Understanding the Role of NAD+ in Cellular Energy

Fatigue is one of the most common reasons people seek medical advice. While occasional tiredness is a normal response to physical activity, poor sleep or stress, persistent fatigue can significantly affect quality of life and may indicate an underlying medical condition.

In recent years, NAD+ (nicotinamide adenine dinucleotide) has received increasing attention because of its essential role in cellular energy production. As interest in longevity and mitochondrial health has grown, many people have wondered whether NAD+ therapy could help improve energy levels and reduce fatigue.

Although research is advancing rapidly, it is important to understand what is currently supported by scientific evidence and what remains under investigation.

This article explores the relationship between NAD+, fatigue and cellular energy while emphasising the importance of identifying the underlying cause of persistent tiredness.

What Is Fatigue?

Fatigue is more than simply feeling sleepy.

It is a persistent sense of physical, mental or emotional exhaustion that is not always relieved by rest.

People experiencing fatigue often describe:

• Low energy levels
• Lack of motivation
• Difficulty concentrating
• Reduced physical endurance
• Mental exhaustion
• Slower thinking
• Feeling drained despite adequate sleep

Fatigue can develop gradually or appear suddenly following illness, prolonged stress or major life events.

Because fatigue is a symptom rather than a diagnosis, determining its underlying cause is essential.

Physical Fatigue vs Mental Fatigue

Although they frequently occur together, physical and mental fatigue are not identical.

Physical fatigue may present as:

• Muscle weakness
• Reduced exercise tolerance
• Feeling physically exhausted
• Longer recovery after activity

Mental fatigue often includes:

• Difficulty concentrating
• Reduced focus
• Poor memory
• Brain fog
• Decreased productivity

Many medical conditions can contribute to one or both forms of fatigue.

Why Does the Body Need Energy?

Every cell in the body requires energy to function.

Breathing, digestion, muscle contraction, hormone production, immune function and brain activity all depend on a continuous supply of cellular energy.

This energy is stored in the form of adenosine triphosphate (ATP).

Without adequate ATP production, normal cellular function becomes less efficient, which may contribute to feelings of fatigue.

ATP: The Body's Energy Currency

ATP is often described as the body's "energy currency."

Every day, the human body produces and recycles enormous quantities of ATP to sustain life.

ATP powers:

• Muscle movement
• Heart function
• Brain activity
• Cellular repair
• Protein synthesis
• Nervous system function

The production of ATP depends on healthy mitochondria and several essential coenzymes—including NAD+.

What Is NAD+?

NAD+ is a naturally occurring coenzyme found in every living cell.

Its primary role is to facilitate hundreds of metabolic reactions that convert nutrients from food into usable energy.

During cellular respiration, NAD+ transports electrons through a series of biochemical reactions that ultimately generate ATP inside the mitochondria.

Without sufficient NAD+, these reactions cannot proceed efficiently.

Mitochondria: The Cell's Power Stations

Mitochondria are specialised structures found within almost every cell.

Their main function is to produce ATP through oxidative phosphorylation.

Because tissues such as the brain, heart and muscles require large amounts of energy, they contain particularly high numbers of mitochondria.

Researchers have become increasingly interested in mitochondrial health because impaired mitochondrial function has been associated with several chronic diseases and age-related conditions.

Why Has NAD+ Become So Popular?

Interest in NAD+ has expanded rapidly due to research suggesting that NAD+ levels naturally decline with age.

Scientists are investigating whether maintaining healthy NAD+ levels could support:

• Cellular energy production
• Healthy ageing
• DNA repair
• Mitochondrial function
• Cellular resilience
• Metabolic health

This has led to growing public interest in NAD+ supplementation and intravenous NAD+ therapy.

However, scientific enthusiasm should not be confused with established clinical evidence.

Does Low NAD+ Cause Fatigue?

This is currently one of the most important unanswered questions.

NAD+ is unquestionably essential for cellular energy production.

However, there is currently no evidence that low NAD+ is a common or direct cause of fatigue in otherwise healthy individuals.

Fatigue has many possible causes, and most people experiencing persistent tiredness will have explanations unrelated to NAD+ levels.

For this reason, physicians focus first on identifying more common and treatable conditions.

Common Medical Causes of Fatigue

Persistent fatigue may result from a wide variety of medical conditions, including:

• Iron deficiency
• Vitamin B12 deficiency
• Vitamin D deficiency
• Thyroid disorders
• Sleep disorders
• Chronic infections
• Anaemia
• Diabetes
• Chronic stress
• Burnout
• Anxiety
• Depression
• Long COVID
• Certain medications

Because these conditions are common and often treatable, they should usually be investigated before considering emerging therapies.

Why Medical Assessment Is Important

Although many people search for treatments that promise increased energy, fatigue should never be viewed as a diagnosis in itself.

