You don’t really think about NMN until it starts going missing, not because it vanishes overnight, but because the things it helps power slowly get harder. Focus takes more effort, recovery drags, energy might feel flatter. And at some point, you wonder if there’s more going on than just “getting older.”
Spoiler: there is. One reason is that your NMN levels are probably lower than they used to be. Let’s take a look at what NMN is, why it matters, and why your body starts making less of it with time.
What is NMN, and why does it matter?
NMN (nicotinamide mononucleotide) is something your body produces naturally. It’s not a new invention or a Silicon Valley biohack, it’s a molecule that exists in you already.
Its main job? Helping your cells produce NAD+, a compound they need to function properly.
NAD+ is involved in:
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Cellular energy production
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DNA repair
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Mitochondrial health
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Muscle function
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Brain performance
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Stress resistance
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And activating sirtuins, proteins linked to longevity
Basically, if your cells had a battery, NAD+ would be the charger, and NMN is what helps keep that charger full.
The problem? Your body doesn’t keep making NMN at the same pace forever.
So… why do NMN levels drop with age?
It’s not one single thing, it’s a few processes piling on over time. Here’s what the research points to:
1. The machinery slows down
Your body makes NMN using enzymes, especially one called NAMPT. Think of NAMPT as the factory worker in charge of NMN production.
As you get older, NAMPT activity declines. That means your body just doesn’t convert vitamin B3 and other raw materials into NMN as efficiently. Production drops. NAD+ starts to fall.
This enzyme slowdown is one of the clearest biological patterns researchers have found when studying ageing.
2. There’s more stress on the system
Ageing brings a rise in something called oxidative stress, essentially an overload of reactive oxygen species that can damage cells and enzymes.
You also get inflammaging: the charming name for low-grade chronic inflammation that creeps in with time.
These two together do a number on the enzymes involved in NMN production and NAD+ recycling. They make it harder to keep up, even if the rest of the system is doing its best.
3. Your cells need more than ever
The older your cells get, the more repairs they need. DNA damage piles up. Mitochondria need help. The immune system works harder. All of this requires NAD+, which means more NMN.
But while demand increases, your body’s ability to supply it decreases. You’re trying to pour from an increasingly empty cup.
4. CD38 gets in the way
Finally, there’s CD38, an enzyme whose main job is to break down NAD+. Under normal conditions, it helps regulate calcium signalling and immune responses. But as we age, CD38 becomes more active and more widespread, especially in inflammatory environments.
That means even if your body is still making some NMN and converting it into NAD+, CD38 is breaking that NAD+ down at a faster rate. You're not just producing less; you're also losing more. The result is a gradual depletion of this key cellular resource, even if your other systems are still trying to keep up.
What does that mean in real life?
A decline in NMN (and NAD+) doesn’t come with a warning label, but the effects are pretty familiar:
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Energy feels lower, even with decent sleep
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Recovery after exercise takes longer
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Muscle strength and endurance dip
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Brain fog becomes more common
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You’re more sensitive to stress
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Skin dulls and healing slows down
Can you do anything about it?
Yes. While we can’t stop NAD+ from declining completely, we can support the systems that produce it, and slow the pace of decline. Here’s what helps:
1. Exercise
Especially resistance training and cardio. Movement is one of the few things that directly boosts NAMPT activity, meaning your body makes more NMN naturally.
It also reduces inflammation and oxidative stress, giving your cells more breathing room.
2. Time-restricted eating or short fasts
Intermittent fasting has been shown to support NAD+ metabolism and reduce the activity of CD38. Even just eating within a 10–12 hour window can activate some of these pathways.
Fasting helps your body prioritise repair, which means less damage and more efficient NAD+ use.
3. Stress management + anti-inflammatory foods
Chronic stress increases inflammation and oxidative damage, which isn’t great for NAD+. Supporting your body with good sleep, regular downtime, and antioxidant-rich foods (think leafy greens, berries, olive oil) can make a real difference.
4. Supplements that make up the gap
As NMN production slows down, supplementing with NMN directly gives your body what it’s struggling to produce.
Clinical studies in humans have shown that NMN supplements can:
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Raise NAD+ levels
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Improve muscle function and endurance
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Support metabolic health
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Enhance focus and recovery
The key is quality: look for a clean, well-dosed product backed by real data, not hype.
Should you start taking NMN?
If you’re over 30 and starting to feel like your energy, focus, or physical performance isn’t what it used to be, supporting your NAD+ production could help. And it’s not just for people chasing longevity records. NMN supports everyday energy, stress resilience, and recovery, all things that matter whether you’re training hard or just trying to stay sharp during the workday.
So, to sum it all up, your NMN levels decline with age because:
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Your body makes less of it
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Your cells need more of it
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And a few sneaky enzymes make the whole process harder
But with the right habits, and the right support, you don’t have to take it lying down. If you want to help your body top up what time takes away, our Ageless NMN is a clean, clinically dosed formula designed to support your natural NAD+ production without fluff, fillers, or caffeine crashes.
