Testosterone and cognitive function: current clinical evidence of a relationship

Area of Science:

• Gerontology
• Neuroendocrinology
• Cognitive Neuroscience

Background:

• Testosterone levels naturally decline with age in men, coinciding with potential decreases in cognitive function.
• Observational studies suggest a link between low testosterone and cognitive dysfunction, including in Alzheimer's disease (AD) and mild cognitive impairment (MCI).
• The precise relationship between testosterone and cognitive function in aging men requires further elucidation.

Purpose of the Study:

• To systematically review the existing clinical evidence on the association between serum testosterone levels and cognitive function in older men.
• To evaluate the impact of testosterone substitution therapy on cognitive performance in aging men, including those with hypogonadism, AD, or MCI.

Main Methods:

• A systematic literature search was performed using PubMed and EMBASE databases.
• Included studies and reviews focused on cognitive function and endogenous testosterone levels or testosterone substitution effects in older men.

Main Results:

• Low endogenous testosterone levels in healthy older men correlate with poorer performance on specific cognitive tests.
• Randomized, placebo-controlled trials show mixed but generally moderate positive effects of testosterone substitution on selective cognitive domains, such as spatial ability.
• Similar cognitive benefits from testosterone substitution have been observed in patients with existing AD or MCI.

Conclusions:

• Reduced cognitive ability in older men may be linked to low endogenous testosterone levels.
• Testosterone substitution therapy shows potential for improving certain cognitive aspects in older men, particularly those with cognitive impairment and low testosterone.
• Further large-scale, long-term studies are necessary to confirm the efficacy of testosterone substitution for cognitive enhancement in aging men.