Under normal circumstances, when a man becomes sexually aroused or 'gets turned on', a substance called Nitric Oxide (NO) is released in an area of the Penis called the Corpus Cavernosum (see illustration below). However, certain physical or psychological factors can interfere with this natural process and, for whatever reason, men at any time of their lives can find it hard to gain and/or maintain a firm erection. It's up there with the likes of Nike, Coca-Cola, Pepsi and Microsoft as one of the world's most instantly recognisable brands. That's nearly 30 million men in America alone. One particular product above all others has become so enormously popular worldwide it has ingrained itself upon the male psyche like no other brand before it. Extensive trials of Viagra have proven it effective in treating cases of ED caused by other medical conditions. This in turn can have a 'knock on' effect psychologically as the man gets dispirited or depressed at his inability to 'perform' which can further exacerbates the problem. Then we'll take a look at what Viagra is and what it does and hear from some people who have already used this little pill that has literally revolutionised their sex life. Studies in the United States
