Testosterone has long been associated with risk-taking, competitiveness, and generosity, but a new large-scale study suggests these links may be overstated. Researchers from the Stockholm School of Economics (SSE) in Sweden and Nipissing University in Canada report that men who received testosterone exhibited economic decision-making patterns indistinguishable from those who received a placebo.
The study, published in the Proceedings of the National Academy of Sciences (PNAS), is the largest of its kind, involving 1,000 men aged 18 to 45 recruited from three Canadian locations between 2018 and 2023.
Participants were randomly assigned to receive either a single 11-milligram dose of testosterone or a placebo, administered nasally in a double-blind setup. After a 30-minute period to allow the hormone to take effect, participants engaged in a series of established behavioral economics tasks designed to measure risk-taking, generosity, competitiveness, and fairness preferences.
Despite the widespread belief that testosterone can influence economic behavior, the researchers found no statistically significant differences between the two groups across nine primary outcome measures. Men who received testosterone behaved, on average, the same as those in the placebo group.
“This is an important finding because it directly challenges the assumption that short-term testosterone fluctuations drive economic risk-taking or competitiveness,” said co-lead author Justin M. Carré, Professor at the Faculty of Arts and Science at Nipissing University.
The study addresses a major limitation of earlier research, which often relied on small sample sizes and potentially biased analyses. “Previous studies suggested that testosterone might impact willingness to take risks or compete economically,” explained co-lead author Anna Dreber, Professor at the Department of Economics at SSE. “By preregistering our analysis and using a substantially larger sample, we provide strong evidence that short-term testosterone boosts do not meaningfully alter men’s economic choices.”
The researchers emphasized that the findings do not rule out all behavioral effects of testosterone. The experiment tested only a single dose at a specific time, leaving open the possibility that different dosages or long-term hormonal changes could produce different outcomes. Additionally, women were not included in the trial, highlighting the need for further research in broader populations.
Magnus Johannesson, co-lead author and Professor at SSE, noted, “Our study underscores the importance of replication with larger samples and preregistered designs. Effects reported in small-scale experiments can disappear when tested rigorously.”
This collaborative effort also included researchers from the University of Pennsylvania, University of the Fraser Valley, Osaka University, University of Colorado, University College London, and Oakland University. Funding was provided by multiple organizations, including the Jan Wallander and Tom Hedelius Foundation, Knut and Alice Wallenberg Foundation, Marianne and Marcus Wallenberg Foundation, Riksbankens Jubileumsfond, the Natural Sciences and Engineering Research Council of Canada, Japan Society for the Promotion of Science, NSF Early Career Development Program, and The Wharton School Dean’s Research Fund.
The findings challenge popular assumptions about testosterone’s influence on economic behavior, offering a more nuanced understanding of the hormone’s role in human decision-making.
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