This is what I found on educational institution sites:
I read a fleeting reference (it was in the metadescription of a web site, but when I navigated to the site I got a 404 not found error) that indicated that it reduces hunger pangs. It is known to help improve feelings of well being and energy levels. The improved feelings of well being probably help keep one on track on their diet plan. the increased energy levels could help your burn more energy.
Goji berries are high in antioxidants and some consider them a "fountain of youth." They were used in traditional chinese medicine, usually in combination with other ingredients. The other ingredients in these TCM formulations probably could help with achieving weight loss goals. I would seek a TCM practitioner that is a herbalist and ask them your specific questions as to whether such a formula does exist.
Lastly, I don't think any one thing helps people lose weight, unless it is disease (I went on an involuntary weight loss program with dengue fever during this last Christmas). Changing one's overall dietary intake and exercise are two essential elements of any successful weight loss endeavor.