After adding non-essential amino acids to 293t cells, the cell state looks good within one to two generations, but then deteriorates sharply. What is going on?
NEAA isn't required for quite robust cells like HEK293 and their derivatives. Most labs do not need to add NEAA to keep their cultures going and HEK293 cells can be easily propagated and cultured without NEAA being required. If the lab has been using non-NEAA added MEM (DMEM), then go without it. Most NEAA will change the pH of the media as well when added in sufficient amounts (typically >1% total volume) and could affect the cells that way. I would say to propagate them with and without NEAA for a short time and see how they behave.