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Photo of site author, Shelly Albaum

Shelly Albaum

Editor, Science of NAD

Important Disclosures

1. This is my personal website

All opinions are my own. Nobody writes here but me.

2. Supplements Are Not Medicines

Health Supplements like nicotinamide riboside are not intended to cure or treat any disease, condition, or illness.

3. No Medical Advice

I am a lawyer and a journalist, not a doctor, and I offer no medical advice. But I do follow the science, and I can bring to your attention

some interesting studies. You can read more about me here. And check with your physician -- your physician can look at this research, too.

4. Commercial Affiliations

I am a ChromaDex shareholder, and a marketing affiliate for Amazon and Rakuten. As a result, I will sometimes mention or recommend products that I endorse, like Tru Niagen, which I take every day. I may earn a small commission from qualifying purchases if you were referred directly from this site and completed a purchase. [Thank you!] You can read more about our advertising, privacy, and data collection policies here

Does NMN mostly deliver NR to cells?

Yes. The science is very clear that NMN works by turning into NR outside cells...

Which is better - NMN or NR?

Here are how scientists describe this problem:

NMN dephosphorylation to NR constitutes a critical step in order to act as an exogenous NAD+ precursor ...These data...provide compelling evidence for the extracellular conversion of NMN to NR...
--Nature Communications, October 11, 2016

We also showed that extracellular cleavage of NAD+ and NMN to NR is a prerequisite for using these nucleotides to maintain intracellular NAD contents….The degradation of NAD+ and NMN to NR or Nam is essential for these nucleotides to act as extracellular precursors of intracellular NAD.
-- Metabolites, November 29, 2019

These observations strongly support the conclusion that both NAD+ and NMN need to be degraded to NR outside the cell to serve as precursors of intracellular NAD+
-- Journal of Biological Chemistry, June 17, 2011

A study using stable isotope-labeled NR and NMN revealed that NMN is dephosphorylated into NR extracellularly. These results suggest that NMN is incorporated into cells after extracellular conversion to NR.
-- Journal of Biomedical Science, May 11, 2019

But all hope is not loss for NMN. It still works, because there are enzymes circulating in your body that break NMN into smaller pieces so that it can enter cells. Those smaller pieces are NR and Nicotinamide (NAM).

So that's mostly why and how NMN works -- it is a reliable way of delivering NR and/or NAM to your cells.

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