I have tried using NMPP, which blocks the haem metabolic pathway, on T cells, but the results have been inconsistent. In two experiments, NMPP did not inhibit proliferation, while in one experiment, it caused a slight inhibition. I'm unsure whether this variability is due to the reagent degrading over time, as it was ordered in 2022, although I understand that organic reagents typically remain stable. I would appreciate your insights—especially if you've used FECH inhibitor (NMPP)—as it would help me decide whether I should order a fresh batch of NMPP.