Podcast summary & analysis
Is 'running out of NAD+' why we age, and can supplements fix it?
NAD+ and cellular repair are real, active science, but the leap to supplements slowing or reversing aging goes beyond the human evidence.
Anti-aging supplements are a booming market, and NAD+ is a favourite selling point. Knowing that the underlying biology is genuine but the human proof is thin helps you take the interesting science seriously without overspending on unproven pills. Some of the advice, like reducing inflammation and staying active, is worthwhile regardless.
What this episode covers
- Andrew Salzman describes aging as a slow failure of the body's repair systems, centred on a molecule called NAD+.
- He explains that NAD+ is central to cellular energy metabolism and is used by enzymes involved in DNA repair and cellular stress responses, and proposes that chronic inflammation and a 'leaky gut' 'drain' it, a 'hole in the bucket' that leaves the body unable to rebuild itself.
- To counter this he suggests reducing inflammation through gut health, using creatine to deliver energy to demanding tissues like the brain, and considering NAD+ 'precursor' supplements such as NR or NMN.
- The underlying biology is real and actively studied, and NAD+ levels decline with age in many tissues and models.
- But the inflammation-drains-NAD+ chain, and the jump to supplements meaningfully slowing or reversing aging in people, are not established by strong human evidence.
Confidence in this episode
Everything about how much to believe this episode, in one place.
The core biology is strong: NAD+ is central to energy metabolism and repair-related enzymes, and declines with age in many tissues and models. Much weaker is the chain from inflammation to NAD+ depletion to aging, and the claim that supplements slow or reverse aging in people, where human trials are small and mixed. Anti-aging supplements are also heavily marketed.
- NAD+ is central to cellular energy metabolism and to enzymes involved in DNA repair and stress responses.
- NAD+ levels decline with age in many tissues and experimental models, with more limited human data.
- Creatine has strong evidence for strength and muscle performance, and some emerging cognitive evidence.
- Whether chronic inflammation meaningfully depletes NAD+ in humans in a way that drives aging.
- Whether reducing inflammation, or a 'leaky gut' chain, restores NAD+ enough to change aging outcomes.
- Whether NR/NMN precursors, beyond shifting NAD-related biomarkers, produce clinical benefit or slow human aging.
What stands out
- NAD+ does decline with age in many tissues, but that does not prove a supplement will slow aging.
- A supplement can shift an NAD-related biomarker without changing any health outcome, they are different steps.
- Creatine's strong evidence is for strength and muscle, not for slowing aging, don't blur the two.
See the broader evidence
1Best-supported action
The single highest-leverage move from this episode, anchored in the strongest evidence the speaker presents.
Consider the well-supported basics for healthy aging, exercise, sleep, and a good diet, before spending on NAD+ or 'anti-aging' supplements.
2Where to start
Small low-friction starters covering the main moves from this episode.
- Prioritise regular exercise, good sleep, and a healthy diet.
- Support gut and metabolic health with whole foods and fibre.
- Be cautious with pricey 'anti-aging' supplements.
3Other supported actions
Further actions discussed in this episode, ordered from strongest to weakest evidence. This is one expert's view, the full topic compares and ranks across experts.
- Start with the well-supported basics for healthy aging: regular exercise, good sleep, and a healthy diet.Strong evidence
- Consider creatine if muscle or strength is a goal, which has solid evidence, separate from any anti-aging claim.Moderate evidence
- Treat NAD+ 'precursor' and other anti-aging supplements as experimental, and ask your doctor before spending on them.Limited evidence
4See the broader evidence
Questions worth asking your doctor
- Given my health, are NAD+ or related supplements likely to help me, or just costly?
- Given the claims, what lifestyle steps actually support healthy aging?
- Given my medicines, could any of these supplements interact with them?
Full doctor prep with ranked questions available in the full topic page
Context
Dr. Andrew Salzman is a physician and researcher focused on cellular energy and repair, who frames aging around NAD+, PARP enzymes, and DNA repair. He is strong on the real, active science of NAD+ and cellular repair, which does decline with age. He tends to extend that biology into confident claims that supplements can slow or reverse aging, which the human evidence does not yet support, and he has commercial interests in this space, so weigh product-specific recommendations critically.
NAD+ is central to cellular energy metabolism and is used by enzymes involved in DNA repair and cellular stress responses. Its levels decline with age in many tissues and experimental models, including some human data, although the size and consistency of that decline across human tissues is still being defined. NAD+ is not one circulating pool that drops uniformly through the whole body.
The 'inflammation drains NAD+, so reducing it refills the bucket' story is a mechanistically plausible pathway, not a demonstrated aging mechanism. Inflammatory and oxidative stress can activate NAD-consuming enzymes (like PARPs and CD38), but whether chronic inflammation meaningfully depletes NAD+ in humans in a way that drives aging, and whether lowering inflammation restores it enough to change aging, is uncertain.
The 'leaky gut, inflammation, NAD+ depletion, aging' chain is a proposed mechanism, not an established clinical pathway.
On supplements, precursors such as nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN) are the main ones studied. Some can raise NAD-related biomarkers in humans, but whether that produces meaningful clinical benefit, or slows human aging, is not established. Changing the biomarker is not the same as changing the outcome.
Creatine has strong evidence for specific outcomes such as strength and muscle performance, and some emerging cognitive evidence; that is different from evidence that it slows aging. This is general information, not medical advice.
Where people go wrong
- Buying NAD+ precursors expecting to slow aging because they can raise an NAD-related biomarker.A biomarker shift is not proof of benefit; you may spend a lot with little human proof.
- Skipping the proven basics because a supplement sounds high-tech.You may miss the changes that actually help.
What to expect over time
- StartBuild exercise, sleep, and diet habits that are proven to support healthy aging.
- OngoingConsider creatine for muscle goals; keep it separate from anti-aging hype.
- Before buyingTreat NAD+ supplements as experimental and check with your doctor.