A new obesity drug that could hit the market in the next couple of years may allow double the weight loss of current treatments, according to researchers in Denmark.

They said in the British journal Lancet that tesofensine has been shown to be safe in animals and should move to wider testing in people.

The drug works by suppressing hunger, and they said that when it was tested against Parkinson's and Alzheimer's diseases, it caused unintended weight loss.

In a study that ended with 161 patients in Denmark, patients were given either a placebo or one of three dose sizes of tesofensine for six months. People who took the lowest dose lost an average of three times more weight than those given a placebo. The higher dose someone took, the more weight they lost, on average.

The most common side-effects caused by tesofensine were dry mouth, nausea, constipation, hard stools, diarrhea and insomnia. Also, those who took the highest does saw a rise in blood pressure.

The study was written by written by Professor Arne Astrup of the University of Copenhagen.