We wouldn't sell it if we didn't think it was safe.
Originally the choice for 3,3-diiodothyronine was because it didn't negatively effect TSH like 3,5 did so there was no reason to suspect possible weight rebound after finishing the product.
Our product Shift is solely a 3,3 product at the same dose as Alpha-T2 but without the rauwolscine and higenamine. Here are a few reviews of that product in particular that will help you address the "does 3,3 cause fat loss" concern.
PES SHIFT Reviews
Alpha-T2 is a stronger product and the rauwolscine and higenamine combination is effective for appetite suppression in most users. If you have used one bottle of OEP I would probably extend the run and add Alpha-T2 for the "Get Up and Go Stack".
I hope this helps.