It's generally safe to say that these products never work. Their primary purpose is to make money, and they encourage reselling. I just did a little google research, and all I could find were claims by the sites that sell the products, which should never be trusted because it is biased. You should always look for research on medical websites.
These products contain ingredients which some (or one) studies hinted that they might have a slight effect on weight issues under some circumstances. Does that sound vague enough?
This is usually the case with the majority of weight loss supplements. Since the products are not regulated by the FDA, the manufacturers play up the claims to increase sales.