I've taken this drug before - it's quite an upper. I used to take it sometimes (for the wrong, non-asthma-related reasons of course) along with my daily coffee. This would give me tons of energy for workouts, make my muscles stand out more, and make my heart flutter. I've since stayed away from it because the fast, weak heartbeat pattern felt dangerous.
I can see why someone would want to use it for weight loss or cutting, if only to make them feel more energetic when they are training with less calories.
Also, the last time I got it, it was easy and seemingly legal. I don't think mods would want me posting places to get it on here, though.