With clen, many of the sides are dose related. I suggest that you start low, 40mcg and add 20mcg every 2 wks, going no higher than 120mcg. Much better/safer method and sides are lower! No need for high doses when low doses work. As you get used to it, increasing the dose will not be overwhelming. Stims are not great for your heart but if you control your dose and use for 16 wks a year, I would not expect it to be a problem for an otherwise heathy person. You can also look into ECA, which some prefer. You can add yohimbine to either of these stacks. When you do, do it after you are used to the effect of the fat burner, then add 2.5mg to start. Then increase over time, as you adjust. 

For anyone interested in making optimal progress and building a foundation for even better future progress, reach out to me at the Next Level Nutrition page, here at Naps Gear, to talk to me about my coaching services.