The answer is-useless, at least of little use. Generally speaking, these things will have a little effect in the first week of use, and the effect will be less and less after the first week, or even ineffective. These things are all auxiliary tools to lose weight. You should have a reasonable diet and good living habits. The most important thing is to do more exercise. Only with these weight-loss tools can it be effective ~ don't blindly believe these products.