In late 2012, Dr. Oz, promoted Garcinia cambogia extract as a "magic" weight-loss aid. Dr. Oz's previous endorsements have often led to a substantial increase in consumer interest in the promoted products. However, there is a dearth of scientific evidence, and clinical trials do not support claims that Garcinia cambogia is an effective weight-loss aid. A meta-analysis found a possible small, short-term weight loss effect (under 1 kilogram). However, side effects—namely hepatotoxicity (chemical-driven liver damage)—led to one preparation being withdrawn from the market.
A 1998 randomized controlled trial looked at the effects of hydroxycitric acid, the purported active component in Garcinia gummi-gutta, as a potential antiobesity agent in 135 people. The conclusion from this trial was that "Garcinia cambogia failed to produce significant weight loss and fat mass loss beyond that observed with placebo".
So , similar to the HCG drops and the Raspberry Ketones put out there, there is no clinical evidence that it works.
What usually happens is that along with the drops or pills you have to do a reduced diet and this is what causes the weight loss , not the magic pills.
Garcinia is actually a purgative, or laxative so that is possibly another reason why some think it works.
Save your money, learn to eat only real natural foods that are nutritional for you. Cut out processed foods and all things 'white', sugar being the worst.
Eat under your RDI and this should help.
best of luck.
If it is a plant, eat it, if it comes from a plant, don't!