NMN is safe and can improve physical function and metabolism in the elderly.
1. Throughout the NMN human trials, the precursor of the substance did not cause any adverse physiological effects, thus confirming its safety.
2. Human trials have shown that NMN is good for improving the insulin sensitivity of adults and improving their physical abilities.
As levels of NAD+ decline with age, the researchers hypothesized that increasing levels of precursors like NMN could protect adults from age-related organ degeneration. As a result, a large number of people have started replenishing NMN, which is expected to boost the global NMN market in the coming years from USD 252.7 million in 2020 to an estimated USD 385.7 million by 2027.
The first study to evaluate the safety of NMN, a 2016 Keisei University, Japan, short-term study included male participants taking 100, 250, or 500 mg of NMN in the morning. The researchers monitored them for the next five hours. The results of the study showed no harmful effects or changes in blood pressure, heart rate, oxygen saturation, or body temperature. Based on their findings, researchers at Keil University concluded that up to 500 mg of NMN is safe and well tolerated.
Since the 2016 CAEU study, seven additional human trials at different doses have been conducted, testing safety parameters. The highest oral dose of NMN was in a Harvard study at 1,000 mg per day for 14 days with no adverse side effects. These studies show that NMN is safe and acceptable.
Among other physiological parameters, studies on the anti-aging effects of NMN have given some positive results related to physical performance, brain function and metabolism. The researchers recently expanded human trials in rodents to test whether NMN can improve age-related physical decline. Along these lines, Igarashi and colleagues found that over a 30-second period, NMN improved older adults' muscle movement, walking speed, left hand grip strength, and frequency of standing and sitting in a chair. Data from this study suggest that NMN improves physical performance in older adults.
Another study measuring the effects of NMN on physical performance comes from Liao and colleagues. Measuring its effects, NMN significantly improved runners' aerobic capacity, as measured by oxygen consumption in the blood, which is the amount of oxygen used by the body for energy production. Separately, a study by Huang and colleagues showed that NMN promoted sustained improvements in walking endurance during a 6-minute walking endurance test in adults aged 40 to 65 years. These results suggest that NMN can improve exercise capacity in middle-aged and older adults.
A study noted the benefits of NMN for diabetes prevention in postmenopausal overweight or obese women. Along with improved insulin signaling, NMN increased participants' muscle insulin sensitivity by about 25 percent, according to the findings. These results suggest that NMN has metabolic benefits, especially in prediabetic women.
More evidence from human trials shows that NMN can improve age-related hearing loss. Following this, Igarashi and his colleagues found enhanced hearing function in the right ear of older men. These findings suggest that NMN can restore hearing in older adults.
The ends of chromosomes (telomeres) shorten with age, and this shortening is a biomarker of aging. Niu and his colleagues found that after 90 days of treatment in men aged 40 to 60, blood cells (peripheral blood mononuclear cells) supplemented with 300 mg of NMN per day nearly doubled in telomere length. These results indicate that NMN supplementation has anti-aging effects at the molecular level.
Human trial results show that NMN is safe and has beneficial effects on body function, insulin sensitivity, telomere length, and possibly hearing during aging.
Some rodent studies have shown that NMN improves brain, respiratory, liver, heart, immune and reproductive function, but whether these benefits translate to humans remains to be determined. Essentially, more trials in humans are needed to determine whether NMN provides the same benefits to humans as it does to rodents.
Human trials of NMN have shown that the NAD+ precursor NMN can improve body function, metabolism, telomere length and possibly hearing ability during aging. Research to date also shows that using NMN is safe.