NMN and NMNH: Supporting NAD+ for Cellular Energy, Healthy Aging, and Longevity

Few molecules have generated as much excitement in the fields of longevity, metabolic health, and healthy aging as nicotinamide adenine dinucleotide (NAD+). Present in every living cell, NAD+ plays a critical role in cellular energy production, mitochondrial function, DNA repair, and cellular health and resilience (1,2,5).

Research suggests that NAD+ levels naturally decline with age. Age-related declines in NAD+ have been associated with:

• Mitochondrial dysfunction

• Impaired cellular communication

• Reduced energy production

• Diminished metabolic efficiency (1,2,5)

These changes have prompted significant scientific interest in strategies that may help support or restore healthy NAD+ levels throughout the lifespan.

Among the most extensively studied approaches are nicotinamide mononucleotide (NMN) and its reduced counterpart, NMNH. Both compounds have attracted significant scientific interest because of their relationship with NAD+ metabolism and their potential role in supporting cellular energy production, metabolic function, and healthy aging.

While NMN has become one of the most extensively studied NAD+ precursors in human clinical research, interest is rapidly growing around NMNH, the reduced form of NMN. Early laboratory and preclinical research suggest that NMNH may increase NAD+ levels more efficiently than NMN under certain conditions, potentially due to differences in how it is metabolized and utilized within cells. These findings have generated considerable excitement among researchers and healthcare practitioners and have helped position both compounds at the forefront of modern longevity research.

Understanding NMN and NMNH

NMN is a naturally occurring molecule produced within the body and found in small amounts in:

• Broccoli

• Avocado

• Cabbage

• Cucumber

• Edamame

As a direct precursor to NAD+, NMN helps provide the body with one of the building blocks required for NAD+ synthesis (1).

NMNH is the reduced form of NMN. Emerging research suggests that NMNH may increase NAD+ levels more efficiently than NMN in certain settings, making it an exciting area of ongoing research. Both compounds are designed to support the body's production of NAD+, a molecule essential for cellular energy production and healthy aging.

Why NAD+ Matters

NAD+ plays a critical role in helping cells convert nutrients into ATP, the body's primary source of energy. It also supports mitochondrial function, DNA repair, cellular communication, and healthy metabolic processes (1,2,5).

As NAD+ levels decline with age, blood vessels become less efficient at delivering oxygen and nutrients to tissues. Researchers have linked age related declines in NAD+ and SIRT1 activity to:

• Reduced blood flow

• Diminished muscle function

• Decreased endurance

• Many of the physical changes commonly associated with aging (6)

These findings help explain why maintaining healthy NAD+ levels has become an important focus of longevity research.

Because of NAD+'s central role in energy production and mitochondrial health, researchers are increasingly interested in strategies that support healthy NAD+ status throughout the lifespan (1,2,5).

What Does the Research Say?

One of the strongest findings in scientific literature is that oral NMN supplementation increases NAD+ levels in humans. A systematic review and meta-analysis published in 2025 evaluated 12 randomized controlled trials involving more than 500 participants and found that NMN supplementation significantly increased blood NAD+ levels compared with placebo (4). This confirms that orally consumed NMN is effectively absorbed and utilized by the body.

Human studies have reported potential improvements in:

• Energy production and cellular vitality

• Insulin sensitivity

• Physical performance

• Walking endurance

• Sleep quality

• Vascular function

• Muscle performance (1,3)

In animal studies, NMN supplementation restored blood vessel density, improved blood flow to muscle tissue, and significantly increased exercise capacity in older mice. These findings sparked significant scientific interest in the potential role of NMN in supporting healthy aging, energy production, vascular health, and physical performance (6).

Potential Clinical Applications

Current evidence suggests that NAD+ supporting compounds may be most relevant for individuals experiencing age related declines in metabolic or physical function (3,4).

Potential areas of interest include:

• Healthy aging and cellular vitality

• Energy production and mitochondrial function

• Metabolic health support

• Physical performance and endurance (1,3)

Safety and Tolerability

Among the most reassuring aspects of the current literature is the favorable safety profile observed with NMN.

Across multiple human clinical trials, NMN has generally been well tolerated with relatively few reported adverse effects (1,2,3). Researchers have evaluated daily doses ranging from 250 mg to 1,250 mg and have consistently reported favorable safety outcomes within those ranges (3,4).

At Crossroads Apothecary, we believe that healthy aging begins with supporting the body's foundational systems. If you are interested in learning whether NMN, NMNH, or other evidence based nutritional strategies may support your health goals, our team can help you explore a personalized approach to wellness, vitality, energy production, and healthy aging. Ask us about our NAD+ testing kit, which uses a simple finger prick collection to measure your NAD+ status. Testing can provide a valuable baseline before starting supplementation and helps track improvements over time, allowing you to monitor your progress and make more informed decisions about your health and longevity journey.

Dr. Kisha Henry DCN, MSN

References

1. Song Q, Zhou X, Xu K, Liu S, Zhu X, Yang J. The Safety and Antiaging Effects of Nicotinamide Mononucleotide in Human Clinical Trials: an Update. Adv Nutr. 2023;14(6):1416-1435.

2. Freeberg KA, Udovich CC, Martens CR, Seals DR, Craighead DH. Dietary Supplementation With NAD+ Boosting Compounds in Humans: Current Knowledge and Future Directions. J Gerontol A Biol Sci Med Sci. 2023;78(12):2435-2448.

3. Benjamin C, Crews R. Nicotinamide Mononucleotide Supplementation: Understanding Metabolic Variability and Clinical Implications. Metabolites. 2024;14(6):341.

4. Zhang J, Poon ETC, Wong SHS. Efficacy of Oral Nicotinamide Mononucleotide Supplementation on Glucose and Lipid Metabolism for Adults: a Systematic Review with Meta Analysis on Randomized Controlled Trials. Crit Rev Food Sci Nutr. 2025;65(22):4382-4400.

5. Bloomer RJ, Timmcke JQ, Ramanathan C. Use of the Dietary Supplements NR and NMN to Increase Nicotinamide Adenine Dinucleotide, Impact Mitochondrial Function, and Improve Metabolic Health. Clinical Bioenergetics. 2025;1(2):9.

6. Pesheva E. Rewinding the Clock. Harvard Medical School News. 2018 [cited 2026 Jun 16]. Available from: https://hms.harvard.edu/news/rewinding-clock.