Testosterone is one of the steroid hormones (i.e. androgen). Early research has shown that testosterone played a large role in the human aggressive and impulsive behavior. There is increasing interest in the effects of testosterone on human decision-making, including social (i.e. trust, cooperation, altruism, and competition) and economic decision-making (i.e. risk taking). In general, there is a positive association between testosterone level and risk-seeking behavior in economic decision-making. In the social domain, high testosterone levels are associated with more aggressive, dominant, and fairness behavior. Testosterone administration also reduced interpersonal trust. Note that some findings are hard to replicate, and more research is needed to investigate potential moderators. Future research could fruitfully explore the role of testosterone in consumer decision-making, adolescent’s social behavior and clinical application.