Studies that claim to have found weight loss were carried out on animals. Studies involving humans are for the most part badly designed. A few quality studies have been carried out over the years, starting in 1998 with a double-blind, placebo-controlled trial of 135 adults over 12 weeks published in The Journal of the American Medical Association.
They found no evidence that hydroxycitric acid, the active ingredient in weight loss products made from garcinia cambogia, produced significant weight loss. The American Journal of Clinical Nutrition in 2004 published a systematic review of meta-analyses and clinical trials on dietary supplements for weight loss by complementary medicine researchers at the Universities of Exeter and Plymouth.