Understanding the Connection Between NAD+ and Cognitive Function

Many people experiencing persistent brain fog search for ways to improve their mental clarity, concentration and cognitive performance. In recent years, NAD+ (nicotinamide adenine dinucleotide) has attracted growing attention because of its fundamental role in cellular energy production and brain metabolism.

As interest in longevity and preventive medicine has increased, NAD+ therapy has frequently been promoted as a potential solution for symptoms such as brain fog and mental fatigue. However, while scientific research in this area is expanding rapidly, many questions remain unanswered.

This article explores what brain fog is, why researchers are interested in NAD+, and what current medical evidence tells us about the relationship between NAD+ and cognitive function.

What Is Brain Fog?

Brain fog is not a medical diagnosis.

Instead, it is a term commonly used to describe a collection of symptoms affecting mental clarity and cognitive performance.

People experiencing brain fog often report:

• Difficulty concentrating
• Poor memory
• Mental fatigue
• Slower thinking
• Difficulty finding words
• Reduced productivity
• Trouble multitasking
• Feeling mentally "cloudy"

Symptoms may develop gradually or appear suddenly following illness, prolonged stress or significant lifestyle changes.

Because brain fog has many possible causes, identifying the underlying reason is an essential part of effective treatment.

Why Are Researchers Interested in NAD+?

Every thought, memory and decision requires energy.

The human brain represents only around 2% of total body weight, yet it consumes approximately 20% of the body's energy while at rest.

Maintaining this high level of activity requires efficient energy production within brain cells.

Since NAD+ plays a central role in cellular energy metabolism, researchers have become increasingly interested in whether changes in NAD+ availability might influence cognitive function.

This has made NAD+ one of the most actively studied molecules in the fields of neuroscience, ageing and mitochondrial medicine.

How Does the Brain Produce Energy?

Brain cells, known as neurons, require a constant supply of energy to function normally.

Every second, billions of neurons communicate through electrical and chemical signals.

These processes require large amounts of adenosine triphosphate (ATP), the body's primary energy molecule.

ATP is produced mainly inside structures called mitochondria.

To generate ATP efficiently, mitochondria rely on numerous enzymes and coenzymes—including NAD+.

Without sufficient NAD+, these energy-producing reactions cannot proceed normally.

NAD+ and Cellular Energy

NAD+ functions as an essential coenzyme during cellular respiration.

Its primary role is to transport electrons during metabolic reactions that convert nutrients from food into ATP.

Because this process occurs continuously throughout the body, NAD+ is essential for the normal function of almost every cell, including those in the brain.

Researchers believe that maintaining healthy cellular energy metabolism is one reason why NAD+ has attracted attention in studies of cognitive function.

Mitochondria: The Brain's Energy Factories

Mitochondria are often described as the "powerhouses" of the cell.

Within neurons, they provide the energy required for:

• Learning
• Memory formation
• Attention
• Communication between nerve cells
• Cellular repair
• Normal brain function

Because neurons have exceptionally high energy demands, healthy mitochondrial function is essential throughout life.

Scientists are therefore investigating whether changes in mitochondrial function contribute to symptoms affecting cognition and mental performance.

Why Is NAD+ Important for Brain Cells?

Beyond energy production, NAD+ participates in several biological processes that help maintain healthy neurons.

Research suggests NAD+ contributes to:

• Cellular energy metabolism
• DNA repair
• Regulation of oxidative stress
• Mitochondrial function
• Cellular signalling
• Activation of enzymes involved in maintaining normal cellular health

These functions have led researchers to investigate whether altered NAD+ metabolism might influence neurological health.

Can Reduced Cellular Energy Affect Thinking?

Potentially, yes.

The brain depends on a continuous supply of energy.

When normal cellular metabolism is disrupted—whether because of illness, poor sleep, nutritional deficiencies or other medical conditions—some individuals experience symptoms affecting concentration and mental performance.

However, it is important to understand that reduced cognitive performance does not automatically indicate low NAD+ levels.

Many different medical conditions can impair cellular energy production, and researchers continue to study the exact role of NAD+ in this complex process.

Does Age Affect NAD+ Levels?

Research suggests that NAD+ concentrations gradually decline in many tissues with advancing age.

