Testosterone, commonly thought of as the male sex hormone, seems to promote honesty, a new study suggests.

Testosterone also is naturally found in women but at lower levels than in men, and is typically associated with macho attributes such as aggression and risky behavior. However, recent research indicates that the hormone also encourages social behavior.

In the new study, German researchers led by Dr. Matthias Wibral of the University of Bonn department of economics applied a testosterone gel to the skin of 46 men to boost their levels of the hormone and an inactive placebo gel to the skin of 45 other men. Neither the men, nor the researchers, knew which gel was applied to which study participants.

All of the men then played games of dice where they could win money. The higher their scores, the more money they received.

The researchers structured the games so that the men had opportunities to lie about their scores. The men played the games alone in separate booths and entered their scores on a computer.

But the researchers knew if the men cheated and found that men with the higher levels of testosterone lied less often than the other men.


The results challenge the belief that testosterone effects are limited to promoting antisocial behavior, the study authors said. They believe, instead, that testosterone may increase pride and the need to develop a positive self-image.

And the small financial gains the men could obtain through lying in this study "were not a sufficient incentive to jeopardize one's feeling of self-worth," study co-author Armin Falk, an economist, suggested in a university news release.

The study was published online in the Public Library of Science journal PLoS One.