It is true, and this is one of the reasons why clenbuterol is not the best choice for fat loss. It will cause lots of side effects, and at the same time the results won't be long lasting. In addition to that, it will also reduce your lean mass - not only fat. And it also raises cortisol levels, which is not healthy. All in all, I don't think that clenbuterol is such a good choice nowadays, when we have such good alternatives as Cardarine GW or SR9009 - these will help with fat loss big time, but without any side effects or raising cortisol levels. Consider using those - it would be a much wiser decision.