NAD+ has become one of the biggest buzzwords in longevity.

You might have seen it in supplements, podcasts, IV clinics or conversations about energy, mitochondria and healthy ageing.

But NAD+ isn't a new discovery.

Your body has been using it every second of your life.

NAD+ — short for nicotinamide adenine dinucleotide — is a molecule found inside virtually every cell in the body.

It plays an essential role in helping your cells turn nutrients into usable energy, while also participating in processes involved in DNA repair, cellular signalling and maintaining normal cell function.

And researchers have become increasingly interested in what happens to NAD+ metabolism as we get older.

So what exactly does NAD+ do?

Why can its availability change with age?

And does increasing NAD+ actually make us younger?

Let's break it down.

What Exactly Is NAD+?

NAD+ is a naturally occurring coenzyme.

A coenzyme is a molecule that helps enzymes carry out chemical reactions inside your body.

One of NAD+'s most fundamental jobs is helping your cells transfer electrons during metabolism.

In simple terms:

You eat food → your body breaks that food down → NAD+ helps your cells extract and transfer the energy contained within it.

During these reactions, NAD+ can accept electrons and become NADH.

NADH can then give those electrons up again.

This constant cycling between NAD+ and NADH is fundamental to cellular metabolism.

Without it, our cells couldn't efficiently produce the energy needed to function.

But energy production is only part of the story.

NAD+ Does Much More Than Help Produce Energy

Scientists once thought of NAD+ mainly as a molecule involved in metabolism.

We now know it is also used by several important families of enzymes.

These include:

Sirtuins

Sirtuins are proteins involved in regulating numerous cellular processes including metabolism, stress responses and gene regulation.

They require NAD+ to function.

This connection is one of the main reasons NAD+ has attracted so much attention in longevity research.

PARPs

Poly(ADP-ribose) polymerases — usually shortened to PARPs — are enzymes involved in detecting and responding to DNA damage.

They also consume NAD+ as part of their activity.

CD38

CD38 is an enzyme involved in cellular signalling and immune function.

It also breaks down NAD+.

Researchers have become particularly interested in CD38 because its activity can increase with age and inflammation, potentially contributing to changes in NAD+ availability.

This means NAD+ sits at the intersection of several fundamental biological processes:

Energy metabolism
Mitochondrial function
DNA repair
Cellular stress responses
Cell signalling
Gene regulation
Immune function

Which explains why scientists are so interested in it.

So Why Does NAD+ Decline With Age?

This question is more complicated than social media often makes it sound.

Research in animals clearly shows age-related changes in NAD+ metabolism, and reductions in NAD+ have also been observed in some human tissues.

But scientists don't yet have evidence that NAD+ universally falls by the same amount in every tissue of every person as they age.

Human research is still developing.

What researchers do know is that ageing can shift the balance between:

How much NAD+ we make

and

How much NAD+ we use.

Several mechanisms appear to contribute.

1. We May Become Less Efficient at Recycling NAD+

Your body doesn't simply make NAD+ once and throw it away.

It constantly recycles it.

One of the major recycling systems is known as the NAD+ salvage pathway.

An enzyme called NAMPT plays an important role in this process by helping recycle nicotinamide into molecules that can ultimately be converted back into NAD+.

Ageing has been associated in some tissues with changes in NAMPT and NAD+ biosynthesis.

If recycling becomes less efficient while demand remains high, the balance can begin shifting towards lower NAD+ availability.

2. DNA Damage Increases With Age

Every day, the DNA inside our cells is exposed to damage.

Your body has sophisticated systems for detecting and repairing that damage.

But accumulated DNA damage tends to increase with ageing.

Remember those PARP enzymes we mentioned earlier?

When DNA damage occurs, PARPs become active as part of the repair response.

And PARPs consume NAD+.

More DNA damage can therefore mean greater demand on the cellular NAD+ pool.

This doesn't mean DNA repair is a bad thing.

Quite the opposite.

It means NAD+ is one of the resources cells use when responding to damage.

3. Chronic Low-Grade Inflammation Can Increase NAD+ Consumption

Ageing is often accompanied by changes in immune activity and an increase in chronic low-grade inflammatory signalling — sometimes referred to as inflammageing.

One enzyme receiving particular attention here is CD38.

CD38 consumes NAD+, and research suggests its expression and activity can increase in ageing tissues.

More CD38 activity can mean more NAD+ is broken down.

