Overview
In plain English
NAD+ is not a peptide. It is a dinucleotide every cell uses as the principal hydride carrier of energy metabolism and as the consumed substrate for its DNA-repair and signalling enzymes.
Tissue levels decline with age. It is studied in published research for mitochondrial function, sirtuin-dependent signalling, PARP-mediated DNA repair capacity and age-associated NAD+ decline. Strictly for laboratory research use. Not for human or veterinary consumption.
- What it isA coenzyme central to energy metabolism and DNA repair
- Mainly studied forSirtuin and PARP signalling, mitochondrial function, age-related NAD+ decline
- Supplied asLyophilised powder, 1000mg vial, independently assayed
How it works
What it actually does
NAD+ has two jobs, and mixing them up is the most common mistake made about it.
The first is energy. It shuttles electrons through the reactions that convert substrates into ATP, and is recycled each time rather than used up.
The second is maintenance. A group of repair and signalling enzymes — the sirtuins and the PARPs among them — physically consume NAD+ every time they act. That is where supply becomes the limit, and why the age-related decline is the focus of the research.
The science in detail
NAD+ occupies two distinct roles in cell biology, and conflating them is the commonest error in describing it.
The first is catalytic. As the NAD+/NADH couple it is the principal hydride acceptor of intermediary metabolism, cycling through several hundred dehydrogenase reactions: GAPDH in glycolysis, the isocitrate, α-ketoglutarate and malate dehydrogenases of the TCA cycle, and the dehydrogenase steps of β-oxidation. NADH then delivers electrons to complex I. In this role NAD+ is regenerated, not consumed, and the ratio of oxidised to reduced forms — rather than absolute quantity — sets the direction of flux. Phosphorylation by NAD kinase yields NADP+, whose reduced form NADPH drives reductive biosynthesis and regenerates glutathione and thioredoxin.
The second role is as a consumed substrate. Sirtuins (SIRT1–7) are NAD+-dependent deacylases: each turnover cleaves NAD+, releasing nicotinamide and 2'-O-acyl-ADP-ribose. PARP1 and PARP2 consume it heavily during poly-ADP-ribosylation in the DNA damage response. The ecto-enzymes CD38 and CD157 hydrolyse it to cyclic ADP-ribose, and SARM1 consumes it during axonal degeneration. Because these enzymes destroy the molecule, their activity is constrained by NAD+ availability — the basis for research linking NAD+ concentration to sirtuin signalling.
Supply comes mainly from the salvage pathway, where NAMPT converts nicotinamide to NMN and the compartment-specific NMNAT isoforms adenylylate it to NAD+ in nucleus, cytosol and mitochondria. De novo synthesis from tryptophan via the kynurenine pathway and the Preiss-Handler route from nicotinic acid contribute less. Tissue NAD+ declines with age, with increased CD38 expression among the implicated mechanisms (Camacho-Pereira et al., Cell Metabolism, 2016).
What distinguishes NAD+ from its precursors is transport. It is a large, doubly charged dinucleotide with poor membrane permeability, and extracellular NAD+ is substantially degraded by CD38 and CD73 to NMN and NR before uptake. Whether raising intracellular NAD+ is better served by the dinucleotide itself or by precursors remains an open question in the literature (Rajman, Chwalek and Sinclair, Cell Metabolism, 2018).
Evidence
What the research shows
Two roles: fuel and maintenance
It is recycled endlessly in energy production, but permanently consumed by repair and signalling enzymes.
Repair enzymes consume it
Sirtuins and DNA-repair enzymes destroy NAD+ each time they act, so their activity is limited by availability.
Tissue levels decline with age
Published work links the decline partly to CD38, an enzyme whose expression rises with age.
Poor membrane permeability
NAD+ crosses cell membranes poorly and is degraded extracellularly by CD38 and CD73, which is why route of delivery is an open question in the literature.
Reconstitution & handling
Reconstitution and handling in the laboratory
These are general handling notes for the lyophilised dinucleotide supplied by Purist Peptides. They describe the preparation of a stock solution for laboratory work. They are not a dosing protocol, and they describe no administration to a person or an animal.
A 3ml vial of bacteriostatic water is included free with every peptide vial you order, so the material can be reconstituted on arrival.
