The longevity conversation often starts with NAD+. But understanding what it actually does is far more important than following the latest trend. The science behind healthy aging starts at the cellular level, and NAD+ and NMN are part of that story.
Cut through the NAD+ and NMN hype with a deep dive into how they really work, why declining levels impact your health, and what to do about it.
Plus, supplements that support healthy NAD+, NMN, and NADH levels that are essential for longevity.*
Why NAD+ Levels Decline—and Why It Matters
NAD+ (nicotinamide adenine dinucleotide) is an essential coenzyme found in all living cells. It’s required for a wide range of biological processes that support cellular function.1
NAD+ acts as a central regulator of cellular metabolism by enabling cells to convert nutrients into usable energy, regulate gene expression, and coordinate critical signaling pathways.1 NAD+ continuously cycles between its oxidized (NAD+) and reduced (NADH) forms, allowing it to support these functions across diverse tissues and cell types.2
Scientific research shows that NAD+ levels decline with age, and this decline has been observed in the liver, skin, brain, plasma, and skeletal muscle.3 Aging negatively affects NAD+ synthesis, and dietary patterns such as high-fat and high-protein diets further impair the body’s ability to maintain healthy NAD+ levels, contributing to reduced cellular efficiency over time. A high protein fat loss diet can actually work against your NAD+ status if not properly balanced.4
NAD+ Is Involved in 6 Key Biological Processes
Aging
Aging is the progressive, time-dependent accumulation of molecular and cellular damage that leads to declining physiological function. Aging is a reflection of deteriorating cell, tissue, and organ health. Age-related NAD+ decline has been observed in the liver, skin, brain, plasma, and skeletal muscle.3
DNA Repair
Efficient DNA repair is fundamental to cell health. NAD+ is a key regulator of DNA repair mechanisms including base excision repair and homologous recombination. As we age, telomere shortening and accumulated DNA damage become more pronounced. Research shows NAD+ availability directly influences DNA repair mechanisms.2
Energy Metabolism
Energy metabolism is how cells convert nutrients to energy (ATP). Optimal energy metabolism is essential to cell health. NAD+ plays a role in energy metabolism.* It’s reduced to NADH as part of the citric acid cycle, helping to generate ATP.7
Cell Death
Cell death occurs through regulated pathways like apoptosis, autophagy, and necrosis due to loss of cellular function or structural integrity. Properly regulated cell death is essential to cell and tissue health.8
Mitochondrial Function
Mitochondrial function includes many roles including ATP production. Mitochondria serve as the central hub of the cellular energy supply. NAD+ facilitates mitochondrial function via the SIRTs-PPARGC1A axis. Mitochondrial function is directly tied to cellular energy output and overall vitality.*9
Calcium Homeostasis
Calcium homeostasis is the tightly regulated maintenance of intracellular and extracellular calcium ion concentrations. The precise control of calcium concentration is critical to cell health because calcium serves as a universal second messenger for many cellular processes. NAD+ is involved in calcium homeostasis in neurons.*10
Three Ways to Support NAD+ Levels
When it comes to supporting NAD+ levels, three supplements lead the conversation: NMN, NADH, and NAD+. Each works differently, but all are designed to support the NAD+ system that supports healthy cellular function.*
NMN — The Direct NAD+ Precursor
Nicotinamide mononucleotide (NMN) is an intermediary metabolite in the NAD+ biosynthesis salvage pathway—the most efficient and main route for NAD+ production. Administration of NMN supplements has been shown to increase NAD+ levels.11
NADH — The Cellular Energy Partner*
NADH is the reduced form of NAD+. NADH feeds electrons into the cell's energy pathways, targeting ATP for efficient cellular energy support.*7
Together, NAD+ and NADH work in tandem. NAD+ accepts electrons during glycolysis and the citric acid cycle, while NADH delivers those electrons to the electron transport chain to generate ATP.2
Liposomal NAD+. A Breakthrough in Bioavailability
Traditional oral NAD+ supplements have low bioavailability due to NAD+'s large molecular size and poor membrane permeability.
Solaray Liposomal NAD+ is part of a new generation of supplements that provide excellent cellular energy support and utilize liposomal technology designed for optimal absorption.*
Can NAD+, NMN, and NADH Supplements Be Taken Together?
Supporting healthy NAD+ levels isn't a one-size-fits-all solution. NMN, NADH, and Liposomal NAD+ each bring something different to a longevity routine, but they all support the same cellular network. Taken together or separately, they offer complementary ways to help support the foundation of cellular energy and healthy aging.*
Cellular energy supplements from the same brand or targeted line provide consistency and make it easy to build a strong stack. By combining complementary approaches to NAD+ support, they can help simplify your routine while supporting the cellular processes linked to healthy aging.*
As always, talk with your healthcare provider before starting any new supplement, especially if you're pregnant, nursing, or taking medication.
