Can NMN or NR restore NAD+ and slow aging?

Background

NAD+ levels fall with age in many tissues, and raising them extends healthspan in some animal studies. Supplements such as nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR) are marketed to reverse this decline.

What the human research shows

• Human trials consistently show NMN and NR can raise NAD+ levels in blood.
• Effects on clinical outcomes in people, such as muscle function, insulin sensitivity or blood pressure, have been small or inconsistent across trials.
• Most trials are small, short and enroll fewer than about 100 people.

What we still don’t know

• Whether raising blood NAD+ changes NAD+ in key tissues in a meaningful way.
• Whether any benefit appears over years rather than weeks.
• Long-term safety at higher doses.

Safety and status

Generally well tolerated in short trials. NMN’s regulatory status as a supplement in the U.S. has been disputed, and product quality varies.

Sources

1. Reiten et al. Preclinical and clinical evidence of NAD+ precursors in health, disease, and ageing. Mechanisms of Ageing and Development, 2021
2. VALREXA profile: NAD+

Last reviewed November 7, 2026. Educational only; not medical advice, and not a recommendation to take any drug or supplement. Talk to a clinician before starting anything.