What does NAD+ actually do in the body?
NAD+ has two distinct biochemical roles that are both relevant to why its decline matters and why replenishing it is of interest to researchers and clinicians.
The first is electron transport. NAD+ is the primary electron carrier in cellular energy metabolism — cycling between its oxidized form (NAD+) and its reduced form (NADH) to shuttle electrons through glycolysis, the Krebs cycle, and the mitochondrial electron transport chain. Without adequate NAD+, mitochondrial ATP production loses throughput. The cells with the highest energy demands — neurons, muscle cells, cardiac cells — are most sensitive to declining NAD+ pools.
The second role is substrate for regulatory enzymes. Three major enzyme families consume NAD+ rather than recycle it: sirtuins (which regulate gene expression, metabolism, and stress responses), PARPs (which detect and repair DNA damage), and CD38 (an immune enzyme whose activity rises with age and chronic inflammation). When these enzyme families are active — especially CD38 and PARPs responding to cumulative DNA damage — they can deplete NAD+ faster than the body replenishes it.
Together, these two roles explain why NAD+ decline is not just a laboratory finding but a biologically meaningful process with downstream consequences for energy, repair capacity, and cellular aging.
How is NAD therapy delivered: IV vs. subcutaneous injection?
There are two primary clinician-supervised routes for NAD+ administration in the current landscape: intravenous (IV) infusion and subcutaneous injection.
Intravenous infusion
IV NAD+ delivers the molecule directly into the bloodstream, producing rapid and measurable increases in circulating NAD+ levels. Research has confirmed that IV administration is effective at raising blood NAD+ concentrations. The experience typically involves a slow drip over one to four hours at a clinic.
Common transient effects during IV infusion include flushing, warmth, chest tightness, nausea, or muscle cramping — all rate-dependent and managed by slowing the infusion. These effects generally resolve within minutes of reducing the drip rate and do not represent lasting side effects. The slow titration protocol that experienced clinics use minimizes their frequency.
Subcutaneous injection
Subcutaneous NAD+ is administered via small injections under the skin, similar to other peptide therapy protocols. It is more convenient for at-home use and avoids the time commitment and infusion-related side effects of IV delivery. Absorption is slower than IV, which may moderate peak plasma levels but allows for more frequent dosing.
For most people pursuing NAD therapy for general wellness, energy, or longevity support outside of a clinical facility, subcutaneous injection is the more practical option. PepScribe’s NAD+ protocol uses compounded NAD+ prepared in the USA by licensed 503A pharmacies — no hidden overseas supply chain — administered subcutaneously on a clinician-designed schedule.
Injection and infusion sidestep the biosynthetic bottlenecks that cap how far an oral pill can raise your NAD+ — that is the core argument for direct therapy.
How does NAD therapy compare to oral NAD+ precursors (NMN, NR)?
The supplement market is saturated with NAD+ precursors: nicotinamide riboside (NR), nicotinamide mononucleotide (NMN), and nicotinamide (niacin). These compounds are real precursors to NAD+ biosynthesis, and some research supports that they can raise NAD+ levels — particularly in muscle tissue, where uptake is more efficient.
The distinction from direct NAD+ therapy is meaningful. Oral precursors must clear the gut, survive first-pass liver metabolism, and go through several enzymatic conversion steps before becoming NAD+. Conversion efficiency varies between individuals, declines with age, and is subject to rate-limiting enzymes that can become bottlenecks.
Direct NAD+ administration bypasses these conversion steps entirely. Whether that translates to meaningfully different clinical outcomes for wellness applications is an active area of research — but the pharmacokinetic argument for direct administration is straightforward and has been confirmed in human studies.
What do people seek NAD therapy for?
The most common reasons adults pursue NAD therapy under clinician supervision:
- Energy and mitochondrial support: The most mechanistically supported application. ATP production depends directly on NAD+ availability, and declining NAD+ in mitochondria is a well-documented feature of cellular aging.
- Cognitive clarity and focus: Neurons are among the most metabolically demanding cells in the body and among the most sensitive to NAD+ decline. The connection between NAD+ and brain energy metabolism is a subject of active research.
- Recovery after exercise or illness: Physical stress drives higher NAD+ consumption through muscle repair processes and immune activation. Some athletes use NAD therapy to support recovery between training sessions.
- Healthy aging and longevity support: The sirtuin pathway — directly dependent on NAD+ — is one of the most studied molecular pathways in aging biology. Supporting sirtuin activity by maintaining NAD+ is a scientifically coherent rationale, even if human lifespan data is not yet available.
- Sleep quality: NAD+ supports circadian rhythm regulation through sirtuin-dependent mechanisms. Some patients report improved sleep architecture during NAD therapy protocols.
None of these applications constitute treatment for a diagnosed disease, and no outcome can be guaranteed for any individual. Compounded NAD+ is not an FDA-approved drug. What clinician-supervised NAD therapy offers is a biologically grounded, personalized protocol with ongoing monitoring — not a blanket wellness claim.
What does an NAD therapy protocol involve?
A clinician-designed NAD therapy protocol typically involves an initial loading phase — higher frequency dosing to replenish substantially depleted levels — followed by a lower-frequency maintenance phase. The specific parameters (dose, frequency, duration) are individualized based on health history, goals, activity level, and response.
At PepScribe, NAD+ is compounded in the USA by licensed 503A pharmacies and delivered to you directly. A licensed clinician reviews your intake and determines the appropriate protocol. Check-ins let clinicians adjust based on your actual response rather than a one-size-fits-all schedule.
Early responders often notice changes in energy and mental clarity within one to two weeks. Others take longer. The experience is individual — which is exactly why ongoing clinician oversight matters.
Frequently asked questions
What is NAD therapy?
NAD therapy refers to clinician-administered protocols — typically intravenous infusion or subcutaneous injection — that deliver nicotinamide adenine dinucleotide (NAD+) to replenish declining cellular levels. It differs from oral NAD+ precursor supplements, which rely on the body converting precursors to NAD+ through biosynthesis pathways.
Does NAD therapy actually work?
Human research on NAD+ repletion shows it can meaningfully raise circulating NAD+ levels. Whether rising NAD+ translates to specific outcomes — improved energy, better cognitive function, slower biological aging — is under active investigation. The mechanism is scientifically grounded; the clinical benefit size in healthy adults remains an open research question.
What are the benefits of NAD therapy?
People receiving NAD therapy commonly report improved energy, mental clarity, and sleep quality. The strongest theoretical basis is in energy metabolism and DNA repair support. No specific benefit can be guaranteed for any individual, and NAD therapy is not a treatment or cure for any disease.
How long does NAD therapy take to work?
Many people report noticing changes in energy and mental clarity within the first one to two weeks of an injection protocol. IV infusions often produce faster subjective effects. Individual response varies substantially — some notice changes quickly, others require several weeks.
Who is NAD therapy for?
NAD therapy is most commonly pursued by adults seeking support for energy metabolism, cognitive performance, active recovery, and healthy aging. A clinician review determines whether NAD+ is appropriate for a given patient based on health history and goals.
Is NAD therapy safe?
Compounded NAD+ prepared by licensed 503A pharmacies and administered under clinician supervision has a well-documented safety profile. IV infusion can cause transient side effects including flushing or chest tightness during the infusion — these are rate-dependent and resolve on slowing the drip. Subcutaneous injection is generally well tolerated with fewer infusion-related effects.