In men, testosterone deficiency reduces libido and penile sensitivity. Chronic diseases such as chronic kidney failure, cirrhosis of the liver, alcoholism, hypothyroidism, etc. can reduce the sexual desire in men, as well as depression and other psychological causes.

Erectile Dysfunction (impotence) means that the penis becomes flaccid again after a short time or does not become stiff at all during an erection. Although sexual desire is often still present, satisfying sex is often no longer possible. Men of all ages can be affected, but potency problems increase with age. With increasing age, the probability increases that organic causes are the trigger of impotence. Next to diseases like diabetes or vascular problems, there can be psychological causes. If the erection fails once or only occasionally, reasons for this can be stress or tiredness.