Ephedrine promotes modest short-term weight loss, specifically fat loss, but its long-term effects are unknown. In mice, ephedrine is known to stimulate thermogenesis in the brown adipose tissue, but because adult humans have only small amounts of brown fat, thermogenesis is assumed to take place mostly in the skeletal muscle.
Ephedrine also decreases gastric emptying. Methylxanthines such as caffeine and theophylline have a synergistic effect with ephedrine with respect to weight loss. This led to creation and marketing of compound products.