Impotence or, to give it its correct name, erectile dysfunction affects an astounding one in ten men in the UK.
To date, 15 million men worldwide have depended on Viagra to stop their impotence.
But this summer a new drug, Uprima, was released onto the market which works on the parts of the brain that control smooth muscle contractions to give the same effect as Viagra, only quicker.
Uprima targets the parts of the brain which control the movement of smooth muscle in the penis, stimulating it to relax and boosting blood flow.
Unlike Viagra, which is a pill swallowed with food, Uprima is a tablet that dissolves under the tongue and has an effect in 15 minutes rather than the hour it takes for Viagra to work.
This fast action means that the drug is more spontaneous than Viagra, says Dr Wallace Dinsmore of the Royal Victoria Hospital in Belfast, which can make a difference to some men.
Men who find erectile dysfunction frustrating, embarrassing and hard to talk about, says Dr Dinsmore, may abstain from sex rather than admit to having a problem.
Wives and girlfriends often don't realise there is a physical problem and assume their partners are having an affair or have lost interest.
Viagra and Uprima don't work unless there is some sexual stimulation there to start with, so they are best used by people who do feel sexually stimulated but have erection problems rather than those who suffer from a low libido.
Although impotence can be a cause of low libido in itself because of self confidence problems.
The main cause of impotence, says Dr Dinsmore, is the hardening or obstruction of blood vessels which leads to decreased blood flow.
As it is increased blood flow which causes the penis to become erect normally, a lack of blood can cause erectile problems.