Does Fasting Really Increase NAD+?

You've probably heard claims that fasting can boost your NAD+ levels—a molecule that's been getting a lot of attention in the longevity and wellness space. But does fasting actually increase NAD+, or is this another overhyped health trend?

NAD+ (nicotinamide adenine dinucleotide) plays essential roles in energy production, DNA repair, and cellular health. As we age, NAD+ levels naturally decline, which has led researchers to explore ways to maintain or boost these levels.

Here's what the science actually says about fasting and NAD+.

Key takeaways

• Research in animals suggests fasting may increase NAD+ levels, but studies in humans are limited and the evidence is still unclear.

• Fasting appears to activate certain pathways related to NAD+ production, though we don't know how much fasting is needed or which methods work best in people.

• NAD+ levels are influenced by many factors including exercise, diet, sleep, and stress—not just fasting—so a holistic approach to health is important.

What is NAD+ and why does it matter?

NAD+ is a coenzyme found in every cell of your body. It plays important roles in converting food into energy, supporting DNA repair, regulating your sleep-wake cycle, and helping certain proteins function properly.

Your NAD+ levels naturally decline as you get older. By middle age, you may have about half the NAD+ you had in your youth. This decline has sparked interest in finding ways to support healthy NAD+ levels.

The theory: How fasting might affect NAD+

The idea that fasting could increase NAD+ is based on several biological processes.

Activating helpful enzymes

When you fast, your body may increase production of an enzyme called NAMPT. This enzyme is important for one of the main ways your body makes NAD+.

Research in animals suggests that eating fewer calories and fasting can boost NAMPT activity, which could lead to higher NAD+ levels.

Reducing NAD+ use

Your body constantly uses NAD+ for various processes. Some enzymes consume a lot of NAD+. Studies suggest that fasting might reduce how much these enzymes use, helping preserve your NAD+ stores.

Activating longevity proteins

Sirtuins are proteins that play roles in cellular health and aging. They need NAD+ to function, and they appear to be more active during fasting.

When sirtuins are activated, they may trigger changes that support NAD+ production.

Changing how you burn energy

Fasting causes your body to shift from using sugar as its main fuel to using fat. This change in how your cells produce and use energy may influence NAD+ levels.

What does the research actually show?

While these mechanisms sound promising, we need to look at what studies have actually found.

Studies in animals

Most evidence for fasting increasing NAD+ comes from research in mice and other animals.

Eating less overall: Multiple studies in rodents have found that eating 20-40% fewer calories than normal leads to increased NAD+ levels in muscle, liver, and brain.

Eating only during certain hours: Research in mice that eat only during specific hours has shown increases in NAD+ levels and better metabolic health markers.

Fasting on and off: Some animal studies on intermittent fasting have reported higher NAD+ levels along with better energy production in cells.

These animal studies are helpful for understanding basic biology, but animals and humans don't always respond the same way to dietary changes.

Studies in humans

The evidence in people is much more limited.

Small studies show possibilities: A few small studies have found that eating fewer calories or following fasting schedules may influence markers related to NAD+ in humans. However, directly measuring NAD+ levels is less common.

Measurement difficulties: It's hard to measure NAD+ levels accurately in living people. Most studies measure NAD+ in blood cells, but this may not reflect what's happening in other parts of your body like muscle or brain.

People respond differently: The limited research in humans suggests that responses to fasting vary between people based on age, sex, overall health, and genetics.

What we still don't know

Several important questions remain unanswered:

• How much fasting might be needed to increase NAD+ in humans?

• Which fasting methods work best?

• Do increases in NAD+ actually lead to health benefits?

• How long do any increases last?

• Do effects differ based on age, sex, or health status?

Until we have more human research, we can't say definitively that fasting increases NAD+ in people or that any increases matter for health.

Types of fasting and potential effects

Different fasting approaches may have different effects on NAD+.

Intermittent fasting (16:8 or 18:6)

This involves eating within a specific window each day—like 8 or 6 hours—and not eating during the remaining hours.

What we know: Some animal research suggests this pattern may support NAD+ levels, but human data is limited. The metabolic changes that occur after 12-16 hours without eating may be when some NAD+-related changes begin.

Alternate-day fasting

This involves alternating between regular eating days and fasting or very low-calorie days.

What we know: Animal studies on alternate-day fasting have shown increases in NAD+. Human studies are limited but suggest metabolic changes that could theoretically affect NAD+ levels.

Longer fasting periods (24-72 hours)

Extended fasting creates bigger metabolic shifts.

What we know: Longer fasting clearly activates many pathways associated with NAD+ in animal studies. However, extended fasting isn't sustainable long-term and may carry more risks.

