Smoking and alcohol can cause ED. He said: “Alcohol increases sexual desire but decreases a man’s perform­ance.”

Prolonged bicycling -­which puts pressure on a vital artery and nerve near the genitals can also cause the condition. ED can either have mental or physical causes. Pug said that if the patient has normal morning erections, the ED is likely to be psychogenic, or mental, in nature. However, if a man’s morn­ing erections are poor, his erectile problems are prob­ably due to a physical cause. A patient with ED concerns consulting a doctor should expect to discuss his medi­cal history and go through a physical examination, includ­ing a urine test. Png said that properly prescribed medications such as sildenafil (Viagra) and tadalafil (Cialis) can have an 80 to 90 percent successful response rate with relatively minimal side effects. He discourages the use of alternative medicines that claim to boost male virility, especially if they are not from a reputable source.

He said: “These alternative medicines are not worth the risk when ED can be easily sorted out with a visit to the doctor.”