Nicotinamide riboside and NMN raised NAD by the same amount
When 65 healthy adults took one or the other for 14 days, circulating NAD rose about equally. Plain nicotinamide, the cheap B3 already in food, did nothing.
What the study found
Head to head, neither precursor beat the other
The marketing on both sides says one is better absorbed. When 65 healthy adults took nicotinamide riboside or nicotinamide mononucleotide for fourteen days, circulating nicotinamide adenine dinucleotide rose about equally. Plain nicotinamide, the cheap B3 in food, did nothing.
The caveat · Absorption compared, not benefit
Fourteen days and open-label, so the comparison is of absorption, not of benefit, and neither arm measured anything a person would feel. Nine of the twelve authors work for Nestle, whose health science arm sells NAD-related products, which is worth noting mainly because the result cuts against both branded products rather than favouring either.