How are you cycling your clen? I prefer two separate methods... 2 days on/2 days off is my favorite... and then 2 weeks on/2 weeks off... I can run the first for about 8 weeks, the second I've topped off at 13 weeks. Your body will adjust to the clen... it needs to adjust to clen, especially if you work! If you run a moderate clen cycle you can do the 2 day on/off... if you run a high cycle you need to run the 2 week on/off to allow yourself to cycle up and down. If you're running good clen 75mg is going to give you wicked jitters right off, especially if you've never cycled or are just starting a cycle. You can get yourself up to some pretty high doses (ie: 200mcg/day) but you cant just jump around with those numbers. You'll end up making yourself sick on the couch if you do that... I had a love/hate relationship with Clen. I ran cycles for a year before I knew anything about Taurine and then I picked up some bottles 60mL @ 400mcg/mL and I couldn't dose it small enough and ran a super high cycle and it just burned me out. I never touched it again. Grown men in the gym wouldn't touch that fire water, I couldn't even give it away. So now It's left a bad taste in my mouth (pun, haha). To this day I prefer ECA and ECYA stacks. I am about to run an ECA actually... am waiting for the ephedrine to come in. You can run them longer, you get less side effects, you don't get the "caffeine drop" feel if you don't split doses and let the half life expire and you don't get the return weight gain. IMO.