New Study Says I Was Wrong About NMN and NR?

The speaker builds the case that the entire NR vs NMN debate is moot because both compounds are pro-drugs for nicotinic acid. Three independent research groups have confirmed that gut bacteria rapidly convert NR and NMN to nicotinic acid. Even intravenous administration results in biliary excretion back to the gut for bacterial conversion. Since the body ultimately uses cheap vitamin B3 to make NAD, there is no biochemical advantage to paying a premium for NR or NMN. The speaker's personal decision to include nicotinamide in his own supplement reflects this evidence. He emphasizes that meeting baseline B3 requirements is sufficient, and that the supplement industry's narrative of superior absorption is not supported by human data.

After dismantling the case for expensive NAD precursors, the speaker pivots to exercise as the real solution. He notes that the supplement industry wants consumers fighting over a $60/month vitamin B3 product, while ignoring a free intervention with far stronger evidence. Exercise not only supports NAD but is the most powerful longevity intervention known. The contrast is stark: decades of clinical trials have failed to show that raising NAD with pills improves any functional outcome, whereas exercise consistently improves muscle strength, metabolism, and healthspan. The speaker urges viewers to check out his next video on exercise evidence, positioning it as the actionable takeaway from the entire NAD discussion.

The Bergen study gave 6 healthy adults 1,200 mg/day of both NR and NMN in a crossover design. While the headline result was a 2.3-fold higher blood NAD increase from NR, the researchers also tracked a panel of NAD metabolites. One metabolite, NAAD, is a landmark that only appears when NAD is synthesized via the Preiss-Handler pathway starting from nicotinic acid. After two weeks of supplementation, NAAD levels were significantly elevated in both NR and NMN groups. This metabolic fingerprint demonstrates that neither NR nor NMN is directly converted to NAD inside cells; instead, both are first broken down to plain nicotinic acid—a cheap form of vitamin B3—and then rebuilt into NAD through the Preiss-Handler pathway. The finding aligns with three independent research groups' work showing gut bacteria are responsible for this conversion. The speaker argues that this buried data makes the entire NMN vs NR debate beside the point, as both supplements end up as the same inexpensive molecule before affecting NAD levels.

Since the 2023 video, two more independent groups have confirmed the gut conversion pathway in animals and now in humans. A 2025 Japanese study showed that even when NMN or NR is injected intravenously to bypass the gut, the body dumps it into bile, sending it back to the gut where bacteria convert it to nicotinic acid. The Christian study (the 65-person trial published in Nature Metabolism) took fecal samples from healthy adults, exposed them to NR in a lab dish, and watched the bacteria rapidly convert it to nicotinic acid. Together with the Princeton isotope work, these findings establish that the main route from oral NR to increased NAD is through bacterial breakdown to nicotinic acid, followed by absorption and rebuilding via the Preiss-Handler pathway. This means that both NR and NMN are effectively pro-drugs for cheap nicotinic acid, not direct cellular NAD precursors as marketed.

A 2025 meta-analysis pooled 10 randomized controlled trials of NMN and NR in adults over 60—the population that should benefit most if the NAD-decline theory is correct. It found no significant improvements in skeletal muscle index, handgrip strength, gait speed, or chair stand tests. The authors concluded that despite positive preclinical findings, the effects are negligible. A separate meta-analysis on metabolic outcomes found no significant improvements in fasting glucose, insulin, HbA1c, cholesterol, or triglycerides, despite confirmed increases in blood NAD. To test whether NAD boosting might help under conditions of metabolic strain, researchers gave NR to about 60 long COVID patients for 20 weeks. Blood NAD tripled, but there was no difference between NR and placebo in fatigue, sleep quality, anxiety, or depression. The speaker argues that if NAD boosting were ever going to show a functional benefit, long COVID was the ideal test, and it failed. This body of evidence suggests that raising blood NAD is not a meaningful therapeutic strategy for age-related decline or illness.

The speaker cites a 2022 study showing that older adults who are exercise-trained maintain NAD levels in their muscles comparable to those of younger individuals. This implies that the age-related decline in NAD is not a fixed biological inevitability but can be modulated by physical activity. Combined with the lack of functional benefits from pharmacological NAD boosting, this finding reinforces the speaker's argument that exercise is a superior intervention for supporting NAD and overall longevity. It also undercuts the urgency to supplement with expensive precursors when a free, well-evidenced alternative exists.

The speaker states that he deliberately chose to include nicotinamide, a simple and inexpensive form of vitamin B3, in his product 'micro vitamin'. This decision is directly informed by the evidence that NR and NMN are broken down to nicotinic acid before affecting NAD, and that meeting baseline vitamin B3 requirements is sufficient. He contrasts this with the supplement industry's promotion of $60/month premium forms. This personal shift serves as a practical recommendation for listeners: rather than paying for expensive NAD precursors, one can use cheap nicotinamide or nicotinic acid and focus on exercise.