Of all the studied areas, I think the potential benefits of NAD on muscle function was discussed first. NR and NMN dietary supplements have been used in the fitness and exercise industries for years. The goal was to increase NAD+ levels in your skeletal muscles and help protect the muscles and bones from age-related metabolic issues.
Here, we have more human studies.
What do we see?
- NR was given in the amount of 1 g per day for 21 days to 12 men in a double blind-controlled randomized crossover trial. Mitochondrial bioenergetics and skeletal muscle NAD metabolism were stimulated. Serum inflammatory cytokines were reduced.
- Another randomized double-blind controlled crossover study was performed in 13 healthy obese humans. NR given in the amount of 1 g daily for 6 weeks caused some small changes in body composition and sleeping metabolic rate, increased NAD levels, and altered skeletal muscles.
- Another study in humans showed oral NAD with NR or NMN does NOT alter muscle response to endurance exercise. One week of NR given in 1 g/day for 8 young men did not influence skeletal muscle mitochondrial respiration or acetylation.
- Another randomized controlled trial test in home aerobic and exercise training after 16 weeks of NR showed improved muscle mass and fitness in adolescent and young adult survivors of stem cell transplants.
- In a rat study, chronic NR supplementation in swimming rats had decreased exercise/swimming performance.
- NAD used in experiments is shown to improve mitochondrial activity and muscle stem cell function, as well as enhance life span in aged muscle.
- In an experimental model of muscular dystrophy, NR prevented cell senescence.
- Possibly a therapy for rheumatoid arthritis patients, NR and NMN we ex vivo tested (not in people) showed a reduction in the inflammation and oxidative issues in RA patients.
- Experiments showed NR affected the development and growth of the pec major muscle when injected into the yok of developing eggs, as shown by an increase in muscle weight, length, and fiber density.
So what do these studies show us?
All of these studies listed are either “experimental” in the lab or are conducted in super small numbers. Studies of 8, 16, and even 30 are too small.
A few of these studies did not show an improvement in endurance or performance; however, most show improvement. You will see the way of administering NR, the amounts, and the duration of treatment are all over the place. It may be in the study of the young men that when NAD levels are still high enough, supplementation is a waste of money. It may be something that we need to start treating when it starts to wane.
Again, this is emerging science. There is something here. We just need to get to the root of how to optimize it.
