I know this doesn't answer your question, but...
From my research coupled with anecdotes like this, and personal history of "heart problems", clen scares the shit out of me. I'd rather dabble with death and choose DNP over clen.
But, there is an alternative: albuterol. I'm 1.5 weeks in my first cycle and have lost nearly 4kg.
None of the sides described by most, even with caffeine, but adequate progress nonetheless. I'm not unimpressed by the mirror results at all, either.
You should give it a go.