Animal studies have shown promising results for NMN in restoring NAD+ levels and improving various aspects of health. Long-term supplementation in mice has been linked to suppressed age-related weight gain, enhanced energy metabolism, improved insulin sensitivity, and better muscle function. Research has also shown that NMN can influence gene expression related to aging, and in models of neurodegenerative conditions, it has helped protect neurons and improve cognitive function.

In humans, research is still in the early stages. A clinical trial in Japan tested NMN doses up to 500 mg in healthy men and found that NMN was well tolerated by the body without known negative effects. Some changes in biomarkers such as blood glucose and creatinine levels were observed, but they remained within normal ranges. Another trial focused on postmenopausal women found that NMN improved muscle insulin sensitivity, which can be an important marker of metabolic health, as enhanced insulin sensitivity helps the body better regulate blood sugar, supports energy metabolism, and reduces the risk of insulin resistance over time. Improved muscle insulin sensitivity is also linked to better nutrient absorption in muscle tissue, potentially leading to more sustained energy levels and improved physical performance.