A 90-day randomized, double-blind, placebo-controlled phase I trial in 80 healthy adults aged 40–65 tested oral NMNH-Ca at 125, 250, and 500 mg daily. Whole-blood NAD rose dose-dependently: +8.22, +15.85, and +39.90 µM versus +2.33 µM for placebo at day 90. Acute pharmacokinetics showed peak NAD at 12 hours post-dose. No serious adverse events, treatment-related adverse events, or discontinuations occurred at any dose. Exploratory signals favored 500 mg for blood phenotypic age, six-minute walk distance, and SF-36 quality-of-life scores.
NMNH (dihydro-NMN) represents a structurally distinct NAD precursor from the now-crowded NMN/NR field. Preclinical data suggested NMNH raises NAD more rapidly and robustly than oxidized NMN, and this trial offers the first controlled human dose-response data. The 39.9 µM absolute NAD rise at 500 mg is noteworthy — comparable to or exceeding gains reported with standard NMN in similar trials — though cross-trial comparisons are hazardous given differing measurement methods. Critical limitations abound: 80 participants is small, 90 days is short for geroscience endpoints, and whole-blood NAD may not reflect tissue-level changes most relevant to aging biology. The exploratory efficacy signals — phenotypic age, walk distance — are hypothesis-generating only, not powered for inference. As a preprint posted on medRxiv and not yet peer-reviewed, these findings could change substantially after expert scrutiny. Overall, an incremental but credible safety and pharmacodynamic step forward that appropriately calls for larger, longer confirmatory trials.
