Anyone familiar with this stuff ?

In late 2012, a United States television personality, 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, clinical trials do not support claims that Garcinia camobogia 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 However, side effects—namely hepatotoxicity—led to one preparation being withdrawn from the market.
A 1998 randomized controlled trial looked at the effects of hydroxycitric acid, the purported active ingredient in gambooge, 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".