I recently purchased Muscletech's NANO-X9. I have tried other NO products from NO-2, Nitrix, Xpand,and Blits Cylce with out the effects that NANO-X9 give me. It causes my heart to race like taking ephedra and I break into cold sweats. I have tried a lower dose as compared to the recommended dose for my weight. As for the muscle pumps and the 9 second time line it gives you to work or should work its bull. I think this is by far in my opinion the biggest waste of money I have spent on a NO product. Thus far Nitrix and the BSN product line have been my favorites. But, My body is adjusting to them even after cycling of as they recommend. I have tried numerious other supliments with no effect that I can feel what so ever, Seems like everything I use just doesn't work anymore even after the off cycles. Any suggestions on products that have worked for you would be great and much apriciated thank you