Speaking of taking NAD precursors, Steve Horvath (of 'grim clock' fame) made an offhand comment in an interview with Rhonda Patrick that niacinamide could inhibit SIRT1 production. I was in the middle of a long car trip so I couldn't take notes, but he mentioned that it was part of a feedback loop.

In process of tracking that down, I ran across this pubmed article, Nicotinamide is an inhibitor of SIRT1 in vitro, but can be a stimulator in cells https://pubmed.ncbi.nlm.nih.gov/28417163/

This is marginally off-topic, so it likely counts as yet another interruption.