Nicotinamide mononucleotide (NMN) has been touted as a promising supplement for improving cellular health and potentially extending lifespan. While animal studies have shown promising results, there is still much to learn about the effects of NMN supplementation in humans. In recent years, several human clinical studies have been conducted to investigate the safety and effectiveness of NMN supplementation.

One study, published in npj Aging and Mechanisms of Disease in 2016, investigated the effects of NMN supplementation on blood pressure and arterial health in middle-aged and older adults. The study included 60 participants, aged 40-60 years, who were randomized to receive either placebo or NMN supplementation for 12 weeks. The NMN group received a daily dose of 100 mg NMN powder, dissolved in water and taken orally.

The study found that NMN supplementation was safe and well-tolerated, with no serious adverse events reported. The NMN group also showed a significant reduction in systolic blood pressure compared to the placebo group. Additionally, the NMN group showed improvements in arterial stiffness, as measured by pulse wave velocity and augmentation index.

Another study, published in the journal Scientific Reports in 2019, investigated the effects of NMN supplementation on muscle metabolism and insulin sensitivity in older adults. The study included 24 participants, aged 55-79 years, who received either placebo or NMN supplementation for 6 weeks. The NMN group received a daily dose of 250 mg NMN capsules, taken orally.

The study found that NMN supplementation was safe and well-tolerated, with no serious adverse events reported. The NMN group also showed improvements in muscle mitochondrial function, as measured by ATP production rates. Additionally, the NMN group showed improvements in insulin sensitivity, as measured by the Matsuda index.

In terms of potential mechanisms of action, the study published in npj Aging and Mechanisms of Disease suggests that NMN supplementation may improve arterial health by increasing levels of a molecule called cyclic ADP-ribose (cADPR), which helps to regulate blood vessel tone and dilation. The study published in Scientific Reports suggests that NMN supplementation may improve muscle metabolism and insulin sensitivity by increasing levels of a molecule called nicotinamide adenine dinucleotide (NAD+), which is involved in many cellular processes.

As the study published in npj Aging and Mechanisms of Disease notes, "future clinical studies with larger sample sizes, longer durations, and broader clinical endpoints are needed to further validate the beneficial effects of NMN and its potential as a therapeutic agent for aging-related diseases." In the meantime, it is important to continue exploring the potential of NMN and other compounds for promoting healthy aging and improving overall health and well-being.

Reference:

Tsubota, K. (2016). The first human clinical study for NMN has started in Japan. npj Aging and Mechanisms of Disease, 2(1), 1-1.

Yoshino, J., Baur, J. A., & Imai, S. I. (2018). NAD+ intermediates: the biology and therapeutic potential of NMN and NR. Cell metabolism, 27(3), 513-528.