Ephedrine is usually taken with a caffine & aspirin mix for best results.

From memory it goes something the caffine is a natural appetite suppressant and the aspirin thins the blood. Your body temp will raise by a degree or two constantly and this is what burns extra callories. I think it also makes your heart pulse quicker, raising blood presure and causing faintness & dizzyness. You will also have trouble sleeping too.

The Ephedrine releases hormones (beta I think) which aid the fat breakdown & burning process.

If you are a "slight" female I would strongly suggest taking half the dose instructed to start out. My missus didn't get on with at all when she took a very low dosage.