Propanolol and slow metabolism question? (Doctors only question or nurses or med student)?

I did what I should not have done and looked up the side effects of propranolol online and found out that propanolol slows down metabolism. However it's not a 100percent proven exactly as it seems. They just list it can possibly lead to weight gain as a possible side effect. Honestly I just need to make the choice to exercise so that is my choice. I don't want to blame the propanolol or anything. It just seems that there are investigations going on about the metabolism. Does that mean that Propanolol slows metabolism? I just want to make sure that the side effects of it doing that are not a fact and that I can just put to rest these panic attacks I'm having mentally because it is driving me crazy. The real question is : IS IT MORE OF AN OPINION/ASSUMPTION THAN A FACT THAT IT SLOWS METABOLISM? because everyones body is different Thank you!