What is NAD+? Effects, benefits, and longevity effects

You may have also noticed that a certain molecule is being reported on more and more often in social media: NAD+.

Stars and celebrities like Hailey Bieber and Kylie Jenner inject it through IV drips, and Harvard professors like David Sinclair compare high NAD+ levels to a fountain of youth.

But what exactly is NAD+ - and what health functions does it perform in the body?

NAD+ stands for nicotinamide adenine dinucleotide – an essential coenzyme found in all our cells and central to energy production .

NAD+ acts in different ways:

• Energy production: NAD+ absorbs electrons, then converts into its reduced form, NADH, and transports the electrons further to release the stored energy. This allows our cells to convert sugar and fat into ATP—our body's primary fuel.
  
  
• Protection & Repair: Without NAD+, important enzymes like PARP wouldn't be able to repair DNA damage, and sirtuins—often referred to as "longevity enzymes"—wouldn't function either. These sirtuins regulate genes, control metabolism, and keep inflammation in check, among other functions.
  
  
• Cell balance: By constantly switching between its active form (NAD+) and NADH, the coenzyme ensures a stable internal balance of the cells and keeps vital processes flowing.
  
  

NAD+ is therefore essential for energy, cell repair, and metabolic regulation . Without this coenzyme, vital processes in the body would not function.

However, with age, this NAD level steadily declines. Research shows that our levels have a significant impact on vitality and healthy cell function .

Scientific studies show that in various tissues the NAD content is significantly lower in old age than in young years.

For example, an analysis of skin samples found that middle-aged adults had over 50% less NAD+ than younger people – in newborns, for example, the levels were several times higher than in adults.

Similar declines have been observed in muscle, brain, liver, and fat tissue. In other words, NAD levels drop rapidly with age.

Scientists therefore argue that this age-related decline in this molecule may be a key driver of the aging process itself. Researchers even refer to the decline in NAD in old age as a potential "Achilles heel" of aging , as it can trigger a cascade of cellular dysfunction.

Why is this? When less NAD+ is available, precisely the processes that require this coenzyme suffer: mitochondria produce less energy (ATP), repair enzymes like PARP are less able to repair DNA damage, and sirtuin activity decreases.

But why do NAD levels decrease with age? Research now has answers to this question. For one thing, this molecule is used up more rapidly with age.

Chronic inflammatory processes , for example, activate an enzyme called CD38 , which degrades NAD+. Studies show that CD38 levels increase significantly, especially in aging tissues.

Likewise, DNA damage increases over the years, which increasingly activates PARP enzymes ; these also consume NAD+ to carry out DNA repair.

Another reason is that the production of this coenzyme becomes less efficient with age, meaning the body produces less of this important molecule.

The higher consumption of NAD+ on the one hand and lower subsequent production on the other hand ultimately leads to a net deficit of this coenzyme.

The consequences of this decline are significant. Studies suggest that the decline in NAD+ is partly responsible for age-related diseases.

Neurodegenerative diseases such as Alzheimer's and Parkinson's, cardiovascular problems including heart failure, but also metabolic disorders such as obesity and diabetes are associated with impaired NAD metabolism.

In other words, low NAD levels could create the breeding ground for many typical age-related diseases, while higher NAD levels have a protective effect.

This finding leads directly to the question of whether age-related damage can be halted or even reversed by replenishing NAD+ stores – a core topic of modern longevity research.

You may now understand the importance of this important molecule for our body. High NAD+ levels apparently promote the "youthfulness" of our cells by maintaining energy balance and repair mechanisms.

Research results on animals are already very promising: If the level of this coenzyme is increased in aging mice using precursors (e.g. NMN or NR), various symptoms of aging can be alleviated.

For example, Imai and Guarente (two renowned age researchers) report that in mouse models, replenishing NAD stores could dramatically improve many age-related functional disorders .

In various studies, increasing this molecule in old animals led to improved metabolic health , fewer inflammatory markers and in some cases even to an extended lifespan .

The activation of the aforementioned sirtuins also plays a role: these longevity enzymes were able to extend lifespan and attenuate age-related diseases in model organisms (yeasts, worms, flies, mice) with sufficient NAD+.

It seems that NAD+ acts as a kind of molecular elixir of life – higher levels of this coenzyme keep the cellular “power plants” running and the cell’s “workshops” intact.

