First of all you have to remember one thing, supplements are just that, supplemental. You are using them to supplement the hopefully healthy lifestyle that you are aspiring to live, namely, a healthy nutrition plan, effective regular exercise, and plenty of rest. If you aren't doing those, forget the supplement. You are adding gas to a car that won't start. Secondly, does that supplement support something you're lacking or enhance what you are already doing. For example, are you taking a green nutrition supplement because your nutrition plan is a little low on green nutrition or do you take an energy booster prior to a cardio workout to help get you going.
The literature says that garcinia cambogia helps suppress appetite by raising serotonin levels. I do believe that but if you are taking it in place of a good nutrition plan, beware. You won't get the results you want because WHAT YOU EAT IS THE KEY TO WEIGHT/FAT LOSS! If you are taking it along with a healthy meal plan, it is likely to accelerate your results.