Effects of Testosterone on Higher Thinking, Impulse Control, and Executive Functioning
Based on the most recent and highest quality evidence, testosterone does not improve cognitive function, including higher thinking, impulse control, and executive functioning in men. 1
Evidence on Cognitive Effects of Testosterone
Cognitive Function in Clinical Trials
- The Cognitive Function Trial, part of the Testosterone Trials, enrolled 493 men with age-associated memory impairment and found no association between testosterone treatment and improved cognitive outcomes 1
- A study of 280 cognitively normal men reported that long-term testosterone treatment did not improve cognitive function across multiple domains, including:
- Verbal memory
- Visuospatial memory
- Language
- Executive function 1
Mechanisms of Testosterone's Neurological Effects
Testosterone may influence brain function through several pathways, though these don't translate to clinical cognitive benefits:
- Amyloid β metabolism: Testosterone plays a role in producing neprilysin, an enzyme that helps clear amyloid β (associated with Alzheimer's disease) 1
- Brain-derived neurotrophic factor (BDNF): Testosterone may influence BDNF concentrations, with testosterone reduction leading to reduced hippocampal BDNF in animal studies 1
- Antioxidant effects: Testosterone may be associated with transcription of antioxidant genes and increased superoxide dismutase, potentially counteracting oxidative stress 1, 2
- Conversion to estradiol: As a precursor to estradiol, reduced testosterone could decrease estradiol synthesis in the male brain 1
Sex-Specific Effects on Executive Function
Research suggests potential sex-specific effects of testosterone on brain structure and function:
- In boys (but not girls), testosterone levels are associated with prefrontal-hippocampal structural covariance 3
- Higher testosterone levels in boys are associated with poorer performance on specific executive function components:
- Action monitoring
- Cognitive flexibility (shifting between actions) 3
- This relationship appears to be mediated by prefrontal-hippocampal structural covariance 3
Inconsistent Findings Across Studies
The relationship between testosterone and cognitive function shows mixed results:
- Some studies suggest low endogenous testosterone may be associated with reduced cognitive ability in older men 4
- A single testosterone injection was found to block practice effects in verbal fluency tasks but had no effect on spatial or verbal memory 5
- In women, low testosterone levels were associated with poorer cognitive function, but only in APOE-ε4 carriers 6
Clinical Implications
Despite theoretical mechanisms by which testosterone might affect cognition, the highest quality clinical evidence does not support using testosterone to improve cognitive function:
- Nine studies examining cognitive outcomes showed variable results, with most being underpowered 1
- Studies in patients with Alzheimer's disease or mild cognitive impairment have been preliminary with small sample sizes 1
- The most robust evidence from the Testosterone Trials shows no benefit for cognitive function 1
Potential Risks of Testosterone Therapy
When considering testosterone therapy, be aware of potential risks:
- Cardiovascular events (though pooled risk did not differ significantly between testosterone and placebo groups) 1
- Erythrocytosis (increased red blood cell production), which can increase blood viscosity and potentially affect cerebrovascular circulation 2
- Headaches, particularly in elderly patients or those with pre-existing conditions that independently increase hematocrit 2
In conclusion, while testosterone plays various roles in brain function through multiple mechanisms, current high-quality evidence does not support its use for improving higher thinking, impulse control, or executive functioning.