They were dubbed weight-loss wonder drugs when the prescription Phen-Fen arrived in the early 1990's, proving to be the most powerful appetite suppressant ever to hit the market.

It was so successful at inducing weight-loss that clinics rose up around the country devoted to prescribing Phen-Fen. Heart valve problems appeared in some patients, leading the FDA to pull the diet drug cocktail. It seemed the Phen-Fen run was over, but now a team at at the University of North Carolina is studying the drug and has been the first to tackle the mechanism behind Phen-Fen's dangerous heart effects.

They say, its a serotonin receptor found specifically in the heart, a discovery hinting at the possibility of a Phen-Fen return. Researchers say it is possible to make a drug that targets the healthy, or magic, receptor for weight gain and misses the receptor for side effects.

Mariale, the first of the reformulated Phen-Fen drugs could hit doctor's offices within the next 3 years.