New Study Says I Was Wrong About NMN and NR?

Brad Stanfield

Apr 3, 2026

Episode description

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Timestamps:
00:00 The Discovery of Nicotinamide Riboside
01:22 NR vs NMN Debate
02:24 The New NR vs NMN (Bergen) Study
03:15 The Contradictory NR vs NN Nature Metabolism Study
03:51 The Hidden Truth in the Bervin Data
06:37 The Evidence Against NR and NMN
09:38 Conclusion & Key Takeaways

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Here are the links to the research papers referenced in the video:
Brenner 2004 (doi: 10.1016/S0092-8674(04)00416-7) — Discovery of NR as an NAD+ precursor in yeast and humans, establishing the NRK pathway.

Brenner 2007 (doi: 10.1016/j.cell.2007.03.024) — NR extended yeast lifespan from ~13 to ~23 divisions via Sir2 silencing.

Sinclair 2016 (doi: 10.1016/j.cmet.2016.09.013) — NMN in mice mitigated age-related decline: weight, energy, insulin sensitivity, eye function.

Berven 2026 (doi: 10.1016/j.isci.2026.114764) — Phase I crossover trial (n=6): NR produced ~2.3x higher blood NAD increase vs NMN. Also showed elevated NAAD, implicating the Preiss-Handler pathway.

Christen/Nature Metabolism 2025 (doi: 10.1038/s42255-025-01421-8) — RCT (n=65): NR and NMN comparably doubled NAD at 14 days; no significant difference between them. Ex vivo gut data showed NR rapidly converted to nicotinic acid by bacteria.

Princeton 2022 (doi: 10.1016/j.cmet.2022.11.004) — Isotope-labeled NR tracing showed the primary route to host NAD is via gut microbiome conversion to nicotinic acid; antibiotic depletion completely eliminated this.

Japanese 2025 (doi: 10.1126/sciadv.adr1538) — Even IV-administered NMN/NR was dumped into bile and converted to nicotinic acid by gut bacteria, bypassing the gut didn't help.

Skeletal muscle meta-analysis 2025 (doi: 10.1002/jcsm.13799) — 10 RCTs in adults 60+: no significant effect on muscle mass, grip strength, gait speed, or chair stand. Concluded "negligible effect."

Glucose/lipid meta-analysis (doi: 10.1007/s11892-024-01557-z) — 8 RCTs, 342 participants: no significant improvement in fasting glucose, insulin, HbA1c, or any lipid marker.

Long-COVID RCT 2025 (doi: 10.1016/j.eclinm.2025.103633) — NR for 20 weeks tripled NAD levels in long-COVID patients; zero improvement in cognition, fatigue, sleep, anxiety, or depression.

Exercise/NAD 2022 (doi: 10.1038/s43587-022-00174-3) — Exercise-trained older adults had NAD levels comparable to young people, suggesting NAD decline isn't inevitable.

Thumbnail by James Kelly
Video edited by Troy Young
Script by John Milliken

The links above are affiliate links, so I receive a small commission every time you use them to purchase a product. The content contained in this video, and its accompanying description, is not intended to replace viewers’ relationships with their own medical practitioner. Always speak with your doctor regarding the content of this channel, and especially before using any products, services, or devices discussed on this channel.

Mindsip insights from this episode:

Reassess NAD supplements for minimal impact on muscle strength and metabolism

A 2025 meta-analysis of ten trials concluded that NMN and NR supplements have a negligible effect on muscle strength, gait speed, or metabolism in older adults.

#NAD

#supplement

Reassess NAD supplements for long COVID fatigue and mood issues

In a study of long COVID patients, tripling their NAD levels with NR supplements led to no improvement in fatigue, sleep quality, anxiety, or depression compared to placebo.

#COVID-19

#NAD

Focus on gut bacteria over NMN vs NR debate

The entire debate over whether NMN or NR is a better NAD precursor is beside the point because gut bacteria break both down into the same cheaper molecule.

#microbiome

#NAD

Utilize exercise to sustain NAD levels in older adults

Exercise-trained older adults have NAD levels in their muscles similar to younger people, suggesting exercise is a powerful intervention for supporting NAD.

#exercise

#NAD

Rethink expensive NR and NMN supplements due to gut bacteria conversion

Three independent research groups have confirmed that gut bacteria break down expensive NR and NMN supplements into nicotinic acid, a form of vitamin B3 you can buy for a few dollars.

#bacteria

#supplement

Understand NMN processing despite intravenous injection

Even when NMN or NR is injected intravenously to bypass the gut, the body dumps it into bile and sends it straight back to the gut for bacteria to process.

#gut

#microbiome

Identify NAAD as a fingerprint for nicotinic acid conversion

The presence of a metabolite called NAAD after supplementation acts as a fingerprint, proving that both NR and NMN are first converted into cheap nicotinic acid.