What Do We Know About NMN in Humans? A Summary of NMN Clinical Studies

There has been a growing interest in understanding the effect of NMN supplementation on metabolism, aging, and lifespan. And the past year has seen several clinical studies examining the safety and effect of NMN in people.

Here’s a summary of all the NMN human studies that have come out since 2021.

NMN Studies in 2021

In April 2021, a group at the University of Washington published the world's first clinical research paper using NMN, an NAD+ precursor, in Science. Here, obese and borderline diabetic postmenopausal women received a placebo or NMN (250 mg/day) for ten weeks. No adverse events were observed, and the NMN group showed increased skeletal muscle insulin sensitivity, insulin signaling, and muscle remodeling.

In June last year, a clinical study of NMM on amateur runners was reported from the Guangzhou Sports University in China. The study compared NMN at baseline and after six weeks of intervention between a placebo group and four groups divided into three doses—300, 600, and 1200 mg—of NMN daily. 

There were no changes in body composition or cardiac function indices such as body fat mass, body fat percentage, or BMI regardless of NMN dose, but there was a dose-dependent increase in skeletal muscle oxygen utilization in the medium- and high- dose groups. No adverse events were observed in the high-dose group. These results suggest that muscle is one of the tissues most sensitive to NMN and that exercise training with NMN supplementation may be an exercise strategy to improve endurance in athletes. 

NMN Studies in 2022

In a clinical study at the University of Tsukuba published in January 2022, 108 elderly subjects were divided into four groups (NMN morning intake and afternoon intake; placebo morning and afternoon intake). The researchers examined the effects of NMN 250 mg/day for 12 weeks on sleep quality, fatigue, and physical performance. In particular, the NMN afternoon intake group showed the greatest improvement in lower limb motor function and sleepiness. These findings suggest that afternoon NMN intake may be more effective in improving lower limb function and reducing sleepiness in the elderly and may be beneficial for mental and physical health.

In April 2022, researchers from the University of Toyama in Japan showed that healthy volunteers who received 250 mg/day of NMN for 12 weeks caused no abnormalities in physiological and laboratory tests and no obvious adverse effects. NAD+ levels in whole blood were significantly increased after NMN administration. They also found that the increased amount of NAD+ was strongly correlated with pulse rate before the administration of NMN. These results suggest that oral administration of NMN is a safe and practical strategy to boost NAD+ levels in humans.

A month later, research from Effepharm, a company out of Shanghai, China, came out with clinical results from 66 healthy subjects between the ages of 40 and 65 who took two capsules containing 150 mg of NMN daily after breakfast for 60 days. The study reported results suggesting a rise in the levels of available NAD+ at day 30 and day 60, which they suggest illustrated the potential of NMN to raise the levels of NAD+ in humans. Also, there were claims that there were improvements in energy levels and an anti-aging effect related to insulin sensitivity—the ability of cells of the body to use blood glucose more effectively.

NMN Has Positive Effects on Aging Markers in Adults

The latest findings come from a new clinical trial out of Japan. This June 2022 study shows that postmenopausal women who consumed NMN 300 mg/day orally for eight weeks showed no safety issues. Plus, Morita and colleagues show that may NMN supplementation led to favorable changes in various biomarkers (i.e., blood biochemistry, glucose metabolism, lipid metabolism, hormones, and immunity) measured as clinical tests.

This study adds to the growing research suggesting that NMN may be a promising nutritional material for human aging and metabolic control. “The positive changes in various biomarkers observed with oral intake of NMN suggest that NMN may be a promising nutritional material with the potential to control aging and extend healthy life expectancy,” wrote the authors.

In this study, there was a decrease in Hemoglobin A1C (HbA1c), which—via a simple blood test that measures your average blood sugar levels over the past three months—indicates better sugar metabolism. Glycation, a reaction between reducing sugars such as glucose and fructose and proteins under non-enzymatic conditions, produces terminal glycation products (AGEs) via HbA1c and other intermediates, resulting in qualitative and functional degradation of proteins in the body. In this clinical study, glycation also significantly decreased.

NMN also affected fatty acid (lipid) metabolism. While LDL-C—the so-called “bad cholesterol”—values were unchanged, the levels of HDL-C, which helps rid your body of excess cholesterol, so it's less likely to end up in your arteries, increased. The improved HDL-C levels reflect a positive effect of NMN administration on lipid metabolism, which is consistent with previous reports of improved glucose and lipid metabolism.

Conclusion and Currently Active NMN Studies

Together, these studies show that the effects of NMN treatment impact exercise capacity, sleep, and fatigue. Importantly, they provide some insight into the necessary dosing strategies to have an effect while maintaining safety. 

There are a few clinical trials studying NMN in a context that relates to aging:

• Effect of NMN on Muscle Recovery and Physical Capacity in Healthy Volunteers With Moderate Physical Activity
• Effect of NMN Supplementation on Organ System Biology
• Safety and Pharmacokinetics of Nicotinamide Mononucleotide (NMN) in Healthy Adults

These clinical trials will help to increase our understanding of NMN’s safety profile in adults and how it affects the levels of NAD+ as well as muscle and metabolic health.