In 2013, a landmark Harvard study showed that when old mice were given NAD+ precursors, their muscle tissue looked 60% younger within a week. Since then, NAD+ research has exploded — and so has clinical interest from anti-aging physicians, biohackers, and longevity clinics worldwide.
What Is NAD+?
NAD+ stands for nicotinamide adenine dinucleotide. It's a coenzyme found in every living cell — essential for energy production, DNA repair, and the regulation of hundreds of metabolic processes. Without NAD+, your cells cannot generate ATP (the currency of cellular energy), and your DNA repair mechanisms cannot function.
Why NAD+ Declines With Age
NAD+ levels decline significantly with age — dropping roughly 50% between ages 40 and 60 in most tissues. Multiple factors drive this decline:
- Increased activity of CD38, an enzyme that consumes NAD+
- Reduced synthesis from dietary precursors
- Accumulated DNA damage that activates PARP enzymes, which consume NAD+ for repair
- Chronic inflammation, which depletes NAD+ through additional enzymatic pathways
This decline correlates with many hallmarks of aging: reduced energy, slower metabolism, cognitive fog, reduced muscle mass, and impaired cellular repair. Restoring NAD+ levels is therefore a mechanistically compelling anti-aging intervention.
The Benefits: What NAD+ Therapy May Do
Energy and mitochondrial function: NAD+ is the primary fuel for the mitochondrial electron transport chain. Restoring NAD+ levels tends to improve mitochondrial efficiency — which many patients experience as increased energy and reduced fatigue within days of beginning therapy.
Cognitive function: The brain is particularly energy-hungry. NAD+ supports neuronal energy metabolism and has shown neuroprotective effects in research models. Many patients report improved focus, mental clarity, and reduced brain fog — sometimes dramatically.
DNA repair and longevity: NAD+ is required by sirtuins — a family of proteins (SIRT1–SIRT7) often called "longevity genes." Sirtuins regulate gene expression, suppress inflammation, and coordinate cellular stress responses. They also directly repair DNA damage. Higher NAD+ levels mean more sirtuin activity.
Metabolic health: Research links NAD+ restoration to improved insulin sensitivity, reduced inflammation, and better lipid metabolism — all key drivers of metabolic aging.
Delivery Methods: IV vs. Subcutaneous vs. Oral
IV (intravenous): The gold standard for rapid repletion. IV NAD+ bypasses the gut entirely, achieving near-complete bioavailability. Treatments typically run 4–6 hours at a clinic. Many patients experience immediate energy and clarity effects. IV is best for acute repletion or intensive therapeutic use.
Subcutaneous injection: A far more convenient option for ongoing maintenance. Subcutaneous NAD+ delivers the molecule systemically without the time and cost burden of IV infusions. This is the modality PepGenex typically prescribes for at-home maintenance protocols.
Oral (NMN, NR): NMN (nicotinamide mononucleotide) and NR (nicotinamide riboside) are NAD+ precursors available as supplements. They're convenient and have good research backing, but bioavailability varies and peak plasma levels are lower than injectable forms. Oral precursors are a reasonable adjunct or entry-level strategy.
What to Expect
Most patients beginning NAD+ therapy report noticeable changes within 1–2 weeks: improved energy and sleep quality are most commonly cited first. Cognitive effects typically develop over 2–4 weeks. Body composition and metabolic changes emerge over months of consistent use.
IV NAD+ can cause temporary side effects during infusion — flushing, chest tightness, nausea — which typically resolve when the infusion rate is slowed. Subcutaneous NAD+ is generally well-tolerated with minimal side effects.
Who Is NAD+ Therapy For?
NAD+ therapy is most popular with adults 35 and older who are noticing the early signs of biological aging — declining energy, slower recovery, cognitive changes — and want to address them proactively. It's also used therapeutically in addiction recovery programs and for patients with specific neurodegenerative conditions.
At PepGenex, our longevity physicians will assess your baseline health and help design the right NAD+ protocol for your goals — whether that's subcutaneous maintenance dosing, IV repletion, or a combination approach.
This content is for informational purposes only and does not constitute medical advice. Consult a licensed physician before starting any peptide therapy.