What the research shows
Grant and colleagues followed NAD+ and several breakdown products in blood plasma and urine during a six-hour human pilot study. Plasma NAD+ showed no measurable rise during the first two hours. At six hours, the researchers found increased urinary excretion of NAD+ and methylnicotinamide. The study tracked where these chemicals appeared. It did not test whether participants felt better or lived longer. Read the human plasma and urine study.
Documented formats
The investigators studied a solution containing NAD+ itself. Studies that give participants a precursor such as nicotinamide riboside begin with a different molecule, even when both studies later measure NAD+.
Testing and purity
Check whether a method reports oxidized NAD+, reduced NADH or their combined total. Record the sample type as well. A urine measurement and a muscle measurement answer different questions.
How to read a batch reportQuestions about NAD+
Can a plasma measurement tell us how much NAD+ entered muscle?
Plasma is the liquid part of blood. To quantify NAD+ in muscle, investigators would need a tissue measurement or another method validated for that purpose.
What does a rise in urinary NAD+ show?
It shows that the amount leaving the body in urine rose over the sampling interval. It does not directly measure how a particular organ used it.