How to Choose the Best NAD+ Supplement
When searching for high-quality NAD+ supplements, the best NMN supplements, and premium NADH supplements, look for brands that have rigorous testing protocol, GMP-certified facilities, and a legacy of trust, like Solaray’s UNLIMIT line.
Featured Products: Our Recommendations
Solaray Liposomal NAD+
NAD+ is a vital coenzyme that helps mediate multiple major biological processes, including calcium homeostasis, energy metabolism, cell death, mitochondrial function, and aging.* Solaray Liposomal NAD+ uses liposomal technology designed for optimal absorption.
Solaray NMN (Nicotinamide Mononucleotide)
NMN is a precursor to NAD+ that has been clinically studied to increase NAD+ levels. Excellent for those seeking to increase NAD+ levels that support cellular energy.* Solaray NMN contains a dose that has been clinically studied for increased NAD+ levels.
Solaray NADH
NADH is critical for cells to work at an optimal level. NADH supports cellular energy and helps mediate multiple major biological processes including calcium homeostasis, energy metabolism, mitochondrial functions, cell death, and aging.*
Frequently Asked Questions
Q: What is the best NAD+ supplement?
A: The best NAD+ supplement depends on your goals. Liposomal NAD+ is designed for optimal absorption, NMN is a direct precursor to NAD+, and NADH provides excellent support for cellular energy.*
Q: How do NAD+ molecules support mitochondrial function in the body?
A: NAD+ facilitates mitochondrial biogenesis and ATP production through the SIRTs-PPARGC1A axis. NADH feeds electrons into the electron transport chain to generate ATP.9
Q: Do high-protein diets affect NAD+?
A: Yes. High-fat and high-protein diets affect NAD+ synthesis and are associated with reduced levels of this important molecule.4
Ready to Support Your Cellular Health?
Explore Solaray’s UNLIMIT line of longevity supplements, including Liposomal NAD+, NMN, and NADH. All backed by 50 years of quality, testing, and trust.
Resources
1 Covarrubias, A. J., Perrone, R., Grozio, A., & Verdin, E. (2021). NAD+ metabolism and its roles in cellular processes during ageing. Nature Reviews Molecular Cell Biology, 22(2), 119-141.
2 McReynolds, M. R., Chellappa, K., & Baur, J. A. (2020). Age-related NAD+ decline. Experimental Gerontology, 134, 110888.
3 Song, Q., Zhou, X., Xu, K., Liu, S., Zhu, X., & Yang, J. (2023). The safety and antiaging effects of nicotinamide mononucleotide in human clinical trials: An update. Advances in Nutrition, 14(6), 1416-1435.
4 Yang, X., Hua, L., Gao, D., Wu, Y., Yang, Y., Jin, X., Jiang, X., Jin, C., Feng, B., Che, L., Xu, S., Lin, Y., Jin, L., Zhuo, Y., Li, M., & Wu, D. (2026). Long-term high-protein diet intake accelerates adipocyte senescence through macrophage CD38-mediated NAD+ depletion. Molecular Metabolism, 103, 102306.
5 López-Otín, C., Blasco, M. A., Partridge, L., Serrano, M., & Kroemer, G. (2013). The hallmarks of aging. Cell, 153(6), 1194-1217.
6 LibreTexts. (2026). Electron transport and oxidative phosphorylation. Introductory Biochemistry.
7 Ying, W. (2006). NAD+ and NADH in cellular functions and cell death. Frontiers in Bioscience, 11, 3129-3148. PMID: 16720381
8 Srivastava, S. (2016). Emerging therapeutic roles for NAD+ metabolism in mitochondrial and age-related disorders. Clinical and Translational Medicine, 5, 25. PMID: 27465020.
9 Gleichmann, M., & Mattson, M. P. (2011). Neuronal calcium homeostasis and dysregulation. Antioxidants & Redox Signaling, 14(7), 1261-1273.
10 Alegre, G. F. S., & Pastore, G. M. (2023). NAD+ precursors nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR): Potential dietary contribution to health. Current Nutrition Reports.
11 Igarashi, M., Nakagawa-Nagahama, Y., Miura, M., Kashiwabara, K., Yaku, K., Sawada, M., et al. (2022). Chronic nicotinamide mononucleotide supplementation elevates blood nicotinamide adenine dinucleotide levels and alters muscle function in healthy older men. NPJ Aging.
12 Okabe, K., Yaku, K., Tobe, K., et al. (2022). Oral administration of nicotinamide mononucleotide is safe and efficiently increases blood nicotinamide adenine dinucleotide levels in healthy subjects. Frontiers in Nutrition. PMID: 35399848.
13 Hale, M. (2026). Liposomal NAD+: Does oral absorption really work?. The NAD Review