Scientists believe this decline may result from:

• Reduced NAD+ synthesis
• Increased cellular stress
• Greater demand for DNA repair
• Chronic low-grade inflammation
• Increased activity of enzymes that consume NAD+

Whether restoring NAD+ levels can improve cognitive performance in healthy adults remains an important question in current medical research.

Although laboratory findings have been encouraging, definitive clinical evidence is still developing.

Is Brain Fog Caused by Low NAD+?

At present, there is no evidence that brain fog is caused solely by low NAD+ levels.

Brain fog is a symptom with many potential causes, including:

• Iron deficiency
• Vitamin B12 deficiency
• Vitamin D deficiency
• Thyroid disorders
• Sleep disorders
• Chronic stress
• Anxiety
• Depression
• Long COVID
• Hormonal changes
• Certain medications
• Dehydration

For this reason, physicians generally investigate these more common causes before considering emerging therapies.

Why Medical Assessment Matters

Many people searching for information about NAD+ are hoping to find an explanation for persistent cognitive symptoms.

However, assuming that NAD+ is the cause may delay the diagnosis of other treatable medical conditions.

A comprehensive medical assessment allows healthcare professionals to evaluate symptoms in context, review medical history, perform appropriate examinations and recommend targeted laboratory investigations when indicated.

Identifying the underlying cause remains the most important step in managing persistent brain fog.

What Does Current Research Say?

Interest in NAD+ has grown significantly over the past decade, particularly in the fields of neuroscience, ageing and mitochondrial medicine. Researchers are investigating whether maintaining healthy NAD+ levels may support normal cellular function and potentially influence cognitive performance.

Although laboratory research has produced promising findings, the current evidence in humans remains limited. Most experts agree that further high-quality clinical trials are needed before firm conclusions can be drawn.

NAD+ and Cognitive Function

Cognitive function refers to a range of mental abilities, including:

• Attention
• Memory
• Learning
• Executive function
• Decision-making
• Processing speed
• Mental flexibility

These processes depend on healthy neurons receiving a continuous supply of energy. Since NAD+ is essential for mitochondrial ATP production, researchers have explored whether improving NAD+ availability might help support normal brain function.

However, it is important to distinguish between biological plausibility and proven clinical benefit. While NAD+ has an essential role in cellular metabolism, this does not necessarily mean that increasing NAD+ levels will improve symptoms such as brain fog.

What Have Laboratory Studies Found?

Much of the enthusiasm surrounding NAD+ originates from laboratory and animal research.

Experimental studies have suggested that maintaining adequate NAD+ levels may help support:

• Healthy mitochondrial function
• Cellular energy production
• DNA repair mechanisms
• Normal neuronal communication
• Protection against oxidative stress
• Cellular resilience during ageing

Researchers have also observed that increasing NAD+ availability in animal models may improve certain measures of learning and memory.

While these findings are scientifically interesting, results from laboratory research cannot automatically be applied to humans.

Human Clinical Studies

Compared with laboratory research, human studies are still relatively few.

Most published clinical trials have investigated NAD+ precursors—such as nicotinamide riboside (NR) or nicotinamide mononucleotide (NMN)—rather than intravenous NAD+ itself.

These studies have generally focused on:

• Safety
• Changes in blood NAD+ concentrations
• Metabolic health
• Exercise performance
• Healthy ageing

Only a limited number of studies have specifically evaluated cognitive outcomes, and the results have been mixed.

Some participants have reported improvements in subjective wellbeing or energy levels, while others have shown little or no measurable improvement in objective cognitive testing.

Overall, current evidence does not yet demonstrate that NAD+ is an established treatment for brain fog.

NAD+ and Neurodegenerative Disease Research

Scientists are also exploring whether NAD+ may play a role in neurodegenerative conditions such as:

• Alzheimer's disease
• Parkinson's disease
• Amyotrophic lateral sclerosis (ALS)
• Huntington's disease

The rationale stems from the observation that mitochondrial dysfunction, oxidative stress and impaired cellular repair are common features of many neurological disorders.

Although preclinical findings are encouraging, clinical research is still in its early stages, and NAD+ therapies are not currently considered standard treatment for these conditions.

Oxidative Stress and Cellular Repair

Throughout life, cells are exposed to oxidative stress—a natural consequence of metabolism that can damage proteins, DNA and cell membranes.

