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Bottom Line: Studies in rats show that the active ingredient in Garcinia Cambogia can inhibit a fat producing enzyme called Citrate Lyase and increase serotonin levels, leading to significant weight loss. A Look at Some Human Studies Fortunately, I also found several human studies on Garcinia Cambogia. All of these studies are so-called randomized controlled trials, which are the gold standard of scientific experiments in humans.
The biggest of the studies included 135 overweight individuals, which were split into two groups (7): Treatment group: 1 gram of Garcinia Cambogia Extract, 3 times per day, taken 30 minutes before meals.