Several unintended consequences from just a single dose of testosterone, administered by a gel, have been documented in men by researchers representing three different U.S. universities.
In the first experiment, a group of 243 men received either a placebo in a gel or a dose of testosterone in a gel, and then took a cognition test to measure their decision-making judgment, based on their capacity to override incorrect intuitive assessments.
For example, one question asked was to assess how much a ball costs if the ball and a bat cost $1.10 total, with the bat costing $1 more than the ball. Men administered the dose of testosterone more readily answered—incorrectly-- that the ball costs ten cents. The correct answer was the ball costs five cents and the bat $1.05.
Why did most of the testosterone dose men get the answer wrong within a few hours after being administered it? The research team speculated that the testosterone increased confidence that their snap judgments (gut instincts) were correct, undermining their ability to assess and make rational decisions.
A second potentially negative effect was observed in a group of several hundred men, aged 18 to 55 years, who were given either a placebo treatment or a dose of testosterone and asked to choose from among several products, all similar in quality, but one being more of a luxury brand than the other.
The testosterone dose group became more prone to choosing the more expensive luxury brands, apparently because the testosterone increased their desire to make an impression for the purpose of status.
This phenomenon has been seen in some men, after they begin testosterone replacement therapy, when they go on buying binges, particularly in acquiring flashy sports cars to impress women.
“Single dose testosterone administration impairs cognitive reflection in men.” Nave G. Et al. Psychological Science. October 2017.
“Single-dose testosterone administration increases men’s preference for status goods.” Nave G. Et al. Nature Communications. 2018.