Here’s a strange one: A study on testosterone published Oct. 10 in the online journal PLOS ONE concludes that testosterone administration can increase honesty in men. The article on the study, entitled “Testosterone Administration Reduces Lying In Men,” was authored by Dr. Matthias Wibral and associates from University of Bonn in Germany.

Testosterone, the most abundant male sex hormone, is associated with sex drive, skin health, lean muscle mass and aggression. Higher testosterone levels are associated with interpersonal and social dominance, status-seeking, physical dynamism – and in extreme cases, greater violence.

In the German study, the various researchers designed a simple test for honesty. They told participants to roll a six-sided dice in private and to report the result on a computer. The study participants were told ahead of time that the higher the number they rolled, the more money they would be given. A ‘1’ would yield them one euro, whereas a ‘5’ would yield them five euros. In every case, the study subject could make more money without fear of being caught, simply by claiming to have rolled a higher number.

In the two day study, 91 men were enrolled in the double-blind, placebo-controlled experiment, which was conducted at the Institute for Empirical Research in Economics at the University of Bonn. On the first day, one group received a transdermal testosterone gel, while the other group received a placebo gel. The testosterone was allowed to be absorbed for approximately 21 hours before the second part of the study commenced.

On the second day of the study, participants returned to the BonEcon lab test site, where they were invited to roll dice in privacy, report their numbers and collect their money. At no time were the study designers able to see the numbers rolled. The entire event was conducted in secure cubicles. After the rolling of dice, participants were given a basic personality test and had their blood sampled for testosterone levels. They were each paid the amount they clamed for rolling dice. Additionally, every participant was paid a flat 40 euros for their time.

Half of the men in the study showed high testosterone levels, while the other half had more normal levels. The study scientists, who did not know who had or had not received testosterone gel, correlated winnings and levels of the hormone in the study subjects. Their sampling showed that the men with the higher testosterone levels had claimed lower winnings overall. Follow-up showed that those men had received the real hormone gel. Conversely, the men who received the placebo gel claimed more high numbers rolled.

The cleverly designed study demonstrated that at least in this instance, administration of testosterone gel resulted in more honest reporting of dice rolling results, and lower earnings. In effect, the testosterone made men more honest.

Truth-telling is widely considered essential to a healthy and functional society. Yet people lie all the time, creating personal, business and social disturbances. Lying can result in devastating losses of relationship, prestige, money and social status. Any condition, agent or treatment that might promote greater honesty is of interest to social scientists. In the study performed in Bonn, researchers concluded that at least in this case, testosterone proves to be somewhat of a truth serum. Honestly.