The rumor surfaces periodically in the NAD+ conversation — the suggestion that supplementing with NAD precursors could somehow feed cancer cells. It moves fast through the wellness and longevity communities and loses precision at every step. I went looking at where it actually traces back to.

The concern originates in research on cellular metabolism. NAD is deeply involved in energy production and DNA repair pathways, and investigators studying cancer cell biology have observed that rapidly dividing cells draw heavily on those same processes. That is the kernel the rumor latches onto. What the published literature actually examines is considerably more layered: the studies most often cited are in vitro experiments or rodent models, and the authors themselves tend to frame findings as preliminary and highly context-dependent. The popular summary flattens that nuance into something simpler — and scarier — than what the papers describe.

The video below walks through where that research stands, what specific work the alarm draws from, and why the leap from “NAD participates in cell-energy processes” to “NAD supplementation causes cancer” involves inferential steps the researchers themselves are not endorsing. The literature on this is live and unsettled. That is actually the point — the honest read is that the question is still being examined, not that it has been answered in either direction.