NAD+ supports several enzymes involved in:

• DNA repair
• Cellular stress responses
• Mitochondrial maintenance
• Cellular survival pathways

Researchers believe these mechanisms may contribute to healthy ageing and normal brain function.

However, the extent to which they influence symptoms such as brain fog in otherwise healthy individuals remains uncertain.

Why Are Results So Variable?

One reason the evidence remains inconclusive is that brain fog is not a single disease.

People with brain fog may have completely different underlying causes.

For example, one person may have:

• Iron deficiency

while another may have:

• Sleep apnoea

and another may be experiencing:

• Chronic stress

Because these conditions affect the brain differently, it is unlikely that one treatment will benefit every individual.

This is why personalised medical assessment remains essential.

Other Common Causes of Brain Fog

Before considering emerging therapies, physicians usually investigate more common medical explanations.

These may include:

Iron Deficiency

Low iron stores can reduce oxygen delivery throughout the body and frequently cause fatigue, reduced concentration and poor cognitive performance.

Vitamin B12 Deficiency

Vitamin B12 is essential for normal neurological function. Deficiency may lead to memory problems, mental slowing and difficulty concentrating.

Thyroid Disorders

Both hypothyroidism and hyperthyroidism can affect mood, cognition and energy levels.

Sleep Disorders

Poor sleep quality, insomnia and obstructive sleep apnoea are among the most common causes of persistent brain fog.

Chronic Stress and Burnout

Long-term stress may impair attention, working memory and executive function through hormonal and neurological mechanisms.

Anxiety and Depression

Mental health conditions often present with cognitive symptoms that improve when the underlying condition is appropriately treated.

Long COVID

Persistent cognitive symptoms have become increasingly recognised following COVID-19 infection, although the exact mechanisms remain under investigation.

Why Blood Tests May Be Recommended

When brain fog persists, laboratory investigations can help identify potentially treatable causes.

Depending on individual symptoms and medical history, a physician may recommend tests such as:

• Full blood count
• Ferritin
• Vitamin B12
• Folate
• Vitamin D
• Thyroid function
• Blood glucose
• HbA1c
• Inflammatory markers
• Electrolytes
• Liver and kidney function

The choice of investigations should always be personalised rather than based on a standard panel for every patient.

Current Medical Consensus

The current scientific consensus can be summarised as follows:

• NAD+ is essential for normal cellular energy production.
• Laboratory research suggests potential neurological benefits.
• Human studies remain limited.
• There is currently insufficient evidence to recommend NAD+ as a proven treatment for brain fog.
• Persistent brain fog should always prompt assessment for underlying medical conditions before considering adjunctive therapies.

As research continues, our understanding of NAD+'s role in cognitive health is likely to evolve. For now, a careful medical evaluation remains the foundation of appropriate care.

Can NAD+ Help People with Brain Fog?

This is one of the most common questions people ask when researching NAD+ therapy.

The honest answer is that we do not yet know.

NAD+ plays an essential role in cellular energy production, mitochondrial function and numerous biological processes that are important for brain health. These findings provide a strong scientific rationale for ongoing research.

However, current clinical evidence is still insufficient to conclude that NAD+ therapy is an effective treatment for brain fog.

Some individuals report improvements in mental clarity, focus or overall wellbeing following NAD+ therapy, but these experiences should be interpreted cautiously. Individual responses can vary considerably, and improvements may also reflect the treatment of other underlying conditions or lifestyle changes occurring at the same time.

Further large, well-designed clinical trials are needed before definitive recommendations can be made.

Who May Benefit from a Medical Assessment?

Persistent brain fog should never be ignored, particularly if symptoms:

• Last for several weeks or months
• Are becoming progressively worse
• Affect work or daily activities
• Occur together with fatigue or memory problems
• Are associated with headaches, dizziness or other neurological symptoms

Rather than focusing on a single therapy, physicians aim to identify the underlying cause of the symptoms.

A comprehensive assessment often provides the most effective pathway towards appropriate treatment.

A Personalised Approach to Care

Because brain fog has many possible causes, management should always be individualised.

