You've probably heard it a million times: "Your metabolism slows down as you age."
And if you're over 40, you've likely felt it. The weight that used to come off easily now sticks around. You're eating the same, moving the same, but your body responds differently. So you cut calories, add more cardio, maybe even try intermittent fasting.
Sometimes it helps. Often, it doesn't.
That's because the story we've been told about metabolism - that it's all about calories in versus calories out, or that it's purely hormonal - is incomplete. There's a deeper layer to metabolic function that most people never hear about: cellular energy production.
Your metabolism isn't just about how many calories you burn. It's about how efficiently your cells can actually produce and use energy (and how you can support them). And that efficiency? It declines with age for reasons that have nothing to do with your diet or exercise routine.
What Actually Drives Metabolism
When we talk about metabolism and calories, we're really talking about the sum of all chemical reactions happening in your body. Breaking down food. Building new cells. Repairing damage. Moving. Thinking. Breathing. All of it requires energy.
That energy comes from your mitochondria, the tiny powerhouses inside your cells that convert nutrients into ATP (adenosine triphosphate), the energy currency your body actually uses.
You have trillions of mitochondria spread across your body, and they're working constantly. Your heart cells are packed with them. So are your brain cells, your muscles, your liver. Any tissue that needs a lot of energy has a lot of mitochondria.
But the problem is that mitochondrial function declines as you age. Your mitochondria become less efficient at producing ATP. Some die off entirely. Others accumulate damage and don't work as well as they used to.
When your cells can't produce energy efficiently, everything slows down. Your metabolism included.
The NAD+ Decline
At the centre of this decline is a molecule called NAD+ (nicotinamide adenine dinucleotide). NAD+ is a coenzyme found in every cell of your body, and it's absolutely essential for energy production. Your mitochondria need NAD+ to convert the food you eat into usable energy.
But NAD+ levels drop significantly as you age. By the time you're 50, you might have half the NAD+ you had at 20. By 80, it could be even lower.
Lower NAD+ means less efficient energy production. Less efficient energy production means slower metabolism, less cellular repair, more oxidative stress, and accelerated ageing at the cellular level.
You can eat perfectly and exercise consistently, but if your cells can't produce energy efficiently, your metabolism will still feel sluggish.
It's Not Just About Weight
The metabolic slowdown that comes with declining NAD+ and mitochondrial function affects far more than your waistline.
Low cellular energy impacts:
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Cognitive function: your brain is an energy hog, and when cellular energy drops, so does mental clarity
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Physical performance: muscles need ATP to contract, and inefficient energy production means less stamina and slower recovery
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Cellular repair: fixing daily damage requires energy, and without it, cells age faster
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Sleep quality: your circadian rhythm depends on NAD+, and disrupted sleep further tanks your metabolism
This is why metabolic decline doesn't just mean weight gain. It means fatigue, brain fog, poor recovery, disrupted sleep, and an overall sense that your body isn't keeping up the way it used to.
Enter NMN
So if declining NAD+ is at the root of metabolic slowdown, the logical question is: can you increase it?
The answer is yes, but not by taking NAD+ directly. NAD+ is a large molecule that doesn't absorb well when taken orally. Your body needs to build it from precursors.
NMN (nicotinamide mononucleotide) is one of those precursors. It's a direct building block for NAD+, and research suggests it efficiently converts to NAD+ once absorbed.
By supplementing with NMN, you're giving your body the raw materials to restore NAD+ levels and, in turn, support mitochondrial function and cellular energy production.
This is not a metabolism "booster" in the traditional sense. It's supporting the fundamental process your cells use to produce energy in the first place.
What Else Supports Metabolic Function?
NMN addresses a fundamental aspect of metabolic decline, but it's not the only factor. Supporting healthy metabolism as you age is multifaceted.
Strength training: Muscle is metabolically active tissue. The more you have, the higher your resting metabolic rate. Resistance training also supports mitochondrial health.
Protein intake: Adequate protein supports muscle maintenance, has a higher thermic effect than carbs or fats, and helps prevent the muscle loss that often accompanies ageing.
Sleep quality: Poor sleep disrupts hormones, increases inflammation, and impairs mitochondrial function. NAD+ also plays a role in circadian rhythm regulation, so supporting NAD+ levels may help with sleep quality too.
Managing stress: Chronic stress drives cortisol, which can impair metabolism and accelerate cellular ageing. Stress management isn't optional if you want your metabolism to function optimally.
Nutrient density: Micronutrients like B vitamins, magnesium, and CoQ10 all play roles in energy production. A varied, nutrient-dense diet supports the entire metabolic machinery.
Why Ageless NMN?
NMN isn't new to the longevity space, but not all NMN is created equal. Purity, bioavailability, and dosage matter.
Ageless NMN was formulated with these factors front and centre. Each serving provides 1000mg of pharmaceutical-grade NMN, a clinically relevant dose based on emerging research.
What makes Ageless NMN different?
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High purity – third-party tested to ensure you're getting actual NMN, not degraded or contaminated product
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Optimal dosage – 1000mg is within the range used in human studies showing benefits for NAD+ levels and metabolic markers
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Bioavailable form – designed for efficient absorption so your body can actually use it
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No unnecessary fillers – clean formulation focused on efficacy, not marketing fluff
The goal isn't just to boost NAD+ temporarily. It's to support sustained cellular energy production, which has downstream effects on metabolism, cognitive function, physical performance, and overall vitality.
People who take Ageless NMN consistently often report improved energy levels, better mental clarity, enhanced exercise recovery, and an overall sense of their body "working better" – not through stimulation, but through restored cellular function.
