The decline of NAD+ with age has emerged as one of the most actionable findings in longevity research. This coenzyme — essential for over 500 enzymatic reactions — drops by approximately 50% between ages 40 and 60 in human tissue studies. The functional consequences of this decline, and the effects of restoring NAD+ levels, have become a central focus of aging science.
NAD+ in Cellular Function
NAD+ serves two fundamental roles: as an electron carrier in metabolic reactions (accepting and donating electrons in the citric acid cycle and oxidative phosphorylation) and as a substrate consumed by enzymes including sirtuins (SIRT1-7), PARPs (poly-ADP-ribose polymerases), and CD38. The latter role means NAD+ is continuously consumed and must be regenerated — creating a supply-demand balance that shifts unfavorably with age.
NAD+ and Sirtuins
Sirtuins are a family of NAD+-dependent deacetylases and ADP-ribosyltransferases that regulate genomic stability, mitochondrial function, inflammatory responses, and metabolic flux. SIRT1 (nuclear) deacetylates key transcription factors including PGC-1alpha (mitochondrial biogenesis), FOXO (stress resistance), and NF-kB (inflammation). Without adequate NAD+, sirtuin activity is impaired.
The NAD+ Decline in Aging
Multiple mechanisms drive age-related NAD+ decline: increased activity of the NAD+-consuming enzyme CD38 (which rises with chronic inflammation), reduced expression of NAD+ biosynthetic enzymes (NAMPT), and increased PARP activity due to accumulating DNA damage. The result is a vicious cycle where NAD+ depletion impairs the very repair mechanisms (sirtuins, PARPs) needed to maintain cellular health.
NAD+ Restoration Research
In aged mice, NAD+ supplementation has reversed mitochondrial dysfunction, improved insulin sensitivity, enhanced stem cell function, reduced inflammatory markers, and — in some studies — extended lifespan. These findings have been replicated across multiple laboratories and model organisms, establishing NAD+ restoration as one of the most reproducible interventions in aging research.
Research-Grade NAD+
NAD+ is available in 500mg and 1000mg lyophilized form at systemicpeptides.com for metabolic and longevity research protocols.