Not yet investigated
What we have so far
Blocking GIP causes weight loss in animals. So does agonising it, in people. Both cannot be simply true, and the field has not resolved it.
This star is on the map because the show intends to take the question apart properly — the trials, how it is actually tested, whether the thing sold is the thing studied. That work is not done yet, and nothing here should be read as a conclusion. When the investigation is published it will appear on this page.