- NR levels in humans do not increase after 3 weeks of 1,000 mg a day of oral NR supplements
- NR given to lactating mice does not reach the bloodstream
So how does NR supplementation work? NR increases levels of NAD+ in the blood.
According to Dr Brenner, the increased NAD+ in the blood made it’s way into the milk of nursing mothers, and that NAD+ provided the benefit to nursing pups.
It seems likely it is also the increased NAD+ in the blood that lowered the inflammation markers in humans, since NR is only found at trace levels in the blood, and doesn’t increase with supplementation.
These studies show NR supplementation resulted in increased levels of NAD+ in the bloodstream, but not NR.
NR supplements do not reach the bloodstream as NR.
- The liver blocks most NR (and NMN) supplements from circulating in blood
- NR is found at trace levels in the bloodstream
- NR supplementation does not increase levels of NR in the blood
- NAD+ is present at 100 – 300x higher quantites than NR
- NAD+ levels in the blood do increase with NR supplementation
The benefits noted from supplementation with NR in recent research are from increased NAD+ circulating in the bloodstream, not NR.
Sublingual NAD+ or NMN are likely much more efficient methods to increase NAD+ levels in the blood
https://alivebynature.com/nad-not-nr-is ... oodstream/