The level of the male hormone testosterone decreases in men once they become married, according to a study recently published in Psychoneuroendocrinology.

Testosterone is a male sex hormone and it serves a number of functions within the male body. Testosterone impacts on reproduction, muscle mass, bone structure and cognitive function. As well as these physiological roles, testosterone is also thought to influence, or be influenced by a man’s social experience. Previously, research has shown that levels of testosterone differ between married and unmarried men. However, in these studies it was not clear whether men with naturally lower levels of testosterone are more likely to become married or whether becoming married actually suppresses the production of testosterone.

In order to determine whether marriage causes a drop in testosterone levels in men, a team of scientists from The University of Copenhagen, Denmark recruited 1,113 men between the age of 30 and 60 for analysis. Testosterone samples were taken from the blood at the beginning of the study and again after 10 years. The samples were then compared to see if any changes in testosterone level had occurred and whether these changes were dependent on the marital status of each individual.

The results showed that men who were unmarried prior to the study who became married during the 10 years between each sample was taken showed the largest drop in testosterone compared to other men. As well as this, men who went from married to unmarried over the 10-year period showed the smallest decline in testosterone.

One explanation for the increased decline in testosterone amongst married men comes from evidence suggesting that testosterone levels increase after a period of sexual abstinence, and scientists have argued that married men have more sexual intercourse than unmarried men. Furthermore, the first sample of testosterone taken could not predict whether the men would be married or unmarried after 10 years, which the researchers claim shows that marital status impacts on male testosterone levels and not vice versa.

The level of testosterone in men naturally declines with age, which is why both groups of men mentioned above showed a decline in testosterone over the 10-year period. But overall, the study provides strong evidence that testosterone trajectories can be influenced by the natural aging process as well as changes in marital status. Men who become married experience an accelerated decline in testosterone whereas men who become unmarried experience a slower decline.