A Pilot Study Investigating Changes in the Human Plasma and Urine NAD+ Metabolome During a 6 Hour Intravenous Infusion of NAD.
Level 4 - case-series / case-control
Uncontrolled human pilot pharmacokinetic study
PubMed 31572171 · doi:10.3389/fnagi.2019.00257
What was done
Human participants received a 6-hour intravenous infusion of NAD+ at a rate of 3 µmol/min. Plasma and urine levels of NAD+ and related metabolites (nicotinamide, methylnicotinamide, adenosine phosphoribose ribose [ADPR], and nicotinamide mononucleotide [NMN]) were monitored during and after the infusion.
What was found
No changes were observed in plasma concentrations of NAD+ or its measured metabolites (nicotinamide, methylnicotinamide, ADPR, and NMN) until after the first 2 hours of infusion. At 6 hours, urinary excretion of both intact NAD+ and methylnicotinamide increased, while urinary nicotinamide showed no significant rise. The abstract reports no numerical values, concentrations, or variance metrics.
Why it matters
This study provides initial human pharmacokinetic data on directly infused NAD+, demonstrating that exogenous NAD+ is rapidly cleared from the bloodstream in the initial hours of infusion, likely via tissue uptake or enzymatic degradation.
Limits
The abstract does not state the sample size (n), baseline participant characteristics, or safety and clinical outcomes. The study lacked a control or comparator arm, and no quantitative values, effect sizes, or statistical bounds are provided in the text.
Cited by
- context Direct oral ingestion of pure NAD+ has poor cellular bioavailability compared to oral precursor supplementation or intravenous NAD+ infusion.