There is a molecule inside every cell in your body that is responsible for producing energy, repairing your DNA, regulating inflammation, and communicating with the proteins most closely associated with biological longevity. Most people have never heard of it. Most of the tiredness, mental fog, slow recovery and physical decline that gets attributed to 'getting older' is, at least in part, a consequence of having less of it.
It is called NAD+. Nicotinamide adenine dinucleotide. And understanding what it does — and why you have significantly less of it than you did ten years ago — is arguably the most important thing you can learn about your own biology.
What NAD+ Actually Does
NAD+ is a coenzyme — a molecule that enables other molecules to do their jobs. It functions as an electron carrier in the mitochondria, shuttling electrons through the energy production process that powers every cell in your body. Without sufficient NAD+, your mitochondria cannot produce ATP efficiently. Less NAD+ means less energy at the cellular level, which eventually manifests as the physical and cognitive fatigue most people accept as a normal part of adult life.
Beyond energy production, NAD+ is the essential fuel for a class of proteins called sirtuins — sometimes called longevity proteins. They regulate DNA repair, gene expression, inflammation control, and cellular stress response. They cannot function without NAD+. When NAD+ levels drop, sirtuin activity drops with it.
NAD+ is also required for PARP enzymes — the proteins responsible for detecting and repairing DNA damage. Every cell in your body sustains DNA damage continuously, from metabolic processes, UV exposure, oxidative stress. PARP enzymes fix it. They require NAD+ to do so.
Why It Declines — and When
NAD+ levels begin declining in your late twenties. By fifty, most people have approximately half the NAD+ they had at twenty. The decline happens for several reasons: the body's own production of NAD+ precursors slows with age; the enzymes that consume NAD+ — particularly CD38, which increases with age and inflammation — become more active; and dietary precursors are typically insufficient in modern diets to compensate.
What You Can Do About It
The most direct and well-researched approach to raising NAD+ levels is NMN — Nicotinamide Mononucleotide. NMN is an immediate precursor to NAD+: the body converts it into NAD+ efficiently, and clinical research has consistently demonstrated that NMN supplementation raises NAD+ levels in human subjects.
Lifestyle interventions also support NAD+ levels — caloric restriction, intermittent fasting, and exercise have all demonstrated NAD+-raising effects. But the effect size of supplementation is more consistent and more significant, particularly for adults over thirty-five.
"If you have been taking NMN and felt nothing, the dose or the formulation is almost certainly the explanation. Purity, capsule shell, and extraction quality are not details — they are the product."
Alchemy Fit — The Science Series
Editorial note: This article is for informational and educational purposes only and does not constitute medical advice. These statements have not been evaluated by the MHRA or FSA. Consult a qualified healthcare professional before beginning any supplementation.