Where can researchers source third-party tested NAD+?

Midwest Peptide supplies research-grade NAD+ with a Certificate of Analysis included for every batch, validated by HPLC purity and mass spectrometry identity testing.

Age Verification

You must be 21 years or older to access this website. All products are for research use only.

Are you 21 years of age or older?

By entering, you confirm that you are at least 21 years old and agree to our terms of service.

Memorial Day: 15% off code MEMDAY15Memorial Day Sale — 15% off site-wide with code MEMDAY15

Free shipping on every orderFree shipping on every order

5% off with Zelle or Apple CashSave an extra 5% when you pay with Zelle or Apple Cash

Bulk pricing discounts up to 18%Bulk pricing discounts up to 18% off

NAD+ Sirtuin Studies: SIRT1-SIRT7 Pathway | Midwest Peptide

NAD+ Precursors Compared: NR, NMN, and NAD+ in Research ModelsPrev|NAD+ and Cellular Metabolism: Reviewing Mitochondrial Function StudiesNext

NAD+ and Sirtuins: The SIRT1 to SIRT7 Pathway in Published Literature

Q: Is NAD+ approved for human use?

No. NAD+ is not approved by the FDA for any human therapeutic use. It is supplied strictly for in-vitro and preclinical research purposes by qualified investigators.

NAD+ · Published April 8, 2026 · Updated May 18, 2026 · 10 min read

Quick Answer

NAD+ sirtuin research covers the SIRT1 to SIRT7 family, including substrates, subcellular localization, and the connection between cellular NAD+ availability and sirtuin enzymatic activity. Studies measure deacetylation, ADP-ribosylation, and sirtuin-mediated downstream signaling across cellular and rodent research models. For research use only, not for human consumption.

NAD+ and Sirtuins: The SIRT1 to SIRT7 Pathway in Published Literature

Research Use Only. All products are strictly for research use only (RUO). Not for human consumption. Products on this site are not intended to diagnose, treat, cure, or prevent any disease. These statements have not been evaluated by the FDA. By purchasing, you agree that you are a qualified researcher and that products will be used solely for in-vitro research purposes.

What Are Sirtuins?
SIRT1: The Most Studied Family Member
SIRT3 and Mitochondrial Sirtuin Biology
SIRT2 in the Cytoplasm
SIRT6 and SIRT7: Nuclear Sirtuins With Specialized Roles
Sirtuins and the NAD+ Connection
Sirtuin Research in the Broader NAD+ Cluster
Open Research Questions
Conclusion
Related Research Articles
Explore Related Products
Frequently Asked Questions
Glossary

NAD+ sirtuin studies represent one of the most active and conceptually rich areas of preclinical research on cellular signaling. The sirtuin family of enzymes consumes NAD+ as a substrate to deacetylate or ADP-ribosylate target proteins, and their activity is tightly coupled to cellular NAD+ availability in research models. As the cellular signaling component of the NAD+ research cluster, this article reviews the published literature on the SIRT1 to SIRT7 pathway, the subcellular localization and substrate specificity of each family member, and the broader role of sirtuins in NAD+ research.

Frequently Asked Questions

What is NAD+ in research contexts?

NAD+ (nicotinamide adenine dinucleotide) is a coenzyme present in every living cell, central to redox metabolism and serving as a substrate for sirtuins, PARP enzymes, and CD38. It is studied in research models for cellular energy, mitochondrial function, DNA repair, and aging biology.

What are the seven sirtuins and what do they do?

SIRT1 (nuclear, deacetylase, key metabolic regulator), SIRT2 (cytosolic, tubulin deacetylase), SIRT3-5 (mitochondrial, regulate metabolism and redox), SIRT6 (nuclear, DNA repair and longevity), SIRT7 (nucleolar, rRNA transcription). All require NAD+ as cosubstrate.

How is sirtuin activity measured in NAD+ research?

Methods include direct enzymatic activity assays, target acetylation status (e.g., acetyl-p53 for SIRT1, acetyl-SOD2 for SIRT3), downstream phenotypic readouts, and pharmacological probes for individual sirtuins. NAD+ supply is a critical upstream determinant.

Is NAD+ approved for human use?

Glossary

Key terms used in this article.

