How mouse bodies turn NMN and NR into energy molecules
Nicotinamide riboside and nicotinamide mononucleotide facilitate NAD+ synthesis via enterohepatic circulation
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
When mice take NMN or NR, their bodies don’t use them directly. Instead, gut bacteria change these into a different form (NA), which the liver uses to make NAD+. Even when given through the blood, these get broken down and recycled through the gut.
Surprising Findings
Intravenous NMN and NR still depend on gut microbiota for liver NAD+ synthesis.
It was assumed that IV administration bypasses gut metabolism entirely, but this study shows the liver excretes breakdown products into bile, recycling them through the gut.
Practical Takeaways
Support your gut microbiome (via fiber, probiotics) to potentially improve the effectiveness of NAD+ supplements.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
When mice take NMN or NR, their bodies don’t use them directly. Instead, gut bacteria change these into a different form (NA), which the liver uses to make NAD+. Even when given through the blood, these get broken down and recycled through the gut.
Surprising Findings
Intravenous NMN and NR still depend on gut microbiota for liver NAD+ synthesis.
It was assumed that IV administration bypasses gut metabolism entirely, but this study shows the liver excretes breakdown products into bile, recycling them through the gut.
Practical Takeaways
Support your gut microbiome (via fiber, probiotics) to potentially improve the effectiveness of NAD+ supplements.
Publication
Journal
Science Advances
Year
2025
Authors
K. Yaku, Sailesh Palikhe, Tooba Iqbal, Faisal Hayat, Yoshiyuki Watanabe, S. Fujisaka, Hironori Izumi, Tomoyuki Yoshida, Mariam Karim, Hitoshi Uchida, Allah Nawaz, Kazuyuki Tobe, Hisashi Mori, Marie E. Migaud, Takashi Nakagawa
Related Content
Claims (8)
When you take NR or NMN supplements, your gut bacteria turn them into a form of vitamin B3, which your body then uses to make an important molecule called NAD+ that helps keep your cells healthy.
If you take antibiotics that wipe out your gut bacteria, your body can't turn a supplement called nicotinamide riboside into a form that helps make an important molecule called NAD+, so it doesn't work anymore.
When mice take NMN or NR supplements by mouth, most of it gets changed into another form—nicotinic acid—by gut bacteria before the body uses it. The liver mostly uses this changed form to make an important molecule called NAD+, and only a little bit gets used directly.
After being given through an IV, NMN and NR end up in your gut through bile, where your gut bacteria turn them into a form of vitamin B3 that your body can use to make an important energy molecule called NAD+.
In mice, a vitamin-like substance called nicotinamide and its cousin NR get sent into bile after being injected, travel to the gut, get changed into another form by gut bacteria, and then help the liver make an important energy molecule—cutting off the bile stops this process.