The plant Ephedra sinica’s main proposed active ingredient for weight loss is ephedrine, which is often taken in conjuction with caffeine. Its proposed mechanism of action for weight loss is that it enhances and speeds up metabolism, promoting a fat-burning metabolic state . Thirty-one RCTs published between 1975 and 2017 were identified, among which 10 studies had a low degree of bias (31%). Fourteen (45%) were conducted in the United States, whereas eleven (35%) were conducted in Europe. Funding sources were not revealed in two studies, with industry sponsoring ninteen (61%) studies. Study duration ranged from 1 week to 9 months, the number in each arm ranged from 4 to 84 participants, and most were conducted in women. What Are The Top 2 Fat Burning Appetite Suppressant Pills No participants were aged >50 years (range, 22-50.1). Fourteen (45%) studies noted pre/post significant weight changes between arms over time; however, eleven studies did not report such outcomes. Of the 10 studies showing a low risk of bias , 5 reported statistically significant decreases in weight ranging from 0.3 to 4.9 kg; results on intergroup pre/post weight changes were otherwise not reported .