Depending on your symptoms and medical history, your physician may recommend:

• A comprehensive medical consultation
• Review of previous laboratory results
• Targeted blood tests
• Assessment of sleep, nutrition and lifestyle
• Evaluation for vitamin or mineral deficiencies
• Hormonal assessment when appropriate
• Review of current medications
• Personalised treatment recommendations

If no underlying medical condition is identified, your physician may discuss whether supportive interventions—including lifestyle optimisation or, in selected cases, therapies such as NAD+—could be appropriate.

Frequently Asked Questions

Is brain fog caused by low NAD+?

Not necessarily.

Brain fog has many possible causes, including nutritional deficiencies, thyroid disorders, sleep problems, chronic stress and certain medical conditions. There is currently no evidence that low NAD+ alone is responsible for brain fog.

Is NAD+ therapy proven to improve cognitive function?

At present, no.

While laboratory research has produced promising findings, current human clinical evidence remains limited. More high-quality studies are needed before NAD+ can be considered an established treatment for cognitive symptoms.

Is NAD+ therapy safe?

When administered under appropriate medical supervision, NAD+ therapy has generally been well tolerated in published studies.

Like any medical treatment, however, it should only be considered after an appropriate medical assessment. Suitability depends on your individual health status, medical history and treatment goals.

Should I have blood tests before considering NAD+ therapy?

In many cases, yes.

Blood tests can help identify common and treatable causes of brain fog, such as iron deficiency, vitamin B12 deficiency, thyroid disorders or metabolic abnormalities. Identifying and treating these conditions should usually take priority.

Can lifestyle changes improve brain fog?

Often, yes.

Improving sleep quality, maintaining a balanced diet, staying physically active, managing stress and addressing underlying medical conditions can all contribute to improved cognitive function.

Key Takeaways

• Brain fog is a symptom rather than a medical diagnosis.
• NAD+ is essential for cellular energy production and healthy mitochondrial function.
• Laboratory research suggests NAD+ may play an important role in maintaining normal brain health.
• Human studies investigating NAD+ and cognitive performance remain limited.
• There is currently insufficient evidence to recommend NAD+ as a proven treatment for brain fog.
• Persistent brain fog should always be medically assessed to identify potentially treatable underlying causes.
• A personalised approach remains the foundation of effective care.

About Dr. Indhira Ghyssaert

Dr. Indhira Ghyssaert is a General Practitioner with a special interest in preventive, integrative and personalised medicine. She provides comprehensive medical assessments designed to identify the underlying causes of symptoms rather than simply treating them in isolation.

At Galatzó Health, Dr. Ghyssaert combines evidence-based medicine with advanced laboratory testing and personalised treatment plans to help patients optimise their health and wellbeing.

Medical Disclaimer

This article is intended for educational purposes only and should not be considered medical advice.

The information provided does not replace an individual medical consultation, diagnosis or treatment. If you are experiencing persistent brain fog, memory difficulties or other concerning neurological symptoms, you should seek assessment from a qualified healthcare professional.

Treatment recommendations should always be based on a comprehensive medical evaluation and your individual clinical circumstances.

Book a Medical Assessment

If you are experiencing persistent brain fog, fatigue or concerns about your cognitive health, a comprehensive medical assessment can help identify potential underlying causes and guide personalised treatment recommendations.

Your consultation may include:

• Comprehensive medical consultation
• Detailed medical history and clinical assessment
• Review of previous laboratory results
• Personalised blood test recommendations
• Individualised treatment recommendations
• Ongoing medical follow-up when appropriate
  
  

Galatzó Health
Mallorca

www.galatzohealth.com

+34 655 726 050

Scientific References

1. National Institute on Aging. NAD+ and Ageing Research.
2. National Institutes of Health (NIH). Nicotinamide Adenine Dinucleotide (NAD+) and Cellular Metabolism.
3. UpToDate. Evaluation of Cognitive Impairment and Brain Fog.
4. NHS. Memory Problems and Cognitive Symptoms.
5. World Health Organization (WHO). Healthy Ageing Framework.
6. Covarrubias AJ, et al. Cell Metabolism. NAD+ metabolism and its roles in cellular processes.
7. Verdin E. Science. NAD+ in ageing, metabolism and neurobiology.
8. Rajman L, Chwalek K, Sinclair DA. Cell Metabolism. Therapeutic potential of NAD+ boosting strategies.