I used clen in 3 seperate 2 week cycles the last few months and have now started again. I am using like this.....40mcg, 60mcg, 80mcg, 100mcg for 8 days, then come down again to 80, 60 and 40. This is working very well for me. I do have the shakes big time and maybe a few mild headaches which probably come from the low carb intake. I burned up fat big time with this method. Bam