NAD+ 1000mg — preparing a stock solution
Choice of diluent
Bacteriostatic water (water for injection with 0.9% benzyl alcohol) is the usual diluent where a stock will be drawn from repeatedly, because the preservative permits several septum entries across a working period. Sterile water for injection and sterile 0.9% sodium chloride are both used where a single-use preparation is wanted instead. The diluent volume sets the concentration of the stock, so record it.
Sterile technique
- Allow the sealed vial to reach room temperature before opening the carton — reconstituting a cold lyophilised cake slows dissolution
- Work in a clean area or a laminar flow cabinet, and wipe the rubber septum with 70% isopropyl alcohol, letting it dry fully
- Draw the chosen volume of diluent using a sterile single-use syringe and needle
- Angle the needle so the diluent runs down the inside wall of the vial — do not direct the stream onto the lyophilised cake
- Roll the vial gently between the palms until the cake has dissolved completely. Do not shake and do not vortex: peptides are surface-active, and agitation drives foaming and aggregation
- Let the vial stand for 5 to 10 minutes. A correctly reconstituted solution is clear and free of visible particles
Working out the concentration
Concentration follows from the mass in the vial and the volume of diluent added, nothing else. Adding 2ml of diluent to the 1000mg vial gives a 500mg/ml stock; adding 4ml gives 250mg/ml. Label every reconstituted vial with its concentration and the date it was prepared.
Storage and stability
Before reconstitution
The lyophilised powder is the stable form. Sealed vials are best held at −20°C, protected from light and from moisture; the short periods at 2 to 6°C that occur in transit and on arrival are expected and are accounted for in the supply chain. Keep the vial in its carton — light and humid air are the two ordinary causes of loss on storage.
After reconstitution
Hold reconstituted solution at 2 to 6°C and protect it from light. Do not freeze a working stock: freeze-thaw cycling is the main avoidable cause of degradation and of visible precipitate. Where material must be held beyond a short working period, aliquot the stock into sterile low-binding tubes and freeze the aliquots once at −20°C or below, thawing each aliquot only once.
NAD+ is less stable in solution than the peptides in this range: the nicotinamide-ribose glycosidic bond hydrolyses under alkaline conditions and the molecule degrades with heat and light. Prepare the stock close to the point of use. The lyophilised powder is strongly hygroscopic, so keep sealed vials desiccated and open them only at room temperature.
Checks before use
Inspect every vial against a light source. Discard any solution that is hazy, discoloured or contains particles, and any vial whose septum integrity is in doubt. The independent HPLC assay report for the batch supplied is available on request.
Strictly for laboratory research use. Not for human or veterinary consumption.
Questions
Frequently asked questions
Is NAD+ a peptide?
No. It is a dinucleotide — nicotinamide mononucleotide joined to adenosine monophosphate through a pyrophosphate bridge. It is stocked alongside research peptides because it is handled and reconstituted in the same way, not because it belongs to the same chemical class.
How does NAD+ differ from NMN and NR?
NMN and NR are biosynthetic precursors that enter the salvage pathway upstream of NAD+. Both are smaller and more readily transported. NAD+ itself is doubly charged and poorly membrane-permeant, and extracellular NAD+ is largely degraded to NMN and NR by CD38 and CD73 before it reaches the cell interior.
What is it studied for?
Research contexts include mitochondrial function, sirtuin-dependent signalling, DNA repair capacity via PARP activity, and age-associated decline in tissue NAD+ concentration. Rajman, Chwalek and Sinclair (Cell Metabolism, 2018) review the in vivo evidence for NAD-boosting strategies.
Why is it less stable than the peptides you supply?
The nicotinamide-ribose glycosidic bond hydrolyses under alkaline conditions and degrades with heat and light. Lyophilised NAD+ is also strongly hygroscopic. Both properties argue for preparing solutions close to the point of use and keeping the dry powder sealed and desiccated.
How is purity verified?
Every batch is assayed by Bioindustrial Services in Boksburg, an independent biotechnology laboratory, using HPLC. We do not self-certify. The signed certificate of analysis for each batch — lab number, method and assayed result — is published on our quality standards page.
How long does delivery take?
Orders are dispatched from within South Africa with tracking. Timelines by region and courier are set out on our delivery process page.
Can I return an order?
Because these are laboratory compounds, returns are not accepted once an order has shipped. If your parcel arrives damaged, contact us within 48 hours with photographs of the packaging and product and we will arrange a replacement. The full terms are set out in our refund policy.
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