Key Points
- NMN was absorbed within minutes
- Insulin sensitivity and fat cell profiles improved
- Age-related weight gain was suppressed
- NMN improved eye function and bone density
- Mice showed increased energy use
Methods
The study ran in mice beginning at 5 months of age to observe the effects of NMN supplementation during normal aging. Mice were divided into three groups:
- Control Group: Standard food + regular drinking water daily for 12 months
- NMN 100 Group: Standard food + 100 mg/kg NMN in drinking water daily for 12 months
- NMN 300 Group: Standard food + 300 mg/kg NMN in drinking water daily for 12 months
NMN Was Rapidly Absorbed to Make NAD+
NMN levels rapidly increased within minutes of oral administration, implicating fast absorption in the gut.
NMN entered circulation within minutes and was quickly converted into NAD⁺ in energetically active tissues such as liver and skeletal muscle.
"Hepatic NAD+ levels showed a steady increase from 15 to 30 min."
Through tracing, researchers confirmed the NMN directly synthesized into new NAD⁺.
"NMN is quickly absorbed, efficiently transported into blood circulation, and immediately converted to NAD+ in major metabolic tissues."
Cellular transport and NAD⁺ recycling efficiency determine how effectively NMN can replenish declining NAD⁺ pools in aging tissues.
Energy Levels & Physical Activity Increased
Compared to controls, NMN-treated mice showed:
- Higher oxygen consumption
- Higher energy expenditure
- Greater reliance on fat usage
- Preservation of metabolic rates typically lost with aging
Lower doses appeared more favorable for maintaining physical activity, suggesting dose-dependent effects.
"Mice treated with NMN for 12 months were able to maintain both oxygen consumption and energy expenditure close to those of control mice."
Metabolic Health Profile Improved
In the NMN groups, researchers noted preventative effects against age-associated declines in metabolic processes.
After one year:
- Insulin sensitivity was significantly better in NMN-treated mice
- Liver fat cell accumulation was reduced
- Circulating free fatty acids rose less with age
"The 300 mg/kg/day NMN-administered group tended to show lower fasted insulin levels after 3 to 9 months of treatment."
This graph shows the NMN 300 mg/kg/day group (blue) had the greatest drop in blood glucose after insulin injection, suggesting improved insulin sensitivity compared to the NMN 100 mg/kg/day group (green) and the control group (red).
Genes related to aging in key metabolic tissues showed reduced activity.
"76.3%, 73.1%, and 41.7% of the genes changed in skeletal muscle, WAT, and the liver of control mice, respectively, were not significantly altered in NMN-administered mice."
The muscle cells were better at producing energy, meaning their "cellular power plants" (mitochondria) were working more efficiently.
"Skeletal muscle exhibited the most profound preventive effects of NMN…showed significant enhancement of the maximum respiration rate induced."
In addition, communication between the cell's control center (the nucleus) and the mitochondria improved. Mitochondrial efficiency directly influences energy production and the pace of age-related functional decline.
Aging-Related Symptoms Declined
Long-term NMN was found to significantly improve:
- Eye Function: Retinal responses were preserved and tear production increased
- Bone Density: A notable increase in bone density was observed
- Immune Cell Balance: Immune cell balance also shifted in a direction associated with healthier aging
- Weight Gain: NMN-treated mice gained less weight as they aged, even though they ate and drank more than control mice
"NMN brings significant anti-aging effects on a variety of age-associated pathophysiological changes."
Conclusion
This long-term study shows that sustained NMN supplementation can help support age-related functional declines in mice.
"NMN suppressed age-associated body weight gain, enhanced energy metabolism, promoted physical activity, improved insulin sensitivity and plasma lipid profile, and ameliorated eye function and other pathophysiologies."
These findings further support the idea that NAD+ availability plays a central role in metabolic health and age-related decline.
"Enhancing NAD+ biosynthesis by using NAD+ intermediates, such as NMN and NR, is expected to be able to ameliorate such age-associated physiological decline effectively."
While these results come from an animal model, they provide a strong mechanistic rationale for continued human research into NAD⁺ precursors and healthy aging.
