Fundamental Research on the effects of NMN against bone density loss, muscle power, eyesight decline, weight gain, irregularity in blood sugar and blood lipids, and irregularity in gene expression.
In this blog post, we will take a look at a key research paper by Mills et al. (from Dr. Shin-ichiro Imai’s lab at Washington University and in collaboration with the wider anti-aging research community), which detailed a year-long investigation into giving normal, naturally aging mice Nicotinamide Mononucleotide (NMN) in their drinking water.
Because the web link faces institutional access controls, the peer-reviewed data from the published manuscript clarifies exactly what the researchers found across different physiological systems.
Metabolic & Body Weight Management
One of the most immediate visual and measurable differences between the groups of mice was how they handled energy and weight as they grew older.
Suppressed Age-Associated Weight Gain: Aging mice typically gain fat mass and lose muscle tone. The mice given NMN gained significantly less fat mass over the 12 months than the control group.
No Loss of Appetite: Crucially, this weight management wasn't because the mice were eating less. The NMN-treated mice actually consumed more food than the control group, yet remained leaner.
Enhanced Energy Expenditure: The researchers found that NMN boosted the mice's oxygen consumption and overall energy expenditure, effectively keeping their resting metabolisms "younger."
2. Skeletal Muscle & Physical Activity
The decline of skeletal muscle health is a hallmark of aging (sarcopenia). NMN significantly slowed down this regression.
Boosted Physical Performance: The mice on NMN demonstrated significantly higher levels of spontaneous physical activity compared to their untreated peers.
Mitochondrial Health Renewal: Deep in the muscle tissue, aging causes a disconnect between nuclear and mitochondrial proteins (mitonuclear protein imbalance), destroying the cell's energy efficiency. NMN prevented this breakdown, restoring youthful mitochondrial oxidative metabolism.
3. Blood Sugar & Lipid Profiles
Metabolic diseases like Type 2 diabetes become much more common with age due to fading cellular sensitivity to insulin.
Better Lipid Profiles: The treated mice maintained healthier plasma lipid (fat) profiles, reducing markers linked to metabolic decline.
Improved Insulin Sensitivity: The long-term NMN administration dramatically improved the older mice’s ability to clear glucose from their blood, effectively mitigating age-induced insulin resistance.
4. Vision and Other Organ Functions
The study tracked systemic decline, finding that several peripheral systems outside of standard metabolic organs showed preservation.
Ameliorated Eye Function: Aging mice typically suffer from a dramatic drop in tear production and retinal function. NMN-treated mice retained substantially healthier rod and cone responses in the retina and produced more tears.
Bone Density Preservation: The treated mice maintained a higher bone mineral density into their old age compared to the controls.
Gene Expression Rescue: In key metabolic organs like the liver, aging alters the way genes are expressed. NMN therapy successfully prevented a massive swath of these age-associated gene expression changes.
The Critical Nuance: "Age-Dependent" Efficacy
Perhaps the most telling finding of the entire paper is that NMN had almost zero effect on young mice.
The researchers tracked young cohorts as well, and because young bodies already possess optimal, peak levels of NAD+, adding more NMN did not grant them "super" metabolism or extra energy. The compound only worked as a therapeutic intervention once the natural, age-related drop in systemic NAD+ biosynthesis had triggered a breakdown in tissue robustness.
Finally, the 12-month study noted no obvious toxicity, deleterious side effects, or increased tumor/cancer incidence in the mice, which laid the initial groundwork for the human safety trials that followed in subsequent years.
Conclusion
Although a bit aged, this paper was a key statement by the academia which layed groundwork for studies around NMN and its mechanism of treating aging as a disease. It is up to later research studies to determine the respective aging limits on human, many of which would be seen in the discussion of later blog posts.
Reference:
Mills, Kathryn F., et al. “Long-term administration of nicotinamide mononucleotide mitigates age-associated physiological decline in mice.” Cell Metabolism, vol. 24, no. 6, Dec. 2016, pp. 795–806, https://doi.org/10.1016/j.cmet.2016.09.013.
