Not yet investigated
What we have so far
NAD+ is too large and too charged to enter cells intact, so an infusion raises plasma and then the precursors it is broken into. The flush is real; the rationale is not.
This star is on the map because the show intends to take the question apart properly — the trials, how it is actually tested, whether the thing sold is the thing studied. That work is not done yet, and nothing here should be read as a conclusion. When the investigation is published it will appear on this page.