NAD+

NAD+ Peptide

NAD⁺, or nicotinamide adenine dinucleotide, represents the oxidized form of NADH. Its primary biological role is to facilitate the transfer of electrons between biochemical reactions, thereby aiding in the movement of energy within cells and, under certain conditions, to extracellular environments. Beyond its role in energy metabolism, NAD⁺ is also involved in regulating enzyme activity, posttranslational protein modifications, and intercellular communication. As an extracellular signaling molecule, NAD⁺ has been observed to be released by neurons in various tissues, including blood vessels, the bladder, the large intestine, and specific regions of the brain.

NAD+ Peptide Overview

Scientific studies indicate that Nicotinamide Adenine Dinucleotide (NAD⁺) functions as a critical coenzyme for several enzyme families that regulate essential cellular processes related to metabolism, DNA repair, and cell signaling. The three primary enzyme classes that depend on NAD⁺ include:

• Deacetylase enzymes in the sirtuin class (SIRTs):
  These enzymes play a central role in regulating gene expression, energy metabolism, and cellular stress responses. Sirtuins influence aging, inflammation, and mitochondrial function by removing acetyl groups from target proteins in an NAD⁺-dependent manner. Elevated sirtuin activity has been linked to improved metabolic efficiency, enhanced longevity, and protection against oxidative damage.
  
  
• Poly(ADP-ribose) polymerase (PARP) enzymes:
  PARP enzymes are key to maintaining genomic stability through their role in DNA damage detection and repair. When DNA strands break, PARPs use NAD⁺ to form poly(ADP-ribose) chains that recruit repair proteins to the damaged sites. Excessive PARP activation, however, can deplete NAD⁺ reserves and impair cellular energy balance, a process associated with neurodegenerative and metabolic diseases.
  
  
• Cyclic ADP ribose synthetase (cADPRS):
  These enzymes are responsible for generating cyclic ADP-ribose, a potent secondary messenger that regulates calcium signaling within cells. Calcium release mediated by cADPRS influences processes such as muscle contraction, neurotransmission, and hormone secretion, highlighting NAD⁺’s indirect but critical role in intracellular communication and physiological regulation.

NAD+ Peptide Research

Scientific Evidence on NAD⁺-Dependent Interactions

Current research highlights several key biological interactions involving Nicotinamide Adenine Dinucleotide (NAD⁺) that play crucial roles in maintaining cellular health, regulating metabolism, and supporting repair mechanisms:

• Sirtuins (SIRTs):
  These NAD⁺-dependent enzymes are vital for maintaining mitochondrial function, regulating energy balance, and promoting stem cell longevity and regeneration. Sirtuins have also been shown to protect against oxidative stress and neural degeneration, suggesting their potential involvement in neuroprotection and age-related disease prevention.
  
  
• Poly(ADP-ribose) Polymerases (PARPs):
  The PARP enzyme family, consisting of 17 known members, utilizes NAD⁺ to generate poly(ADP-ribose) chains that are essential for DNA damage detection and genomic stability. By activating DNA repair pathways, PARPs safeguard cells from genotoxic stress, although excessive activation may deplete NAD⁺ levels and impair cellular metabolism.
  
  
• Cyclic ADP Ribose Synthetases (cADPRS):
  This enzyme group includes CD38 and CD157, both of which are key immunoregulatory enzymes that catalyze NAD⁺ hydrolysis. These reactions influence calcium signaling and may promote DNA repair, stem cell renewal, and proper cell cycle progression, linking NAD⁺ metabolism to immune and regenerative processes.
  
  

Because these enzymatic systems rely heavily on NAD⁺, researchers emphasize that excessive metabolic demand or overactivation of these pathways can reduce NAD⁺ availability, potentially limiting cellular energy balance and repair capacity. Maintaining an optimal equilibrium between NAD⁺ synthesis and utilization may therefore be essential for sustaining the beneficial effects of these biochemical networks.

NAD⁺ Peptide and DNA Repair Following Ischemic Stress

In neuronal culture models exposed to ischemic stress, restoration of NAD⁺ levels has been shown to enhance DNA base-excision repair mechanisms, promote cell survival, and improve the repair of oxidative DNA damage. These effects occur whether NAD⁺ is administered before or after the stress event. Mechanistically, PARP enzymes utilize NAD⁺ to catalyze ADP-ribosylation (PARylation), a process that recruits and activates DNA repair proteins essential for genomic stability. However, excessive DNA damage can lead to PARP overactivation, which rapidly consumes NAD⁺ stores and disrupts other metabolic processes dependent on this molecule. Supplementation of NAD⁺ under such conditions may help counteract depletion, restore cellular energy balance, and support effective DNA repair and neuronal survival.

