The compound nicotinamide mononucleotide (NMN) has gained interest for its ability to protect animals against metabolic degeneration and age-related illnesses. For these reasons, increasing number of clinical trials are in progress to confirm the solid benefits of NMN.
Klein and colleagues at Washington University School of Medicine in St. Louis published research in Science demonstrating for the first time that NMN improves prediabetic women’s muscle insulin sensitivity. They demonstrate that NMN achieves these beneficial metabolic benefits via improving insulin’s capacity to stimulate glucose uptake and activating genes involved in muscle structure and remodeling. However, the Missouri-based study team discovered that NMN had no effect on blood fat levels, blood sugar levels, or blood pressure. This Science article offers tantalizing evidence that NMN may aid in the prevention of age-related diseases.
NMN Increases NAD+ Levels in Human Blood Cells
NMN is a precursor of nicotinamide adenine dinucleotide (NAD+), a critical chemical for energy generation and metabolic function. Numerous studies have previously established that NMN promotes metabolic health in aged animals by raising NAD+ levels throughout the body.
Klein and colleagues evaluated the effects of consuming 250 mg capsules of NMN daily for ten weeks on prediabetic women aged 55 to 75 who were overweight. They discovered that NMN dramatically boosted NAD+ levels in blood cells, which are also critical components of the immune system, during the treatment course. While NMN therapy did not result in a rise in NAD+ levels in skeletal muscle, it did result in a substantial increase in NMN metabolic byproducts. This indicates that NMN was being converted to NAD+ and that the skeletal muscle was rapidly using the NAD+, preventing NAD+ levels from increasing.
NMN Enhances Muscle Metabolism and Repair in Humans
Klein and colleagues next examined the muscle’s sensitivity to insulin, a hormone that initiates the cellular absorption of carbohydrates, to observe how raising NAD+ levels with NMN affected metabolism. They observed that 10 weeks of NMN therapy increased muscle glucose consumption by roughly 25%. These data suggest that NMN improves muscle tissue sugar consumption. The NMN therapy boosted signaling for muscle metabolism and cell development. This was in line with recent results that NMN enhances insulin sensitivity and metabolism in muscle tissue while simultaneously stimulating muscle remodeling pathways.
NMN Boosts Muscle Remodeling Gene Activity
Klein and colleagues looked at gene activity patterns after NMN administration to establish that NMN enhances muscle metabolism. They discovered that NMN increases gene activity for “Platelet-derived growth factor” (PDGF), which governs muscle cell development and proliferation. These findings support NMN’s role in enhancing muscle metabolism, repair, and remodeling. These effects of NMN and if NMN therapy has similar effects in people with other illnesses or diseases are still unknown. Future research can see if NMN has similar benefits in other populations.
A similar study has demonstrated that another NAD+-boosting chemical, nicotinamide riboside (NR), has no effect on human muscle metabolism, at least in males. The mystery of why NMN has been demonstrated to boost muscle metabolism but NR has not remained unsolved. Klein and Imai are currently evaluating NMN in another experiment that will include both males and women.