NAD+ Explained: Why It Depletes With Age and How to Support It

NAD+ has become one of the most talked-about molecules in longevity science. Here's a clear-eyed look at what it is, why it matters, and what the research actually supports.

What is NAD+?

NAD+ (nicotinamide adenine dinucleotide) is a coenzyme found in every living cell. It plays a central role in energy metabolism — specifically in the conversion of nutrients into ATP, the fuel your cells run on. It also acts as a critical signaling molecule, activating proteins like sirtuins and PARP enzymes that regulate DNA repair, inflammation, and cellular stress responses.

Why does NAD+ decline with age?

NAD+ levels drop significantly as we age — by some estimates, levels in middle age are roughly half of what they were in youth. Several factors drive this:

  • Increased consumption — DNA damage, inflammation, and metabolic stress all consume NAD+ at higher rates as we age
  • Reduced synthesis — the body becomes less efficient at producing NAD+ from dietary precursors
  • Sirtuin and PARP competition — these repair enzymes compete for available NAD+, further depleting the pool

What does the research show?

Studies in animal models have shown that restoring NAD+ levels can improve mitochondrial function, metabolic health, and markers of aging. Human research is still emerging, but early trials have demonstrated that NAD+ precursors (like NMN and NR) can effectively raise NAD+ levels in blood and tissues.

Direct NAD+ supplementation — rather than precursors — is an area of active investigation, with researchers exploring bioavailability and tissue-specific effects.

NAD+ vs NMN vs NR — what's the difference?

  • NAD+ — the active coenzyme itself
  • NMN (nicotinamide mononucleotide) — a direct precursor; converts to NAD+ in cells
  • NR (nicotinamide riboside) — a precursor to NMN; one step further back in the pathway

The debate around which form is most effective — and most bioavailable — is ongoing in the research community.

A note on sourcing

As with all peptides and research compounds, purity and sourcing matter enormously. At Avivim Wellness, our NAD+ is sourced with transparency and quality as a priority.

As with any supplement or research compound, consult with a qualified healthcare provider before use.