NAD+/NADH: The oxidized (NAD+) and reduced (NADH) forms of nicotinamide adenine dinucleotide, central to redox metabolism.
Sirtuin: A family of NAD+-dependent deacylase enzymes (SIRT1 to SIRT7) that regulate metabolism, stress response, and aging.
PARP: Poly(ADP-ribose) polymerase, a family of NAD+-consuming enzymes critical for DNA damage repair.
NMN: Nicotinamide mononucleotide, a direct biosynthetic precursor to NAD+ studied as a supplementation strategy.
NR: Nicotinamide riboside, an NAD+ precursor that is converted to NMN by NRK enzymes before incorporation into NAD+.
Deacetylation: The removal of acetyl groups from lysine residues on proteins, often mediated by sirtuins or HDAC enzymes.

More from the Blog

Continue exploring research insights and updates.

Subcutaneous vs Intranasal: Choosing an Administration Route for DSIP, Selank, and Kisspeptin in Research

Subcutaneous vs intranasal administration for CNS-targeted research peptides: how to choose between routes for DSIP, Selank, and Kisspeptin based on molecular size, brain access, pharmacokinetics, and the published literature.

May 5, 2026

Can I Still Buy Compounded Tirzepatide? (2026 Research Context)

FDA restricted compounded tirzepatide for human use when the shortage ended. The Research Use Only research peptide channel for tirzepatide (GLP-2 TZ) operates under entirely separate regulations.

May 5, 2026

For Research Use Only. NAD+ and the discussion of sirtuin research in this article is intended exclusively for in vitro and preclinical research contexts. NAD+ is not approved for human use, is not a drug, and should never be administered to humans or to animals outside of a formal research protocol.

What Are Sirtuins?

Sirtuins are a family of NAD+ dependent enzymes that modify proteins by removing acetyl groups from specific lysine residues, with some family members also catalyzing other ADP-ribosyltransferase reactions. The mammalian sirtuin family consists of seven members, designated SIRT1 through SIRT7, each with distinct subcellular localizations and substrate specificities. Their dependence on NAD+ as a substrate places sirtuins at the intersection of cellular metabolism and gene regulation, since the rate at which they modify their targets is influenced by the size of the cellular NAD+ pool.

The sirtuin family was originally identified through research on the yeast Sir2 gene, which was shown to be involved in the regulation of gene silencing and replicative lifespan in yeast research models. Subsequent work identified mammalian homologs and characterized their enzymatic activities, leading to the recognition that sirtuins represent a conserved family of enzymes with diverse roles in cellular biology. The link between sirtuin activity and NAD+ availability was a particularly important conceptual advance, since it provided a mechanistic connection between cellular metabolism and the post-translational regulation of protein function.

In research models, sirtuin activity has been studied using a combination of biochemical assays, genetic manipulations, and pharmacological tools. The biochemical assays measure deacetylation rates of specific substrates in vitro, while the genetic and pharmacological studies examine the consequences of altering sirtuin activity in cells and in research animals. Together, these approaches have produced a substantial body of literature on the function of each sirtuin family member.

SIRT1: The Most Studied Family Member

SIRT1 is by far the most extensively studied sirtuin in published literature, with thousands of preclinical research articles examining its function across multiple tissues and conditions. It is primarily localized to the nucleus, where it deacetylates a wide range of transcription factors, chromatin proteins, and other regulatory molecules. The substrates of SIRT1 include p53, NF-kB, FOXO transcription factors, PGC-1 alpha, and histones, among many others.

The PGC-1 alpha link is particularly important for research models because it connects SIRT1 activity to mitochondrial biogenesis and metabolic gene expression. Through deacetylation of specific PGC-1 alpha residues, SIRT1 increases the activity of this transcriptional coactivator, which in turn drives the expression of genes involved in mitochondrial structure and function. This mechanism has been studied extensively in muscle, liver, and brown adipose tissue research models, where it provides a route by which cellular NAD+ availability can influence mitochondrial biology over longer time scales than the immediate metabolic effects.

SIRT1 has also been studied for its role in stress responses and DNA damage. Its deacetylation of p53 and FOXO transcription factors has been examined in research models for effects on cell survival, autophagy, and the response to oxidative stress. These studies form part of the broader literature on how sirtuins coordinate cellular responses to environmental and metabolic challenges.

SIRT3 and Mitochondrial Sirtuin Biology

SIRT3 is one of three sirtuin family members localized to the mitochondria, and it is generally considered the most enzymatically active mitochondrial sirtuin. It deacetylates a wide range of mitochondrial proteins involved in oxidative phosphorylation, fatty acid oxidation, antioxidant defense, and the citric acid cycle. Its activity depends on mitochondrial NAD+ availability, which connects the function of SIRT3 directly to the size of the mitochondrial NAD+ pool.