NAD⁺ Peptide in Liver and Kidney Protection

Experimental studies in animal models demonstrate that increasing circulating NAD⁺ concentrations provides protective metabolic and organ-specific benefits. In models of obesity and alcoholic liver disease, NAD⁺ elevation was linked to improved glucose regulation, enhanced mitochondrial efficiency, and overall better liver function. In aged kidney cells, NAD⁺ supplementation was shown to boost sirtuin (SIRT) enzyme activity and mitigate glucocorticoid-induced hypertrophy, supporting renal cellular resilience. Furthermore, administration of NAD⁺ precursors such as nicotinamide mononucleotide (NMN) has yielded similar results, reducing oxidative stress and protecting against cisplatin-induced nephrotoxicity. These findings highlight NAD⁺’s broad potential in promoting organ repair and metabolic homeostasis.

NAD⁺ Peptide and Skeletal Function

In studies involving aged mice, seven days of nicotinamide mononucleotide (NMN) administration led to higher ATP production, decreased inflammation, and improved mitochondrial efficiency within skeletal tissue. These results align with NAD⁺’s established role as a redox cofactor in cellular energy metabolism. During glycolysis and the citric acid cycle, NAD⁺ accepts electrons to form NADH, which subsequently donates these electrons through the mitochondrial respiratory chain. This electron transfer drives oxidative phosphorylation, facilitating the continuous production of ATP required for muscular energy and endurance.

NAD⁺ Peptide and Cardiac Function

Deficiency of NAD⁺ has been correlated with diminished sirtuin (SIRT) activity, contributing to impaired mitochondrial energy generation and vascular dysfunction, including aortic constriction. In preclinical mouse studies, administration of NMN approximately 30 minutes before induced ischemic injury provided measurable cardioprotective effects, reducing tissue damage and supporting cardiac recovery. These findings suggest that maintaining adequate NAD⁺ availability is vital for optimal heart energy metabolism and resilience to ischemic stress.

Article Author

This literature review was compiled, edited, and organized by Dr. Shin-Ichiro Imai, M.D., Ph.D.

Dr. Imai is a distinguished molecular biologist and longevity researcher best known for his groundbreaking work on NAD⁺ metabolism and sirtuin biology. As a Professor at Washington University School of Medicine in St. Louis, he has made pioneering contributions to understanding how NAD⁺ biosynthesis and signaling pathways influence aging, metabolic balance, and mitochondrial health. His research has provided a critical framework for the development of NAD⁺-enhancing compounds aimed at promoting cellular resilience and healthy aging.

Scientific Journal Author

Dr. Shin-Ichiro Imai has led extensive investigations into the molecular regulation of NAD⁺ synthesis and sirtuin activity, shedding light on their vital roles in energy metabolism, DNA repair, and mitochondrial function. His findings—together with those of noted collaborators such as Dr. David A. Sinclair, Dr. Nady Braidy, Dr. Charles Brenner, Dr. Eric F. Fang, and Dr. Vilhelm A. Bohr—have substantially advanced current knowledge of NAD⁺’s function in neuroprotection, metabolic regulation, and age-related disease prevention.

Dr. Imai and his collaborators are recognized as leading contributors to the scientific foundation of modern NAD⁺ research. This citation is intended solely to acknowledge their academic contributions and is not an endorsement or promotion of this product. Montreal Peptides Canada maintains no professional affiliation, sponsorship, or collaboration with Dr. Imai or any of the researchers referenced herein.

