Dr Brad Stanfield video on David Sinclair VS Charles Brenner | NMN & NR

I just watched this video: https://www.youtube.com/watch?v=BP3Jq1hL1Ws

Stanfield said a couple of things I found interesting about NMR.  One is that it can't get into cells directly.  It has a phosphate group that needs to be removed first, then the NR can get into the cells.

More interesting than that is that if the cell has too much NMN in it, it self-destructs.

This leads me to doubt that taking NMN is such a good idea.  Comments?