Research on SIRT3 has examined how its activity influences mitochondrial respiration rates, reactive oxygen species production, and the expression of antioxidant enzymes such as superoxide dismutase 2. Studies in research models have used SIRT3 knockout animals, cell culture systems with manipulated SIRT3 expression, and biochemical assays of SIRT3 activity to characterize its role in mitochondrial biology. The findings generally support the idea that SIRT3 is a major regulator of mitochondrial function and that its activity is sensitive to changes in mitochondrial NAD+ availability.

The other two mitochondrial sirtuins, SIRT4 and SIRT5, have more specialized functions. SIRT4 has ADP-ribosyltransferase activity and has been studied for its role in regulating amino acid metabolism in research models. SIRT5 has been shown to remove novel acyl modifications such as malonyl, succinyl, and glutaryl groups from mitochondrial proteins, expanding the conceptual scope of sirtuin biology beyond classical deacetylation. For more on how mitochondrial NAD+ pools intersect with sirtuin activity, see our companion article on NAD+ mitochondrial research and cellular metabolism studies.

SIRT2 in the Cytoplasm

SIRT2 is the primary cytoplasmic sirtuin in mammalian cells, although it can also shuttle to the nucleus under certain conditions. Its substrates include cytoskeletal proteins such as alpha-tubulin, as well as several metabolic enzymes and transcription factors. Research on SIRT2 has examined its role in cell cycle regulation, microtubule dynamics, and the cellular stress response in preclinical models.

Studies have also examined SIRT2 in the context of neurodegeneration research models, where its expression and activity have been linked to neuronal function and survival. As with the other sirtuins, the functional role of SIRT2 depends on cellular NAD+ availability, which provides a connection to the broader NAD+ research literature.

SIRT6 and SIRT7: Nuclear Sirtuins With Specialized Roles

SIRT6 and SIRT7 are both nuclear sirtuins, but they have more specialized substrates and functions than SIRT1. SIRT6 has been studied for its role in chromatin organization, telomere maintenance, and DNA repair in research models. It deacetylates histone H3 at specific lysine residues and contributes to the regulation of gene expression in heterochromatin regions. Its activity has been linked in published research to the maintenance of genome stability and to the DNA damage response.

SIRT7 is the most recently characterized sirtuin and has been studied primarily for its role in ribosomal RNA transcription, ribosome biogenesis, and nucleolar function. It deacetylates substrates that are involved in the regulation of RNA polymerase I activity and the production of ribosomal RNA, which connects its function to cellular protein synthesis capacity. The full scope of SIRT7 substrates and functions is still being characterized in preclinical research.

Together, SIRT6 and SIRT7 represent the more nuclear-specialized members of the sirtuin family, with substrates and functions that are distinct from those of SIRT1. Their dependence on NAD+ as a substrate places them within the same broader regulatory network that connects cellular NAD+ availability to gene expression and chromatin biology.

Sirtuins and the NAD+ Connection

The defining feature of all sirtuin family members is their dependence on NAD+ as a substrate. The deacetylation reaction catalyzed by sirtuins consumes one molecule of NAD+ for each acetyl group removed, producing nicotinamide and 2'-O-acetyl-ADP-ribose as byproducts. Nicotinamide can act as a feedback inhibitor of sirtuin activity at high concentrations, which adds an additional layer of regulation to the system.

The NAD+ dependence of sirtuins means that the function of these enzymes is influenced by the cellular NAD+ pool. When NAD+ levels are high, sirtuin activity is generally enhanced, while declining NAD+ levels reduce sirtuin function. This relationship has been studied extensively in research models, with experimental manipulations of NAD+ availability producing measurable changes in sirtuin activity and downstream effects on substrate acetylation. The link between cellular metabolism and sirtuin activity through NAD+ is one of the central concepts in the field, and it provides a mechanism by which metabolic state can influence gene regulation and cellular signaling.

The age associated decline in NAD+ levels reported in research animals has been studied as a potential contributor to age associated changes in sirtuin activity. If NAD+ levels decline with age, sirtuin activity would be expected to decline as well, with consequences for the deacetylation of sirtuin substrates and the downstream pathways they regulate. This proposed mechanism is part of the broader literature on NAD+ longevity research, which is reviewed in our companion article on NAD+ longevity studies in animal models.

