David A. SinclairPhD · Professor of Genetics, Harvard Medical School
Makes the case for them
What it rests onSirtuin and NAD biology, and mouse work on endurance. He attaches an unprompted cancer caveat to his own position in the same episode.
Source: lifespanpodcast.com ↗
Matt KaeberleinPhD · biogerontologist
Does not take them and says so by name
What it rests onHe is a geroscientist who studies the mechanisms these compounds target. He also hosted the field's most persistent NAD sceptic for an episode framed as an unresolved disagreement about whether sirtuins regulate longevity at all.
Source: podcasters.spotify.com ↗
Both are addressing a general adult population and neither states a population caveat, which is unusual, and makes the collision unusually clean. The one asymmetry is that Sinclair is talking about a compound and Kaeberlein is mostly talking about a category: his answer to NMN specifically is the same as his answer to fisetin, urolithin A and proprietary blends, so it is not a targeted objection.
They agree that the human evidence is not settled. Sinclair says so in the same episode where he recommends the compound; Kaeberlein says so as his reason not to take it. The disagreement is entirely about what to do while the evidence is unsettled, which is a values question as much as an evidence question, and both of them know it.
An adequately powered randomised human trial of an NAD precursor with a functional endpoint rather than a biomarker. Both sides would move on the same evidence, so this is a live question rather than a permanent standoff.
You do, and your call is dated, kept, and yours to change. Follow the people you already trust and what they publish turns into a short daily practice.
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