Simply eating less (without specific fasting times)

Eating fewer calories overall, regardless of when you eat.

What we know: This is the most studied approach in animals and has consistently shown increases in NAD+ levels. Some human studies on eating fewer calories have found metabolic changes that suggest changes in NAD+, though direct evidence is limited.

Other factors that influence NAD+ levels

Fasting isn't the only thing that affects your NAD+ levels.

Exercise

Physical activity, especially intense exercise, appears to support NAD+ production. Some research suggests exercise may be as important as dietary changes for NAD+ levels.

What you eat

Your diet matters beyond just calories. Foods rich in nutrients your body needs to make NAD+—like niacin (vitamin B3) and the amino acid tryptophan—can support NAD+ production.

Sleep

Poor sleep or irregular sleep patterns can negatively affect NAD+ levels. NAD+ follows a daily rhythm, with levels changing throughout the day and night.

Stress

Chronic stress and inflammation can use up NAD+ by increasing enzymes that consume it.

Age

NAD+ naturally declines with age, and this decline may be harder to influence through lifestyle changes alone as you get older.

NAD+ supplements vs. fasting

Given the uncertainty around fasting and NAD+, some people turn to supplements.

NAD+ building blocks

Supplements like nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN) are compounds your body can convert to NAD+. Research suggests these supplements can increase NAD+ levels in the blood, though questions remain about optimal amounts and long-term effects.

Direct NAD+ in a stable form

Some people opt for liposomal NAD+ directly to support their NAD+ levels.

Combining approaches

Some researchers think that combining fasting with NAD+ supplements might work better than either alone, though this hasn't been thoroughly studied in humans.

Practical considerations if you're interested in trying fasting

If you're thinking about trying fasting, here are some things to keep in mind.

Start slowly

If you're new to fasting, start with a moderate approach like 12-14 hours overnight (which might just mean finishing dinner by 7 PM and not eating breakfast until 9 AM). You can gradually extend the fasting window if it feels comfortable.

Prioritize overall health

Fasting isn't right for everyone. Talk to your healthcare provider before starting any fasting routine, especially if you have diabetes or blood sugar issues, take medications, have a history of eating disorders, are pregnant or breastfeeding, or have chronic health conditions.

Focus on food quality

When you do eat, choose nutrient-dense whole foods that provide NAD+ building blocks:

• Niacin (vitamin B3): found in meat, fish, peanuts, and mushrooms

• Tryptophan: found in turkey, eggs, cheese, and nuts

• General nutrition: vegetables, fruits, whole grains, lean proteins, and healthy fats

Don't forget other healthy habits

Remember that sleep, exercise, stress management, and overall diet quality all influence NAD+. Fasting alone—if it even works in humans—isn't a complete solution.

Keep realistic expectations

Even if fasting does increase NAD+ levels somewhat, we don't yet know if this leads to meaningful health improvements in people.

Who should avoid or be cautious about fasting?

Fasting isn't appropriate for everyone.

Talk to your doctor before fasting if you:

• Have diabetes or blood sugar issues

• Are pregnant or breastfeeding

• Have a history of eating disorders

• Are underweight or have nutrient deficiencies

• Take medications that need to be taken with food

• Are under 18 years old

• Have chronic health conditions

Even for healthy adults, very restrictive fasting can lead to nutrient deficiencies, muscle loss, hormonal changes (especially in women), tiredness and difficulty concentrating, and challenges with social eating.

The bottom line

So does fasting really increase NAD+? The honest answer is: it might, but we're not sure—at least not in humans.

Animal research strongly suggests that eating fewer calories and various fasting patterns can increase NAD+ levels. The science behind how this might work makes sense.

However, we don't have enough high-quality studies in humans that directly measure NAD+ levels in response to different fasting methods. The studies we do have suggest that fasting influences NAD+-related processes, but we don't know how much this matters for health.

If you're interested in potentially supporting your NAD+ levels through lifestyle changes, consider:

• Moderate time-restricted eating (like 12-16 hours of overnight fasting)

• Regular physical activity

• Good sleep habits

• A nutrient-dense diet

• Stress management

• A good quality liposomal NAD+ supplement or NAD+ precursors 

But remember: focusing on one molecule or one intervention isn't as important as your overall lifestyle. The best approach is to build healthy habits that support your wellbeing in many ways.

And as always, talk with your healthcare provider before making significant changes to your eating patterns, especially if you have any health conditions or take medications. They can help you determine what's safe and appropriate for your individual situation.

 

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Consult with a healthcare provider before starting any magnesium supplement, especially if you have kidney disease, heart conditions, or take medications that interact with magnesium.