Not all details have been clarified yet, but current data suggest that this important molecule is a key factor in healthy aging .

One example is calorie restriction – consuming fewer calories than is burned – which has been shown to extend the lifespan of a wide variety of organisms.

One possible explanation for this is that calorie restriction increases NAD levels and thereby triggers the protective sirtuin effects.

In other words, fasting mimics an NAD treatment at the cellular level, which improves cellular resilience. This principle is now being exploited in therapies.

Medical researchers are therefore intensively investigating whether NAD+ boosting can also prevent age-related symptoms in humans. Initial small clinical trials are underway or have already been published.

The central question: Can increasing the availability of this important coenzyme in humans improve muscle function, cardiovascular health, cognitive performance or metabolic parameters in old age?

There's no "pill for immortality" yet. But experts are optimistic—they see the combination of sirtuin activation and NAD replenishment as a promising anti-aging intervention for the future.

It can already be said: Maintaining NAD+ means keeping cells young and functional for longer.

We now know that NAD+ is a key molecule for all cells in our body, contributing significantly to our health and performance. We also know that levels of this coenzyme in our body decline dramatically with age. The classic question: How do you raise NAD levels again? There are essentially three options:

As already mentioned, calorie restriction or intermittent fasting can increase NAD+ levels. This happens in two ways:

First, when fasting, less energy is processed from food. As a result, metabolic pathways like glycolysis slow down, and less NAD+ is converted to NADH.

In other words, the consumption of NAD+ decreases, so more of it remains free.

Second, food deprivation activates certain enzymes such as NAMPT , which convert used nicotinamide back into NAD+ in the so-called "salvage pathway." This means the cell produces additional NAD+.

This interaction increases NAD levels. This, in turn, enables important protective enzymes like sirtuins to work more actively—with effects on metabolism, DNA repair, and cell health.

Animal studies show that this mechanism may be a key reason why fasting and calorie restriction slow the aging process.

In addition to nutrition, physical activity plays a particularly important role.

Regular exercise, but especially strength training , acts as a natural NAD+ booster: exercise stimulates the enzyme NAMPT, which converts nicotinamide (a breakdown product of NAD metabolism) back into NAD+.

One study found that 12 weeks of moderate endurance and strength training in older adults increased the amount of the key NAD+ enzyme NAMPT in muscles by ~30% .

This partially offset the age-related decline in muscle tissue. Other studies also confirm that exercise can stabilize NAD+ levels in old age .

A simple and effective way to increase the body's NAD+ levels is to take an NAD+ precursor such as NR or NMN - forms of vitamin B3.

A sufficient supply of vitamin B3 (niacin, nicotinamide) through food forms a basis from which the body can synthesize NAD+.

However, the classic forms of vitamin B3 have their limits in high doses – niacin (nicotinic acid), for example, often causes the unpleasant “flush” (reddening of the skin and a feeling of heat), and very large amounts of nicotinamide can put a strain on the liver.

This is where nicotinamide riboside (NR) comes into play as an NAD+ precursor. NR is present in tiny amounts in our food—for example, in milk, beer, yeast products, and some fruits. However, the true effect can only be achieved through high-dose supplementation.

How does NR work? After ingestion, nicotinamide riboside is converted into NAD+ by the body. More specifically, NR is first phosphorylated to NMN (nicotinamide mononucleotide) and then further synthesized to NAD+.

NR is therefore a direct NAD+ booster that is efficiently absorbed and utilized by our cells.

Compared to other sources of vitamin B3, NR has the advantage of being particularly well tolerated : It does not cause skin reddening like niacin, nor has it shown any significant side effects on the liver or gastrointestinal tract in studies.

Therefore, NR is being researched as a promising longevity nutrient .

Human studies demonstrate that NR significantly increases NAD+ levels. In a placebo-controlled study with healthy older adults (55–79 years), daily intake of NR for 6 weeks increased NAD+ levels in blood cells by approximately 60% .

Also important: The tolerability of NR was very good. In the study mentioned , no serious side effects occurred with NR—in fact, NR was just as well tolerated by participants as the placebo.

Further studies already show that NR has a variety of cell-protective effects : For example, it improves mitochondrial function, reduces oxidative damage and inflammatory reactions, and supports the regeneration of nerve cells.

These properties make nicotinamide riboside one of the most exciting anti-aging agents of recent years.