A comprehensive medical assessment allows physicians to:

• Review your symptoms in detail
• Assess your medical history
• Evaluate lifestyle factors
• Identify potential nutritional deficiencies
• Recommend appropriate laboratory testing
• Develop an individualised treatment plan

In many cases, treating the underlying cause is the most effective way to improve energy levels.

What Does Current Research Say?

Interest in NAD+ has grown considerably in recent years, particularly in relation to ageing, mitochondrial health and energy metabolism. Because fatigue is often associated with reduced energy production at the cellular level, researchers have investigated whether increasing NAD+ availability could help improve energy levels.

While the biological rationale is compelling, current clinical evidence remains limited. Most studies have focused on understanding how NAD+ functions within cells rather than demonstrating that NAD+ therapy reliably improves fatigue in people.

NAD+ and Cellular Energy Production

Every cell depends on a continuous supply of ATP to perform its normal functions.

NAD+ plays an essential role in the metabolic pathways that generate ATP from carbohydrates, fats and proteins.

As a coenzyme, NAD+ helps transfer electrons through the mitochondrial respiratory chain, allowing cells to produce energy efficiently.

Because this process occurs in every organ—including the brain, muscles and heart—researchers believe maintaining healthy NAD+ levels is important for overall cellular function.

Mitochondrial Function and Fatigue

Mitochondria are responsible for producing most of the body's energy.

When mitochondrial function becomes impaired, cells may produce energy less efficiently.

Scientists have observed mitochondrial dysfunction in several conditions associated with fatigue, including:

• Chronic illnesses
• Age-related diseases
• Certain neurological disorders
• Some metabolic conditions

This has led researchers to investigate whether supporting mitochondrial health could help improve symptoms in selected patients.

However, mitochondrial dysfunction is only one possible contributor to fatigue and is not present in every individual experiencing tiredness.

What Do Human Studies Show?

Human research on NAD+ and fatigue is still in its early stages.

Most published clinical studies have investigated:

• Safety
• Pharmacology
• Blood NAD+ concentrations
• Metabolic health
• Exercise performance
• Healthy ageing

Only a small number of studies have specifically evaluated fatigue as a primary outcome.

Some participants have reported improvements in perceived energy and wellbeing, while others have shown little or no measurable benefit.

At present, there is insufficient high-quality evidence to conclude that NAD+ therapy consistently improves fatigue.

NAD+ and Chronic Fatigue

Persistent fatigue can occur in many different medical conditions.

Researchers have explored whether therapies targeting cellular metabolism might eventually benefit people with chronic fatigue syndromes or prolonged post-viral fatigue.

Although this area remains scientifically interesting, current evidence is still preliminary.

NAD+ therapy is not currently considered a standard treatment for chronic fatigue syndrome (ME/CFS) or other chronic fatigue disorders.

Further well-designed clinical trials are needed to determine whether specific groups of patients may benefit.

Ageing, NAD+ and Energy

One reason NAD+ has attracted attention is that its levels appear to decline gradually with age in many tissues.

Researchers believe this decline may contribute to changes in:

• Cellular repair
• Mitochondrial efficiency
• Metabolic function
• Muscle performance
• Recovery from physiological stress

Whether restoring NAD+ levels can meaningfully improve energy levels in healthy adults remains an active area of investigation.

Current evidence is encouraging but not yet definitive.

Why Results Differ Between Individuals

Fatigue is one of the most complex symptoms encountered in medicine.

Two people may experience similar levels of tiredness while having completely different underlying causes.

For example, fatigue may result from:

• Anaemia
• Poor sleep
• Thyroid disease
• Depression
• Nutritional deficiencies
• Chronic inflammation
• Viral illness
• Medication side effects

Because the underlying mechanism varies from person to person, no single treatment is likely to be effective for everyone.

This highlights the importance of personalised medical care.

Common Causes of Fatigue That Should Be Investigated

Before considering therapies such as NAD+, physicians usually assess for more common and potentially treatable causes of fatigue.

These include:

Iron Deficiency

One of the leading causes of persistent fatigue worldwide, particularly in women of reproductive age.

Vitamin B12 Deficiency

Can lead to tiredness, weakness and neurological symptoms, including difficulty concentrating.

Vitamin D Deficiency

Low vitamin D levels have been associated with fatigue in some individuals, although symptoms vary considerably.

Thyroid Disorders

An underactive thyroid (hypothyroidism) commonly causes fatigue, reduced exercise tolerance and weight changes.

Sleep Disorders

Insomnia and obstructive sleep apnoea are frequent but often overlooked causes of daytime tiredness.

Chronic Stress and Burnout

Long-term psychological stress can affect sleep, hormone regulation and perceived energy levels.

Depression and Anxiety

Mental health conditions frequently present with persistent fatigue and low motivation.

Why Blood Tests May Be Recommended

A physician may recommend laboratory investigations to identify possible medical explanations for fatigue.

