Individuals masked to treatment group assignment assessed outcomes. To maintain participant and treating-clinician masking, the dosage of placebo gel was also adjusted simultaneously. These investigators recruited adult men, 65 years or older, with a mean of two morning serum testosterone concentrations of less than 275 ng per dL (9.5 nmol per L). This study was supported by young scientist research grants from the Korean Society for Sexual Medicine and Andrology (2011). Brain fog is not a medical term, but it describes a collection of symptoms that affect the way you think. Low testosterone, also known as hypogonadism, can occur due to several reasons. These symptoms can make it difficult to focus on tasks, remember important information, and think clearly. In the Baltimore Longitudinal Study of Aging, men with a higher ratio of testosterone to SHBG at baseline performed better on tests of cognitive function, and were less likely to develop Alzheimer’s disease, during extended follow-up (10 and 19 years respectively) 57, 58. However, a study of middle-aged and older rats given a high-fat diet reported relatively subtle effects of testosterone treatment over 12 weeks to prevent diet-induced increases in microglial and astroglial reactivity, with equivocal effects on behavioural outcomes . Deterioration in cognitive function can affect multiple domains of memory, thinking, orientation, comprehension, calculation, learning capacity, language, and judgement. Age is a strong but irreversible risk factor for cognitive decline and incidence of dementia, albeit these are not inevitable consequences of ageing . Similarly, in T4DM, testosterone treatment improved sexual function, and also improved volumetric bone mineral density predominantly via effects on cortical bone 127, 132. Therefore, testosterone treatment in conjunction with lifestyle intervention, addresses two key factors predisposing to dementia, namely obesity and diabetes, but its effect on dementia risk remains unproven. Whether such lifestyle interventions combined with testosterone treatment might protect against both type 2 diabetes and cognitive decline, remains unclear. 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. No significant group differences were found at the end of the study; however, mildly demented patients who received testosterone experienced less decline in visuospatial abilities. In a six-month placebo-controlled study, male patients with Alzheimer’s disease (AD) were randomized to DHEA 50 mg twice daily vs. placebo. Blood levels of DHEA gradually decline with aging until it reaches its lowest level in the seventh decade, resulting in a variety of physiological, mental, and emotional problems such as reduced stamina, memory problems, and decline in sex drive. DHEA plays many important roles in the body and brain including modulation of cognition, memory, appetite, immune function, cardiovascular function, and sexual behavior. Future studies should use a standardized method of T delivery, serum T assessments, and the cognitive tests and subtests used to assess cognition. Our systematic review of the current state of knowledge about cognition and T in older men and the potential role of T supplementation in age-related cognitive disorders has led us to make several recommendations for the directions of research. In summary, the overall quality of controlled studies published as of February 2016 and included in our review is not adequate to provide recommendations and clinical guidelines for T supplementation to preserve or improve cognitive performance.
