Alcohol use affects all three parts of the hypothalamic-pituitary-gonadal (HPG) axis, a system of endocrine glands and hormones involved in male reproduction. Alcohol use is associated with low testosterone and altered levels of additional reproductive hormones. Of the three components of the HPG axis, the hypothalamus and the pituitary gland have solely regulatory functions, which are mediated by the hormones they produce and secrete. The third component-the testes-also produces key hormones, induding testosterone, which control male sexual characteristics and behaviors. In addition, the testes are responsible for sperm production.

Even though testosterone is often referred to as a “male sex hormone,” it is in actuality common to both genders of animals and humans. The overwhelming majority of research conducted in the past 25 years in both animals and humans has found that alcohol inhibits testosterone secretion.

Alcohol can interfere with the function of the male reproductive system, and can lead to tissue shrinkage, reduced testosterone production, and sperm abnormalities, in the testes. Low levels of testosterone (i.e., hypogonadism) in adult men have been associated with a variety of medical problems including accelerated osteoporosis, decreased muscle and prostate function, anemia, altered immune function, and decreased reproductive ability. Alcohol markedly affects testosterone metabolism independently of cirrhosis or nutritional factors.

Alcoholic men often present with symptoms of decreased sexual function, such as impotence and infertility. Decades ago it was recognized that alcohol per se is a testicular toxin, with low testosterone levels in alcoholic men, and that alcohol intake may cause a transient acute decrease in blood testosterone levels in healthy nonalcoholic men. Later this acute effect of alcohol was shown to be due to an inhibited testosterone synthesis. One study found an acute increase in plasma testosterone after intake of alcohol corresponding to two or three standard alcohol drinks in healthy nonalcoholic men.

Stop drinking alcohol if you want to preserve testosterone, help prevent impotence and improve your quality of life.