Losing interest in sex can occur at various times of life and is often normal and transient. However, if this has lasted for more than six months or you have any concern it may be worth discussing with a doctor. Possible underlying causes include low testosterone (Testosterone Deficiency), thyroid disease, diabetes, stress, anxiety, depression, some medications, alcohol, recreational drugs, and more.
ED often occurs because of a diminished blood flow and PDE5 inhibitor drugs taken orally can help restore the supply for some men. But if the blood vessels surrounding the penis are narrowed, its likely other blood vessels are too- a problem with the penis can sometimes be an indicator of an underlying cardiovascular problem. ED can also result from diabetes, prostate problems or be the side effect of other prescribed drugs such as antidepressants.