07/05/2026
By midlife, your NAD+ levels have fallen to roughly half of what they were in your 20s.
NAD+ is a coenzyme present in every living cell. It powers the mitochondria, drives DNA repair, and activates sirtuins - the proteins most closely associated with cellular longevity and resilience. When researchers study the biological hallmarks of ageing, NAD+ depletion appears consistently across the mechanisms that drive cellular deterioration over time.
It's worth being transparent: the human evidence is still maturing, and decline is most clearly documented in skeletal muscle, skin, and the brain. The trajectory, however, is consistent and clinically meaningful.
What is not in question is the foundation: resistance training, quality sleep, reduced alcohol consumption, and a whole-food diet rich in tryptophan and B vitamins all meaningfully support the body's ability to produce NAD+. These are the interventions worth prioritising before targeted supplementation is layered in.