You are just replacing a meal that you chew with a meal that you drink. Where you might consume 500 calories on a meal that you don't plan, you would consume 300 (example) on a prepackaged drink. So, you cut calories. You lose weight. That's the trick, cutting calories. You don't have to have a liquid meal to do that.
The disclaimer on their site says
"Product must be used with diet and exercise. Weight loss results vary depending on the individual.
For our in-house preliminary study, weight loss averaged 1-2 pounds per week."
So, you still have to follow a diet and exercise program (surprise!) and the average weight loss in their tests is the same as the average weight loss with any other diet that doesn't require the use of expensive products.
If you don't have time to prepare a meal and you like drinking a meal replacement, then this type of product may be for you, though there are a lot of similar products out there which cost less.
Pure Trim is a network marketing product. This is usually a red flag for overpriced, overrated products.
I can't say whether the ingredients in this product are good or bad, because they don't disclose them on their site. That's usually a bad sign, too. What if you are allergic to one of the ingredients?
They don't list refund information, either. However, I will email them to request a list of ingredients, and their refund policy.