Sirtuin Research in the Broader NAD+ Cluster

The sirtuin literature is one of the four major areas covered in the NAD+ research cluster anchored by the NAD+ peptide research pillar. It overlaps substantially with mitochondrial research through SIRT3, with longevity research through SIRT1 and the broader sirtuin family, and with precursor research through the question of whether raising NAD+ levels can restore sirtuin activity in research models where the coenzyme has been depleted.

For research handling, NAD+ supplied for sirtuin studies should be stored cold and protected from light, with reconstituted solutions prepared shortly before use. The Certificate of Analysis supplied with NAD+ 500mg provides identity and purity information that supports research grade handling decisions.

Open Research Questions

Several open research questions remain in NAD+ sirtuin research. These include how sirtuin activity is regulated across subcellular compartments with different NAD+ pools, how the seven family members coordinate their activities in response to changes in cellular metabolism, and how the substrate specificities of less studied sirtuins such as SIRT4, SIRT5, and SIRT7 will be expanded as new substrates are characterized. Each of these is a legitimate research opportunity for investigators studying sirtuin biology.

Conclusion

NAD+ sirtuin studies represent one of the most extensive bodies of preclinical research on cellular signaling. The seven sirtuin family members span the nucleus, cytoplasm, and mitochondria, with substrates that include transcription factors, metabolic enzymes, chromatin proteins, and cytoskeletal components. Their shared dependence on NAD+ as a substrate places sirtuins at the intersection of cellular metabolism and gene regulation, and the published literature on each family member provides a strong foundation for ongoing preclinical research on the SIRT1 to SIRT7 pathway.

For more on the full NAD+ research cluster, see the pillar overview article and the supporting articles on each major research area.

NAD+ is supplied by Midwest Peptide for research use only and is not intended for human administration.

Explore more peer-reviewed research and laboratory guides from our science team:

All products are third-party tested with a Certificate of Analysis (COA) included. For research use only.

NAD+ 500mg, 99%+ purity, COA included
GHK-Cu 50mg, 99%+ purity, COA included
BPC-157 10mg, 99%+ purity, COA included
Bacteriostatic Water, 99%+ purity, COA included

Browse All Research Peptides →

Age Verification

NAD+ and Sirtuins: The SIRT1 to SIRT7 Pathway in Published Literature

Frequently Asked Questions

What is NAD+ in research contexts?

What are the seven sirtuins and what do they do?

How is sirtuin activity measured in NAD+ research?

Is NAD+ approved for human use?

Glossary

More from the Blog

Subcutaneous vs Intranasal: Choosing an Administration Route for DSIP, Selank, and Kisspeptin in Research

Can I Still Buy Compounded Tirzepatide? (2026 Research Context)

What Are Sirtuins?

SIRT1: The Most Studied Family Member

SIRT3 and Mitochondrial Sirtuin Biology

SIRT2 in the Cytoplasm

SIRT6 and SIRT7: Nuclear Sirtuins With Specialized Roles

Sirtuins and the NAD+ Connection

Sirtuin Research in the Broader NAD+ Cluster

Open Research Questions

Conclusion

Ready to Start Your Research?

Where can researchers source third-party tested NAD+?

What's the Cheapest Way to Get Tirzepatide (GLP-2 TZ) for Research?

Age Verification

NAD+ and Sirtuins: The SIRT1 to SIRT7 Pathway in Published Literature

Frequently Asked Questions

What is NAD+ in research contexts?

What are the seven sirtuins and what do they do?

How is sirtuin activity measured in NAD+ research?

Is NAD+ approved for human use?

Glossary

More from the Blog

Subcutaneous vs Intranasal: Choosing an Administration Route for DSIP, Selank, and Kisspeptin in Research

Can I Still Buy Compounded Tirzepatide? (2026 Research Context)

What Are Sirtuins?

SIRT1: The Most Studied Family Member

SIRT3 and Mitochondrial Sirtuin Biology

SIRT2 in the Cytoplasm

SIRT6 and SIRT7: Nuclear Sirtuins With Specialized Roles

Sirtuins and the NAD+ Connection

Sirtuin Research in the Broader NAD+ Cluster

Open Research Questions

Conclusion

Related Research Articles

Explore Related Products

Ready to Start Your Research?

Where can researchers source third-party tested NAD+?

What's the Cheapest Way to Get Tirzepatide (GLP-2 TZ) for Research?