This has led researchers to investigate whether increased NAD+ consumption — rather than simply reduced production — is one of the key reasons NAD+ availability changes with age.

4. Cellular Senescence May Play a Role

As we age, some damaged or stressed cells enter a state called cellular senescence.

These cells stop dividing but don't necessarily disappear.

Senescent cells can release inflammatory signalling molecules that influence surrounding tissues.

This increased inflammatory environment may stimulate NAD+-consuming pathways, including CD38 activity in immune cells.

So ageing can potentially create a cycle:

More cellular stress → more inflammation → greater NAD+ consumption → altered cellular function.

The biology is complex, but this relationship between inflammation, cellular senescence and NAD+ metabolism has become an important area of ageing research.

5. Our Mitochondria Change With Age

You may have heard mitochondria described as the powerhouses of the cell.

They're responsible for producing much of the ATP your cells use as energy.

NAD+ and NADH are deeply involved in this process.

Mitochondrial function changes as we age, while NAD+ metabolism itself differs between cellular compartments.

Researchers are now discovering that the picture may be even more complicated than simply measuring total NAD+ in a tissue.

A cell could potentially have adequate NAD+ overall while certain cellular compartments have altered availability.

This is one reason modern NAD+ research is becoming increasingly focused on where NAD+ is located, not simply how much exists in total.

Does Low NAD+ Make You Feel Tired?

This is where we need to separate biology from marketing.

NAD+ is absolutely essential for energy metabolism.

But feeling tired does not automatically mean you're NAD+ deficient.

Fatigue can be influenced by dozens of factors including:

• Poor sleep

• Iron deficiency

• Low calorie intake

• Stress

• Thyroid problems

• Sleep apnoea

• Illness

• Medication

• Nutrient deficiencies

• Overtraining

• Inadequate recovery

There isn't a standard routine test used to diagnose someone as having “low NAD+” simply because they feel tired.

Think of NAD+ as part of your body's cellular energy machinery rather than an energy stimulant.

It isn't caffeine.

You shouldn't expect NAD+ biology to work like drinking a coffee and suddenly feeling switched on.

Where Does Your Body Get NAD+ From?

Your body has several ways of producing NAD+.

Some of the raw materials come from forms of vitamin B3 and related compounds.

These include:

Niacin — nicotinic acid
Nicotinamide — also called niacinamide
Nicotinamide riboside — NR
Nicotinamide mononucleotide — NMN

Your body can also produce NAD+ through pathways involving the amino acid tryptophan.

Rather than depending entirely on NAD+ from food, your body has sophisticated pathways for creating and recycling it.

Can Lifestyle Influence NAD+?

This is an area where it's easy to overpromise.

NAD+ metabolism is influenced by your overall metabolic state, nutrient availability, cellular activity and circadian biology.

Instead of trying to “hack” one molecule, it makes sense to support the systems involved in healthy cellular metabolism.

That includes the basics we talk about again and again:

Regular exercise
Adequate sleep
A nutrient-dense diet
Maintaining metabolic health
Avoiding smoking
Managing excessive alcohol intake
Supporting a healthy body composition

Exercise in particular influences mitochondrial and metabolic pathways related to NAD+ biology.

But that doesn't mean every workout instantly “boosts NAD+.”

Your metabolism is far more sophisticated than that.

What About NAD+ Supplements?

This is where things become particularly interesting.

Scientists are investigating several methods of increasing NAD+ availability.

Much of the human research has focused on NAD+ precursors, particularly:

NR — nicotinamide riboside

and

NMN — nicotinamide mononucleotide.

These are molecules the body can use within NAD+ biosynthesis pathways.

Human trials have shown that oral NAD+ precursors can increase NAD+-related metabolites and, in some circumstances, NAD+ availability.

But here's the important part:

Increasing NAD+ doesn't automatically mean someone will live longer, have dramatically more energy or reverse ageing.

Clinical outcomes in humans have so far been much less dramatic and more variable than many of the results seen in animal research.

Researchers are still trying to understand:

• Which people may benefit

• Which tissues respond

• The best forms

• Appropriate doses

• How long supplementation should be used

• Whether raising NAD+ translates into meaningful long-term health benefits

A major 2025 review of human evidence concluded that while NAD+ precursor supplementation is biologically promising, clear clinical benefits for healthy ageing remain limited and more research is needed.

