The NAD rise may be your gut bacteria's work, not the pill's
Fourteen days of nicotinamide riboside and of NMN raised NAD about equally, but added straight to blood neither did anything. The authors trace the rise to gut bacteria.
What the study found
The boost may come from gut bacteria, not from the molecules
In the first head-to-head human trial, fourteen days of nicotinamide riboside or nicotinamide mononucleotide raised circulating nicotinamide adenine dinucleotide about equally; plain nicotinamide did not. Neither worked added straight to blood: the authors trace the rise to gut bacteria.
The caveat · Gut step seen in lab vessels only
Open-label, fourteen days, healthy adults, so this establishes a route rather than an outcome. The bacterial step was shown in fermentation vessels seeded with human gut microbes rather than watched in the participants themselves. Nine of the twelve authors work for Nestle, whose health science arm sells NAD-related products.