What Is NAD+ and Why Does It Decline With Age?

NAD+ stands for nicotinamide adenine dinucleotide. Don't worry — we won't make you say that again.

Think of NAD+ as an essential cellular helper.

Every day, your body takes the carbohydrates, fats, and proteins you eat and converts them into energy your cells can use. NAD+ plays an important role in the chemical reactions that make that possible. And that's only part of its job.

NAD+ is involved in processes related to:

• Cellular energy production
• Mitochondrial function
• DNA repair
• Healthy metabolism
• Cellular stress responses
• Normal cellular maintenance

In other words, NAD+ isn't something foreign being introduced to your body. Your body already makes it — and your cells use it every day.

Because virtually everything your body does requires energy at the cellular level. Your brain needs energy. Your muscles need energy. Your organs need energy. Even repairing and maintaining your cells requires energy.

One of the major places that energy is produced is inside structures called mitochondria — often described as the “powerhouses” of your cells. NAD+ helps transfer electrons during the reactions mitochondria use to generate ATP, the primary form of usable cellular energy.

NAD+ isn't caffeine. It doesn't simply “give you energy.” Instead, it helps support the cellular machinery your body naturally uses to produce energy. That's an important difference — and one of the reasons NAD+ has become such an interesting area of wellness and longevity research.

This is where NAD+ gets particularly interesting. Research has shown age-related changes in NAD+ metabolism, with declining NAD+ levels observed in numerous tissues in preclinical research and in some human studies. Scientists believe several processes associated with aging may contribute.

• More cellular stress: Over time, our cells experience accumulated stress and DNA damage. Your body has enzymes dedicated to responding to that damage — and some of those enzymes consume NAD+ while doing their job. More cellular stress can therefore mean greater demand for NAD+.
• More age-related inflammation: Low-grade inflammation tends to increase with age. One enzyme researchers have focused on is CD38, which consumes NAD+. Research suggests increased CD38 activity may be one contributor to age-related changes in NAD+ availability.
• Changes in NAD+ production and recycling: Your body is remarkably efficient. Instead of constantly starting from scratch, it can recycle components to regenerate NAD+ through pathways including the NAD+ salvage pathway. Aging can affect the enzymes and pathways responsible for maintaining this supply.

Put everything together, and the balance can begin to change.

Imagine NAD+ as money moving through a checking account. When demand is balanced, NAD+ that is produced and recycled funds energy metabolism, cellular repair, mitochondrial function, and cellular maintenance — and then gets recycled again.

And that's exactly why researchers have become interested in strategies designed to support NAD+ availability.

Energy gets most of the attention — but NAD+'s role goes much further.

• NAD+ supports cellular repair: Every day, your DNA experiences damage from normal metabolic processes and environmental exposures. Certain enzymes involved in DNA repair — particularly PARPs — depend on NAD+. That connection between NAD+ and cellular maintenance is one reason researchers studying healthy aging have taken such an interest in it.
• NAD+ supports mitochondrial function: NAD+ participates directly in the redox reactions required for mitochondrial energy metabolism. Healthy mitochondrial function is important throughout the body, particularly in tissues with substantial energy requirements such as the brain, heart, and muscles.
• NAD+ supports normal metabolism: NAD+ acts as a coenzyme in metabolic reactions involving carbohydrates, fats, and amino acids. Put simply: NAD+ helps your cells turn the nutrients you consume into something they can actually use.
• NAD+ is connected to healthy aging pathways: NAD+ is required by a group of enzymes known as sirtuins, which are involved in metabolism, stress responses, mitochondrial function, and maintaining cellular health. Because NAD+ availability influences sirtuin activity, researchers have been studying the relationship between NAD+ metabolism and healthy aging for years.

Your body naturally produces NAD+ using compounds derived from vitamin B3 and related precursors. Lifestyle may matter, too — research suggests that exercise, nutrition, circadian rhythm, and metabolic health all interact with NAD+ metabolism.

There are also therapeutic and supplemental approaches designed to increase or support NAD+ availability, including:

• NAD+ injections — physician-prescribed and self-administered at home
• NAD+ IV therapy — administered in a clinic setting
• NAD+ precursors such as NR and NMN

Each approach works differently — and the amount of clinical research behind each one isn't identical. We'll break those differences down separately.

NAD+ has attracted attention because it isn't targeting just one isolated process. It participates in fundamental cellular pathways your body already depends on.

For someone interested in energy metabolism, cellular health, mitochondrial function, recovery, or healthy aging, it's easy to understand why NAD+ has become an increasingly popular topic. And unlike a traditional stimulant, the goal of NAD+ therapy isn't simply to create a temporary “boost.” The idea is to support a molecule already involved in the body's natural cellular energy and maintenance processes.

NAD+ is one of those molecules you probably never thought about — even though your cells have depended on it your entire life. It helps support:

• Cellular energy metabolism
• Mitochondrial function
• DNA repair pathways
• Normal metabolism
• Cellular maintenance

Research has also found that NAD+ metabolism can change as we age, potentially due to increased consumption, inflammation, cellular stress, and changes in the pathways responsible for replenishing NAD+.

That's why supporting NAD+ availability has become such an active area of research — and why NAD+ therapies have attracted growing interest among people looking to take a more proactive approach to wellness and healthy aging.

You can't stop getting older. But understanding what changes inside your cells is a pretty good place to start.