well, i finished my first tryout of clen a little over a week ago now. though it definitely helped, it was a little dissapointing compared to what i was expecting from the hype. here's my peronal experience while on it...
only used it for 2 weeks cause of concerns for sides (mainly concerns for the heart issues), but within those two weeks my weight stayed the same and i dropped about 2.5%bf. considering since my weight stayed the same and my bf went down, obviously not only did i not lose muscle while on this, but i actually gained some muscle in the process.
now on the bad side. i did only lose 2.5%bf, which was a little dissapointing considering how low my calories were while on this diet. also, i eventually upped my dose to the max i could tolerate which was 100mcg, and there was no possibility of me going higher cause this dose was giving me a lot of anxiety. at this dose, i had very few of the typical effects you're supposed to experience with clen (increases in rhr, bp, or body temp). i do know from the other sides i experienced this stuff was real, but not sure why it never increased my temp, as i thought this was the main way it went about burning the extra calories.
one piece of advice i'd like to give you all is do not take this stuff before doing any kind of intense cardio. i was doing cardio in the mornings for about 45mins 3 days a week, and after a thread i read in these forums i thought i might take my clen before my cardio for an extra "kick". well, i was doing my cardio at a pretty high hr at the time (about 160bpm), and about 30 mins into my cardio that morning i was completely exhausted and got lightheaded. i started to slow down my pace to do a cool-down and my chest was feeling very funny. not pain, but just a very odd feeling like something was just, wrong. really freaked me out, but luckily it went away after about 20mins or so of rest.
my sides while i was on were: anxiety, occasional insomnia, hands were a little shaky, slight pressure feeling in center of chest, and that's about it as far as i can remember right now. all in all, the sides were pretty tolerable, but the anxiety was pretty bad. i might consider a slightly lower dose next time just because of that alone.
well, hope this helps some of you considering clen or have had similar sides to know that you weren't the only one. i considered clen better than eca, but only cause of the fact it not only prevented but helped me actually gain muscle while on a very low-calorie diet.
next time i use a cutting agent, it will be t3 to see how my body reacts. after that, i'll try the combo of these two saying as the one with the main concern is clen and i did that and came out fine. i'll let you guys know how those 2 cutting cycles work out for me down the road.