There is a quiet process happening inside your body right now — one that affects your energy, your brain, your skin, and your ability to recover. You cannot feel it happening, but its effects build up slowly over the years.

It is the decline of NAD+.

By the time most people reach 50, their NAD+ levels have dropped by roughly half compared to their younger years. By 60, the decline is even steeper. The consequences are felt in every cell, every tissue, every system in the body — yet most people have never even heard of it.

Here is what is really happening, and why it matters more than almost any other health marker you are tracking.

The Numbers Behind the Decline

The research is consistent and striking. Studies measuring NAD+ levels across different age groups show a clear and progressive decline that begins in your 30s and accelerates with each passing decade.

• In your 20s: NAD+ levels are near their peak
• By 40: Levels have dropped by approximately 30–40%
• By 50: You have around half the NAD+ you had in your youth
• By 60+: Levels may fall to as low as 20–30% of youthful concentrations

This is not a minor fluctuation. This is a fundamental shift in your cells' ability to generate energy, repair themselves, and regulate the processes that keep you feeling and functioning well.

Why Does NAD+ Decline?

Several interconnected factors drive the age-related drop in NAD+:

Increased Consumption by CD38

As you age, an enzyme called CD38 becomes increasingly active. CD38 is an NAD+-consuming enzyme — it breaks down NAD+ as part of the immune response. In ageing tissues, CD38 activity increases dramatically, rapidly depleting your NAD+ reserves.

DNA Damage Accumulates

The older you get, the more DNA damage your body has accumulated. Your repair enzymes — PARPs — need NAD+ to work. As they work harder on more damage, they consume NAD+ faster than your body can produce it, creating a deficit.

Declining Production

Your body produces NAD+ through several pathways, most of which become less efficient with age. The enzymes involved in NAD+ biosynthesis slow down, the raw materials needed become less available, and the overall production rate simply cannot keep pace with the demand.

Lifestyle Factors Speed It Up

Poor sleep, chronic stress, alcohol consumption, a sedentary lifestyle, and poor nutrition all accelerate NAD+ depletion beyond what normal ageing alone would cause. Modern life, for most people, puts enormous strain on NAD+ reserves.

What Happens When NAD+ Drops Too Low?

The downstream effects of NAD+ decline touch virtually every aspect of your health:

Energy and Vitality Mitochondria require NAD+ to produce ATP. When NAD+ falls, so does mitochondrial efficiency. The result: chronic fatigue, afternoon energy crashes, and the sense that your body simply cannot generate the power it once could.

Cognitive Performance Your brain is one of the most energy-hungry organs in your body. It is also highly sensitive to NAD+ levels. As NAD+ declines, neurons become less efficient, synaptic signalling slows, and many people begin to experience brain fog, difficulty concentrating, and slower memory recall.

Physical Recovery Athletes and active individuals notice this first. Muscle repair after exercise depends on cellular energy production and DNA repair processes — both of which require adequate NAD+. Lower NAD+ means slower recovery, more soreness, and reduced physical resilience.

Accelerated Ageing Sirtuins — the proteins that regulate inflammation, protect DNA, and support metabolic health — are NAD+-dependent. When NAD+ falls, sirtuin activity drops, and the cellular processes that protect against ageing begin to slow down. This is believed to be one of the central mechanisms driving age-related physical decline.

Curious about whether NAD+ therapy is right for you? Our FAQ page answers the most common questions about who benefits and what to expect.

Can You Stop — or Reverse — the Decline?

The scientific evidence says: yes, you can meaningfully restore NAD+ levels.

The key is choosing a delivery method that actually works. Clinical research consistently shows that oral NAD+ precursors produce limited and inconsistent results in humans. The conversion pathway is inefficient, and much of the supplement is degraded before it reaches circulation.

The approaches that consistently produce measurable increases in plasma NAD+ levels are:

• Intravenous infusions — effective but impractical for regular use
• Subcutaneous injection — the optimal balance of bioavailability, convenience, and consistency

Subcutaneous delivery bypasses the digestive system entirely, delivering NAD+ directly into the tissue where it can be absorbed into the bloodstream at predictable, consistent levels. Research consistently shows this results in significantly higher and more reliable plasma NAD+ concentrations compared to oral supplementation.

The NADvance pen uses a proprietary subcutaneous protocol manufactured to pharmaceutical-grade standards — designed to restore your NAD+ levels reliably, from home.

How Long Before You Notice a Difference?

Individual timelines vary, but most NADvance users report noticing early changes within the first week or two. Improved energy and mental clarity typically come first. Physical recovery improvements and deeper changes in sleep quality often follow over the first month.

By the 30-day mark, many users describe a noticeable and sustained improvement in how they feel overall — not a dramatic, sudden shift, but a gradual return to a more energised, clear-headed baseline.

Want to understand what your first month looks like? Read our detailed guide on how to use the NADvance pen and what to expect as you begin.

The Takeaway

NAD+ decline is one of the most well-documented and consequential aspects of biological ageing — yet it is almost entirely addressable. The science is clear. The tools now exist to restore what time has taken away.

Every year you wait, the decline continues. Every year you act, you are investing in the cellular health that determines how you feel, how you perform, and how you age.

Order your NADvance pen today and begin restoring your NAD+ levels with pharmaceutical-grade precision.