An experimental study on young males showed that applying a single dose of testosterone in the form of gel to participants upper arms and shoulders reduces their willingness to delay gratification of sexual impulses. The study was published in Psychoneuroendocrinology. Testosterone is the major sex hormone in males. Produced mainly in the Leydig cells of testes, it plays the primary role in sexual differentiation and functioning. In many mammals, it regulates both the ability to engage in sex and sexual desire. Studies on humans have revealed that it also has a role in decision making and psyc…