NAD+

What the research on NAD+ has looked at

• NAD+ and age in human tissue: the amount in human tissue falls with age. In skin samples from 49 people, from newborn to 77 years old, levels dropped as age rose. The pattern was clearer in males than in females
• NAD+ given directly: the one human study of the molecule itself found it left the blood almost at once. For the first two hours, neither it nor any of its breakdown products could be measured
• Nicotinamide riboside and blood levels: the building block nicotinamide riboside did raise blood levels, and the rise was dose-dependent. The 2.7-fold figure quoted almost everywhere came from a single person
• Nicotinamide riboside in older men: in 12 older men, three weeks of that building block lowered inflammatory signals in the blood. The energy machinery inside their muscle was unchanged. In 40 men over twelve weeks it changed neither insulin sensitivity, nor fat burning, nor body composition
• Nicotinamide mononucleotide and a disputed trial: in 25 women, ten weeks of the other building block improved how muscle responded to insulin. A researcher then objected in print that the two groups were not comparable to begin with. The authors published a reply