What About Taking NAD+ Itself?

You'll also now see supplements containing NAD+ directly rather than using a precursor.

Historically, much more research has focused on NR and NMN than on conventional oral NAD+ itself.

Research into direct oral NAD+ delivery is developing, including newer formulations designed to influence absorption and cellular availability.

However, direct oral NAD+ supplementation currently has a much smaller human evidence base than its popularity might suggest.

This is an emerging field rather than settled science.

What About NAD+ IVs?

NAD+ intravenous infusions have become increasingly popular in longevity and wellness clinics.

The theory sounds straightforward:

Put NAD+ directly into the bloodstream and bypass the digestive system.

But popularity isn't the same thing as clinical evidence.

Human research on intravenous NAD+ remains limited, and there isn't currently robust evidence showing that NAD+ IV therapy slows human ageing or meaningfully extends lifespan.

Does Increasing NAD+ Slow Ageing?

This is probably the biggest question.

And right now the answer is:

We don't know.

Animal research has produced fascinating results.

Increasing NAD+ availability in experimental models has influenced mitochondrial function, metabolism, inflammatory pathways and other processes associated with ageing.

But humans aren't giant mice.

Clinical trials haven't yet shown that taking NAD+, NR or NMN meaningfully extends human lifespan.

Even the idea that NAD+ universally declines throughout the human body with age is more nuanced than it's often presented online.

Some human tissues show age-related declines.

Others haven't been studied well enough to know.

And different individuals may have very different NAD+ metabolism depending on their health, lifestyle, age and tissue being measured.

Why Is NAD+ Research Still So Exciting?

Because NAD+ sits at the centre of so many systems involved in cellular health.

Researchers aren't interested in NAD+ simply because it's trendy.

They're interested because it connects:

Energy production
Metabolism
Mitochondrial function
DNA repair
Cellular stress responses
Inflammation
Gene regulation
Ageing biology

Understanding how NAD+ metabolism changes throughout life may eventually help researchers identify new ways of supporting health during ageing.

But there's an important difference between:

“This pathway is involved in ageing.”

and

“Taking more of this molecule stops ageing.”

We're not at the second statement.

The Bigger Picture

Longevity research can sometimes make ageing sound like one molecule went missing and all we need to do is put it back.

Human biology isn't that simple.

NAD+ is undoubtedly important.

But so are:

Muscle mass.

Cardiovascular fitness.

Sleep.

Blood glucose regulation.

Nutrition.

Hormonal health.

Social connection.

Mental wellbeing.

And hundreds of other biological systems interacting with one another.

NAD+ should be viewed as one fascinating part of the healthy-ageing puzzle, rather than the entire puzzle itself.

The Bottom Line

NAD+ is an essential molecule found inside your cells that plays a fundamental role in energy metabolism, DNA repair, cellular signalling and other processes necessary for life.

Research suggests NAD+ availability and metabolism can change as we age.

Potential reasons include:

Reduced NAD+ production or recycling
Increased DNA damage
Greater PARP activity
Increased CD38 activity
Chronic low-grade inflammation
Cellular senescence
Changes in mitochondrial and metabolic function

Scientists are actively studying whether restoring NAD+ availability could help support aspects of healthy ageing.

But despite the excitement, we don't yet have evidence that simply taking more NAD+ reverses ageing or extends human lifespan.

The research is promising.

The biology is fascinating.

But as with most things in longevity science, the answer is considerably more complex than a single molecule.

And that's exactly why NAD+ is worth watching.

 

NAD+ Supplement Spotlight: Cymbiotika Liposomal NAD+

If you’re looking to support NAD+ levels directly, Cymbiotika Liposomal NAD+ is one option we stock at Essential Remedy Co.

The formula provides 300 mg of NAD+ and uses a liposomal delivery system designed to help protect the ingredients through digestion and support absorption. It also includes complementary ingredients such as TMG, niacin and apigenin, which Cymbiotika includes as part of its broader approach to supporting NAD+ metabolism.

Cymbiotika positions the formula around cellular energy production and healthy ageing, with NAD+ itself playing an important role in normal cellular energy metabolism.

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This article is for general educational purposes only and is not intended to diagnose, treat, cure or prevent any medical condition. Supplements are not a substitute for medical care or a balanced diet. Speak with your healthcare professional before starting a new supplement, particularly if you have a medical condition, take medication, or are pregnant or breastfeeding.