A rub-on gel could be the first over-the-counter treatment for impotency, a company has announced.
Erectile dysfunction is thought to affect one in 10 men
It is being developed by Futura Medical in collaboration with pharmaceutical giant GlaxoSmithKline.
The treatment, called MED2002, is expected to go into clinical trials at the end of 2006.
But the Sexual Dysfunction Association said it is important to await the outcome of these trials to see how effective the product really is.
MED2002, is based on a compound called glyceryl trinitrate (GTN), which has been used to treat angina for the last 40 years. GTN is known to cause dilation of the arteries and increased blood flow.
James Barder, chief executive of Futura Medical, said MED2002 had performed well in early in vitro trials.
The company will now be looking to recruit about 1,500 men to take part in three more clinical studies.
Mr Barder said: "We expect to see this on the market in 2009."
Mr Barder said the treatment would be non-prescription because GTN "is a well known compound and its side-effect profile is well characterised".
But the Sexual Dysfunction Association said it was important to await the outcome of the trials.
A spokesperson said: "The more treatment available the better it will be for any sufferers of erectile dysfunction.
"But obviously any kind of treatment needs to go through a process to find if it is effective or it there are side effects.
"And only after a careful evaluation will we be able to say whether this is a great tool or not."
Erectile dysfunction is thought to affect about one in every 10 men in the UK.
About 70% of cases are believed to have physical causes, and 30% are because of psychological factors.
There are currently three oral drugs licensed for the treatment in the UK of erectile dysfunction: Cialis, Levitra and Viagra.