How it works
NAD+ is required for redox reactions in mitochondrial energy production and for activating sirtuins and PARP enzymes involved in DNA repair and longevity signaling. Tissue NAD+ levels decline with age.
The evidence
Direct NAD+ supplementation is an active research area. Most strong human evidence is on oral precursors (nicotinamide riboside, nicotinamide mononucleotide) showing measurable increases in tissue NAD+ levels. Direct injection bypasses oral absorption variability.
Typical dosing
Injection: 100–500 mg subcutaneous, 1–3× weekly under clinician supervision. Nasal spray: 50–100 mg daily, intermittently.
Side effects
Common
- Flushing
- Headache
- Nausea (dose-dependent)
Less common
- Injection-site reactions
Drug interactions
- Generally minimal; coordinate with clinician if taking metformin