This differs from verbal memory decline, which usually follows a straight line45. Studies point to a non-linear relationship between executive function and age, with notable changes starting in the mid-50s45. Everyone forgets things now and then, but brain fog tied to hormonal changes is different from normal aging. This proves testosterone helps keep the brain working well.}
The decision needs a careful look at benefits, risks, and new scientific evidence before starting treatment. Research shows that treadmill exercise helped fix spatial memory problems in rats with low androgens by increasing testosterone and estradiol in the hippocampus15. Your brain specifically uses DHA in its cell membranes, which shows how important it is for nervous system function7. B vitamins are vital for brain health and how well you think. Your hormone levels work best with a nutritious diet that balances protein, fat, and carbohydrates4.
This happens because Leydig cells die off and the brain releases less hormone-triggering chemicals37. These actions let testosterone control everything from your mood to memory. About 20% of men at age 60 have testosterone deficiency, and this number jumps to 50% by age 8032.
Doctors also watch out for high red blood cell counts, which could increase the risk of clotting. As a result, there is some controversy about which men should be treated with supplemental testosterone. Men taking testosterone replacement must be carefully monitored for prostate cancer. There are times when low testosterone is not such a bad thing.