Depending on your symptoms and clinical history, these may include:

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

The choice of tests should always be guided by your individual clinical presentation rather than a routine screening panel.

Current Medical Consensus

The current scientific evidence suggests:

• NAD+ is essential for normal cellular energy production.
• Mitochondrial function plays an important role in overall energy metabolism.
• Laboratory studies provide promising insights into the biological role of NAD+.
• Human clinical evidence remains limited.
• There is currently insufficient evidence to recommend NAD+ as a proven treatment for fatigue.
• Persistent fatigue should always prompt assessment for underlying medical conditions before considering adjunctive therapies.

As research continues to evolve, our understanding of NAD+'s role in fatigue may become clearer. For now, careful medical evaluation remains the cornerstone of appropriate management.

Can NAD+ Improve Energy Levels?

One of the main reasons people seek information about NAD+ therapy is the hope of increasing energy and reducing persistent fatigue.

From a scientific perspective, the answer is nuanced.

NAD+ is essential for cellular energy production and healthy mitochondrial function. Because of this, researchers believe that maintaining adequate NAD+ levels may support normal metabolic processes. However, there is currently insufficient clinical evidence to conclude that NAD+ therapy is an effective treatment for fatigue in the general population.

Some individuals report improvements in energy, wellbeing or recovery following NAD+ therapy, but these experiences vary considerably. Fatigue is a complex symptom with many potential causes, and no single treatment is appropriate for everyone.

Further high-quality clinical trials are needed to determine which patients, if any, are most likely to benefit.

The Importance of Identifying the Underlying Cause

Treating fatigue successfully begins with understanding why it has developed.

Many underlying conditions can cause persistent tiredness, and addressing these often leads to significant improvement without the need for additional therapies.

Depending on your symptoms, your physician may investigate:

• Nutritional deficiencies
• Hormonal imbalances
• Sleep disorders
• Chronic infections
• Metabolic conditions
• Mental health
• Lifestyle factors
• Medication side effects

This personalised approach helps ensure that treatment is directed at the underlying problem rather than simply managing symptoms.

When Might NAD+ Be Considered?

Following a comprehensive medical assessment, some patients may discuss NAD+ therapy as part of a broader personalised health plan.

This may be considered alongside other evidence-based strategies such as:

• Optimising sleep quality
• Improving nutrition
• Correcting vitamin or mineral deficiencies
• Increasing physical activity where appropriate
• Managing stress effectively
• Treating identified medical conditions

NAD+ should not be viewed as a substitute for diagnosing and treating underlying causes of fatigue.

Frequently Asked Questions

Is fatigue caused by low NAD+?

Not necessarily.

While NAD+ is essential for cellular energy production, there is currently no evidence that low NAD+ is a common cause of fatigue in otherwise healthy individuals.

Can NAD+ therapy increase energy?

Some individuals report feeling more energetic after NAD+ therapy, but current scientific evidence remains limited.

More high-quality clinical studies are needed before NAD+ can be recommended as an established treatment for fatigue.

Should I have blood tests before considering NAD+ therapy?

In many cases, yes.

Blood tests can identify common and treatable causes of fatigue, including iron deficiency, vitamin B12 deficiency, thyroid disorders, diabetes and other metabolic abnormalities.

Addressing these conditions should usually be the first priority.

Is NAD+ therapy safe?

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

However, like any medical treatment, suitability should be determined following an individual medical assessment.

Can lifestyle changes improve fatigue?

Yes.

Many people experience significant improvements in energy levels by:

• Improving sleep habits
• Eating a balanced diet
• Staying physically active
• Managing stress
• Treating nutritional deficiencies
• Addressing underlying medical conditions

Lifestyle measures often form an important part of a comprehensive treatment plan.

Key Takeaways

• Fatigue is a symptom rather than a medical diagnosis.
• NAD+ plays an essential role in cellular energy production and mitochondrial function.
• Laboratory research suggests a potential role for NAD+ in supporting healthy cellular metabolism.
• Human clinical evidence remains limited.
• There is currently insufficient evidence to recommend NAD+ as a proven treatment for fatigue.
• Persistent fatigue should always be medically assessed to identify potentially treatable underlying causes.
• A personalised approach remains the cornerstone 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 fatigue or unexplained low energy levels, 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 fatigue or reduced energy levels, 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. Approach to the Adult with Fatigue.
4. National Institute for Health and Care Excellence (NICE). Fatigue in Adults: Assessment and Management.
5. NHS. Fatigue (Tiredness).
6. Covarrubias AJ, et al. Cell Metabolism. NAD+ metabolism and its roles in cellular processes.
7. Verdin E. Science. NAD+, metabolism and healthy ageing.
8. Rajman L, Chwalek K, Sinclair DA. Cell Metabolism. Therapeutic potential of NAD+ boosting strategies.