I am working with HepG2 cells to observe effects of Simvastatin treatment on the cells. We are aiming to identify a dose response associated with levels of ATP, metabolic activity, and CoQ10 depletion. I have been getting inconsistent results. After months of exhausting all avenues of the cause of inconsistency I am at a loss for what could be going wrong. I have gained the results that are expected a few times, higher treatment causing less viable cells and higher ATP depletion. But not enough to feel comfortable moving forward with my research. Any suggestions? Thank you!