Reference Citations

1.  Schultz, Michael B, and David A Sinclair. "Why NAD(+) Declines during Aging: It's Destroyed." Cell metabolism vol. 23,6 (2016): 965- 966. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5088772/
2. Braidy N, Liu Y. NAD+ therapy in age-related degenerative disorders: A benefit/risk analysis. Exp Gerontol. 2020 Apr;132:110831. doi: 10.1016/j.exger.2020.110831. https://pubmed.ncbi.nlm.nih.gov/31917996/
3. Johnson, Sean, and Shin-Ichiro Imai. "NAD+ biosynthesis, aging, and disease." F1000Research vol. 7 132. 1 Feb 2018. https://www.ncbi. nlm.nih.gov/pmc/articles/PMC5795269/
4. Bieganowski P, Brenner C. Discoveries of nicotinamide riboside as a nutrient and conserved NRK genes establish a Preiss-Handler in- dependent route to NAD+ in fungi and humans. Cell. 2004 May 14;117(4):495-502. https://pubmed.ncbi.nlm.nih.gov/15137942/
5. Fang, E. F., Lautrup, S., Hou, Y., Demarest, T. G., Croteau, D. L., Mattson, M. P., & Bohr, V. A. (2017). NAD+ in Aging: Molecular Mechanisms and Translational Implications. Trends in molecular medicine, 23(10), 899-916. https://www.ncbi.nlm.nih.gov/pmc/articles/P MC7494058/
6. 6 Harden, A; Young, WJ (24 October 1906). "The alcoholic ferment of yeast-juice Part II.--The coferment of yeast-juice". Proceedings of the Royal Society of London. Series B, Containing Papers of a Biological Character. 78 (526): 369-375. https://royalsocietypublishing.or g/doi/10.1098/rspb.1906.0070
7. 7 Mills KF, Yoshida S, Stein LR, Grozio A, Kubota S, Sasaki Y, Redpath P, Migaud ME, Apte RS, Uchida K, Yoshino J, Imai SI. Long-Term Administration of Nicotinamide Mononucleotide Mitigates Age-Associated Physiological Decline in Mice. Cell Metab. 2016 Dec 13;24(6):795-806. https://pubmed.ncbi.nlm.nih.gov/28068222/
8. 8 Long AN, Owens K, Schlappal AE, Kristian T, Fishman PS, Schuh RA. Effect of nicotinamide mononucleotide on brain mitochondrial respiratory deficits in an Alzheimer's disease-relevant murine model. BMC Neurol. 2015 Mar 1;15:19. https://pubmed.ncbi.nlm.nih.gov/25 884176/
9. 9 Safety & Efficacy of Nicotinamide Riboside Supplementation for Improving Physiological Function in Middle-Aged and Older Adults. h ttps://clinicaltrials.gov/ct2/show/NCT02921659
10. 10 Braidy N, Liu Y. NAD+ therapy in age-related degenerative disorders: A benefit/risk analysis. Exp Gerontol. 2020 Apr;132:110831. https:// pubmed.ncbi.nlm.nih.gov/31917996/
11. Wang S, Xing Z, Vosler PS, Yin H, Li W, Zhang F, Signore AP, Stetler RA, Gao Y, Chen J. Cellular NAD replenishment confers marked neuroprotection against ischemic cell death: role of enhanced DNA repair. Stroke. 2008 Sep;39(9):2587-95. https://pubmed.ncbi.nlm.ni h.gov/18617666/
12. Rajman, Luis et al. "Therapeutic Potential of NAD-Boosting Molecules: The In Vivo Evidence." Cell metabolism vol. 27,3 (2018): 529- 547. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6342515/
13. Heer C, et al, Coronavirus infection and PARP expression dysregulate the NAD metabolome: An actionable component of innate im- munity. Journal of Biological Chemistry. Volume 295, Issue 52, Dec 2020. https://www.jbc.org/article/S0021-9258(17)50676-6/fulltext
14. Mehmel, Mario et al. "Nicotinamide Riboside-The Current State of Research and Therapeutic Uses." Nutrients vol. 12,6 1616. 31 May. 2020, doi:10.3390/nu12061616 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7352172/
15. Leung A, Todorova T, Ando Y, Chang P. Poly(ADP-ribose) regulates post-transcriptional gene regulation in the cytoplasm. RNA Biol. 2012 May;9(5):542-8. doi: 10.4161/rna.19899. Epub 2012 May 1. PMID: 22531498; PMCID: PMC3495734.

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STORAGE 

Storage Instructions 

 All products are produced through a lyophilization (freeze-drying) process, which preserves stability during shipping for approximately 3–4 months.

After reconstitution with bacteriostatic water, peptides must be stored in a refrigerator to maintain their effectiveness. Once mixed, they remain stable for up to 30 days.

Lyophilization, also known as cryodesiccation, is a specialized dehydration method in which peptides are frozen and exposed to low pressure. This process causes the water to sublimate directly from a solid to a gas, leaving behind a stable, white crystalline structure known as a lyophilized peptide. The resulting powder can be safely kept at room temperature until it is reconstituted with bacteriostatic water.

