Jab that could help you drop two dress sizes

London: A diet drug that helps women drop two dress sizes in six months could be available in just three years.

The jab has produced "phenomenal" results helping men and women who have struggled with their weight for years shed a stone and a half (or roughly 9.5 kg).

This makes the drug, called liraglutide, more than twice as good as anything on the market.

It also lowers blood pressure, raises good cholesterol, and can prevent and even cure diabetes, reports the Daily Mail.

And it could even make dieting a pleasure, with slimmers who take it saying it produces a 'feel-good' effect.

Liraglutide is already used to treat diabetes. Its manufacturer, Danish firm Novo Nordisk, is carrying out large-scale, definitive trials on 5,000 obese men and women.

These are expected to finish in 2013, the company says.

If they prove as successful as those already carried out, the drug could be routinely given to the overweight and obese in three years.

Researchers have already tested liraglutide on more than 550 obese men and women.

Some were given daily doses. Others were given dummy pills or orlistat, the ‘gold standard' obesity treatment regularly prescribed by general practitioners.

Those who took liraglutide lost an average of a stone and a half (approximately 9.5 kg) over six months - more than twice as much as those on orlistat.

In addition, 28 percent of those on the highest dose of liraglutide shed at least 10 percent of their body weight - almost three times the figure for orlistat.

The women dropped an average of three inches from their waistline, while male potbellies also shrank.

When they continued to take the drug for a further 18 months, the weight stayed off. But those on orlistat began to pile the pounds back on. The results were released at an obesity conference.

Liraglutide, which, like insulin, can be injected from a pen, is based on a gut hormone which tells the brain that it is time to stop eating but is broken down within minutes of being produced. In contrast, the drug stays in the body for hours.