UW aging researcher casts doubt on NAD longevity supplements

A University of Washington aging researcher casts doubt on the NAD longevity supplement boom after a Nature Metabolism study found no evidence that NAD+ blood levels decline with age in more than 300 people. Matt Kaeberlein says marketing hype long outran the science behind anti-aging claims. The debate matters for anyone spending on NR, NMN, or NAD infusions promoted by influencers and wellness brands.

Key Takeaways

• A Nature Metabolism study found no evidence that NAD+ blood levels fall with age, challenging a core sales pitch.
• UW affiliate professor Matt Kaeberlein says the idea that NAD always declines with age became dogma without strong human evidence.
• Supplement advocates counter that blood levels may not reflect tissue changes in the brain or muscles.
• Kaeberlein remains on the fence: suggestive studies exist, but large clinical trials proving broad anti-aging benefits are still lacking.
• The study did not prove NAD supplements fail—it undercut one of the most repeated claims used to sell them.

For years, celebrities, influencers, and longevity enthusiasts have promoted NAD+ supplements as tools to slow aging, boost energy, and improve health. The pitch was straightforward: levels of nicotinamide adenine dinucleotide (NAD+) drop as we get older, and restoring them could fight the aging process.

That logic helped fuel a booming longevity and biohacking market spanning pills, powders, and IV infusions. Then fresh research landed—and a University of Washington scientist went on Seattle Red 770 AM to explain why consumers should pause before treating the hype as settled science.

What did the Nature Metabolism study find about NAD and aging?

Researchers examining blood samples from more than 300 people reported an unexpected result: no evidence that NAD+ levels decline with age. The findings drew national attention, including a New York Times headline suggesting new research had upended the argument for a popular longevity supplement.

That single datapoint strikes at a marketing pillar. If blood NAD+ does not reliably fall over time, the simple replace-what-you-lost story behind many anti-aging products becomes harder to defend.

Why does a UW aging researcher cast doubt on NAD supplements?

Matt Kaeberlein, an affiliate professor at the University of Washington who studies aging, told The Jason Rantz Show that NAD remains vital biology. He described it as a buffer for cellular energy, involved in thousands of chemical reactions tied to ATP—the cell energy currency.

Where he pushes back is on the leap from molecule to miracle. The dogma has become this idea that NAD levels decline with age, and therefore if we replace NAD, that will be beneficial, Kaeberlein said. The problem is that that dogma has not really been well supported by evidence in the scientific literature.

He also suggested some sellers are moving the goalposts. My perception is those people who are trying to sell you on NAD have changed their tune because the data did not match what they wanted to be true, he said.

Are NAD longevity supplements proven to work?

Not for most people, according to the cautious read Kaeberlein offered on air. Many NAD supporters argue the Nature Metabolism paper only measured blood, not tissue levels in organs such as the brain or muscles—where some prior work has suggested declines might still occur.

Kaeberlein acknowledged the open questions. NAD might matter in specific tissues, and extra NAD could still help even if baseline levels do not fall—researchers simply do not know yet. He also noted a plausible reason some users report better energy: NAD may become limiting in people with mitochondrial dysfunction.

What is missing, he stressed, is solid clinical data. Where I land on NAD is there is a lot of smoke, meaning there are lots and lots of studies that are suggestive, Kaeberlein said. I am on the fence. I want to believe. I am just really waiting for some definitive data to tip me one way or the other.

The latest study did not prove NAD supplements are worthless. It challenged one of the most commonly repeated claims used to sell them—and that alone is enough to make the NAD longevity boom look ahead of its evidence.