The breast milk hormone responsible for stimulating breast development and milk production in women is found to be the major culprit of erectile dysfunction and other sexual issues in men. Low levels of prolactin may impair men’s sexual functioning as well as their psychological health, according to a recent study.

Prolactin is released by the pituitary gland as well as throughout other parts of the body, including the uterus, immune cells, the brain, breasts, the prostate, skin and adipose tissue in both men and non-pregnant women, according to You and Your Hormones, the official public information website of the Society for Endocrinology. The hormone is released into the bloodstream and circulates in the human body.

High levels or prolactin may lead to a condition called hyperprolactinaemia, which is commonly caused by pregnancy, medications that reduce dopamine action in the body, thyroid underactivity, and benign pituitary tumors. Female patients with hyperprolactinaemia may experience unwanted milk production, disturbances in their menstrual cycle, and symptoms of estrogen or testosterone deficiency. While high levels of prolactin have been associated with impotency in men, low levels of the hormone have now been found to increase sexual dysfunction.

Researchers sought to investigate how levels of prolactin affected men’s sexual and psychological health. Nearly 3,000 men between the ages of 40 and 79 years old were measured for their testosterone and prolactin levels, body mass index (BMI), and blood cholesterol and sugar levels.

The participants were asked to fill out questionnaires about their general health, particularly about smoking, alcohol consumption, and sexual functioning in order to determine factors that trigger sexual problems in men. The McKinley Health Center at the University of Illinois at Urbana-Champaign says too much alcohol consumption may alter sexual response, which may cause anxiety for men when they try to attain an erection in the future.

Prolactin levels were shown to play the biggest role in the participants' sex drive. Men with low prolactin levels were found to have more issues with sexual health, as well as psychological health. The participants who had lower than average levels of the hormone — but still within the normal range — reported their sexual issues becoming increasingly worse, including their ability to orgasm. The researchers found health issues such as high BMI, lower levels of exercise, and feeling unhealthier were prevalent in men with less prolactin when compared to their counterparts, LiveScience reported.

These findings contradict the well-accepted idea of high prolactin levels being linked to men’s sexual issues. The results of this study suggest that the hormone could have a positive impact in initiating or stabilizing male sexual behavior. The study does not prove a cause-and-effect relationship between prolactin and sexual functioning. The researchers speculate that low prolactin reflects a change in the levels of signaling chemicals in the brain that are responsible for regulating sexual behavior. Also, poorer physical and mental health could be an underlying reason for low prolactin and a lower sex drive, said the researchers.

Another study on prolactin levels found that participants between the ages of 65 and 70 who were married, physically healthy, and had no psychopathology or marital problems, had decreased libido when their levels of the hormone were high. Mild hyperprolactinaemia in aging men may possibly be associated with decreased sexual desire and frequency of sexual activity as suggested in this study.

The two studies provide contrasting findings of prolactin levels and its effects on male sexual behavior which may lead to the possibility of conducting further studies to further examine this indirect relationship.

To learn how you can find out your prolactin level, click here.

Source: Corona, G, Rastrelli, G, Wu, FC, et al. Low Prolactin Is Associated with Sexual Dysfunction and Psychological or Metabolic Disturbances in Middle-Aged and Elderly Men: The European Male Aging Study (EMAS). Journal of Sexual Medicine. 2013.