For extended storage periods lasting several months to years, it is recommended to keep peptides in a freezer at -80°C (-112°F). Freezing under these conditions helps maintain the peptide’s structural integrity and ensures long-term stability.

Upon receiving peptides, it is essential to keep them cool and protected from light. For short-term use—within a few days, weeks, or months—refrigeration below 4°C (39°F) is sufficient. Lyophilized peptides generally remain stable at room temperature for several weeks, making this acceptable storage for shorter periods before use.

Best Practices For Storing Peptides

Proper storage of peptides is critical to maintaining the accuracy and reliability of laboratory results. Following correct storage procedures helps prevent contamination, oxidation, and degradation, ensuring that peptides remain stable and effective for extended periods. Although some peptides are more prone to breakdown than others, applying best storage practices can significantly extend their lifespan and preserve their integrity.

Upon receipt, peptides should be kept cool and shielded from light. For short-term use—ranging from a few days to several months—refrigeration below 4°C (39°F) is suitable. Lyophilized peptides generally remain stable at room temperature for several weeks, making this acceptable for shorter storage durations.

For long-term preservation over several months or years, peptides should be stored in a freezer at -80°C (-112°F). Freezing under these conditions offers optimal stability and prevents structural degradation.

It is also essential to minimize freeze-thaw cycles, as repeated temperature fluctuations can accelerate degradation. Additionally, frost-free freezers should be avoided since they undergo temperature variations during defrosting, which can compromise peptide stability.

Preventing Oxidation and Moisture Contamination

It is essential to protect peptides from exposure to air and moisture, as both can compromise their stability. Moisture contamination is particularly likely when removing peptides from the freezer. To avoid condensation forming on the cold peptide or inside its container, always allow the vial to reach room temperature before opening.

Minimizing air exposure is equally important. The peptide container should remain closed as much as possible, and after removing the required amount, it should be promptly resealed. Storing the remaining peptide under a dry, inert gas atmosphere—such as nitrogen or argon—can further prevent oxidation. Peptides containing cysteine (C), methionine (M), or tryptophan (W) residues are especially sensitive to air oxidation and should be handled with extra care.

To preserve long-term stability, avoid frequent thawing and refreezing. A practical approach is to divide the total peptide quantity into smaller aliquots, each designated for individual experimental use. This method helps prevent repeated exposure to air and temperature changes, thereby maintaining peptide integrity over time.

Storing Peptides In Solution

Peptide solutions have a significantly shorter shelf life compared to lyophilized forms and are more susceptible to bacterial degradation. Peptides containing cysteine (Cys), methionine (Met), tryptophan (Trp), aspartic acid (Asp), glutamine (Gln), or N-terminal glutamic acid (Glu) residues tend to degrade more rapidly when stored in solution.

If storage in solution is unavoidable, it is recommended to use sterile buffers with a pH between 5 and 6. The solution should be divided into aliquots to minimize freeze-thaw cycles, which can accelerate degradation. Under refrigerated conditions at 4°C (39°F), most peptide solutions remain stable for up to 30 days. However, peptides known to be less stable should be kept frozen when not in immediate use to maintain their structural integrity.

Peptide Storage Containers

Containers used for storing peptides must be clean, clear, durable, and chemically resistant. They should also be appropriately sized to match the quantity of peptide being stored, minimizing excess air space. Both glass and plastic vials are suitable options, with plastic varieties typically made from either polystyrene or polypropylene. Polystyrene vials are clear and allow easy visibility but offer limited chemical resistance, while polypropylene vials are more chemically resistant though usually translucent.

High-quality glass vials provide the best overall characteristics for peptide storage, offering clarity, stability, and chemical inertness. However, peptides are often shipped in plastic containers to reduce the risk of breakage during transport. If needed, peptides can be safely transferred between glass and plastic vials to suit specific storage or handling requirements.

Peptide Storage Guidelines: General Tips

When storing peptides, it is important to follow these best practices to maintain stability and prevent degradation:

• Store peptides in a cold, dry, and dark environment.
• Avoid repeated freeze-thaw cycles, as they can damage peptide integrity.
• Minimize exposure to air to reduce the risk of oxidation.
• Protect peptides from light, which can cause structural changes.
• Do not store peptides in solution long term; keep them lyophilized whenever possible.
• Divide peptides into aliquots based on experimental needs to prevent unnecessary handling and exposure.