According to some studies in rats, it can inhibit a fat producing enzyme called Citrate Lyase, making it more difficult for the body to produce fat out of carbohydrates (1). Other rat studies show increased levels of the neurotransmitter serotonin.
This could theoretically lead to reduced appetite and cravings (2). There are actually a whole bunch of studies in rats showing that Garcinia Cambogia consistently leads to significant weight loss (3, 4, 5, 6). However, what works in rats doesnt always work in humans.