Of the 23 trials they identified, 12 were methodologically sound enough to include in their analysis. The analysis revealed that some statistically significant weight loss occurred, but the magnitude of the effect is small and the clinical relevance is uncertain. They also found that gastrointestinal adverse events were twice as likely in the hydroxycitric acid group as in the placebo group.
When you are considering the potential benefits of products look for meta-analysis studies that take in all the sound research available. One-off studies that get a significant result are not evidence of anything.