NAD+ Therapy: The science behind cellular energy and what you should know

Remember when pulling an all-nighter meant bouncing back the next day? Now it might take you three days to recover from staying up past 10 PM.

That friend who could eat pizza at midnight without consequence? He’s probably dealing with the same metabolic slowdown you are.

If you’re wondering why your energy feels more like a flickering lightbulb than a steady flame these days, the answer might lie in something called NAD+.

Think of it as your “cellular currency” and like many currencies, it’s been experiencing some serious inflation (or in this case, deflation) over the years.

In this article, we’ll cover everything you need to know about NAD+ and its applications.

What is NAD+ and why should you care?

Nicotinamide adenine dinucleotide (NAD+) sounds intimidating, but it’s actually one of the most important molecules in your body. Every single cell depends on it for basic functions like energy production, DNA repair, and cellular health maintenance.
Here’s a simple way to think about it: if cells were cars, NAD+ would be the fuel. Not just any fuel, but premium grade gasoline that keeps everything running smoothly. As we age, our NAD levels naturally decline (usually starting around age 30-40) and by the time we hit 50, we might have half the NAD+ we had in our twenties.

What does this mean for you? Well, you wouldn’t expect your car to perform the same on half a tank of low-grade fuel, would you? Your body faces the same challenge.

The difference between NAD and NAD+: A quick clarification

You might see both “NAD” and “NAD+” floating around. What’s the difference between NAD and NAD+? They’re essentially the same molecule, but NAD+ refers to the oxidized form. In other words, it’s the version your cells actually use for energy metabolism. When people talk about supplementing with NAD+ or NAD—whether that’s injections or oral supplements—they’re typically referring to NAD+ or its precursors.

Is NAD+ just vitamin B3 then? Not exactly, though they’re related. NAD+ is made from vitamin B3 (also called niacin or nicotinamide), but it’s a much more complex molecule. Vitamin B3 is like the raw material your body uses to build NAD+. Without B3, your NAD levels will continue to drop.

The science behind NAD+: What actually happens in your body

Your mitochondria, the energy producer within each cell, depends on NAD+ for its cellular energy production. When NAD levels drop, it’s like having a generator operating at half capacity. The lights still work, but they’re dimmer.

Beyond energy, NAD+ plays a crucial role in activating proteins called sirtuins, which are involved in DNA repair and healthy aging. Recent human clinical trials have shown that NAD supplementation can actually increase blood NAD levels, suggesting these dietary supplements do reach your cells where they’re needed.

Dr. David Sinclair, a Harvard researcher studying aging, has noted that NAD+ is one of the most important metabolites in the human body which might sound like scientific hyperbole but the clinical evidence is building to support NAD+’s central role in human health.

What the research shows: Separating fact from marketing hype

Obviously, the health and wellness industry loves to promise fountain-of-youth results. So do NAD boosters really work? The answer depends on what you’re looking for and what realistic expectations look like.

Where the evidence is strongest

Physical performance and energy

Multiple randomized controlled trials have shown that NAD precursors can improve exercise capacity in middle-aged and older adults. One study found that those taking nicotinamide mononucleotide (NMN) showed improved muscle insulin sensitivity and better overall energy metabolism.

Cognitive function

While we’re still waiting for large-scale studies, initial evidence suggests NAD+ therapy may support brain health and combat cognitive decline. Some report clearer thinking and better
focus, though individual results vary significantly.

Metabolic function

Clinical trials indicate that adding NAD into your wellness routine may help with insulin resistance and metabolic disorders, particularly in healthy obese humans. The metabolic benefits appear most pronounced in people already dealing with metabolic syndrome.

Where we need more data

The honest truth is that most studies on NAD precursors have been relatively short-term.

While preclinical studies suggest potential benefits for everything from neurodegenerative diseases to skin health, we need longer human clinical trials to understand the full picture.

Muscle function and composition show promise in early studies, but whether these translate to clinically significant improvements in muscle recovery or overall body composition remains to be seen.

What to expect realistically

If you’re hoping that taking NAD+ will turn back the clock 20 years, you’re likely to be disappointed. However, if you’re dealing with age-related fatigue, metabolic slowdown, or declining exercise capacity, the potential benefits might be worth exploring.

Most people who respond well to any NAD supplementation (whether oral or injection) report gradual improvements over 4-8 weeks, though it’s important to note that changes are based on how it is delivered.

Oral supplementation can take longer to have a noticeable impact because it is processed through the digestive track. Injections, meanwhile, bypass this process entirely and can result in faster results.

Who should consider NAD+ therapy?

Prime candidates include:

• Anyone over 40 experiencing noticeable energy decline
• Those dealing with metabolic disorders or insulin resistance
• Active individuals looking to optimize muscle recovery and exercise capacity
• People struggling with brain fog or cognitive decline

The research is particularly strong for healthy adults in middle age who are already experiencing the natural decline in cellular NAD levels.

Who should not take NAD+?

While NAD+ supplementation appears safe for most healthy adults, certain groups should exercise caution:

• People taking medications for diabetes (NAD+ can affect blood sugar)
• Those with a history of cancer (the relationship between NAD+ and cancer cells is still being studied)
• Pregnant or breastfeeding women (insufficient safety data)

Moreover, findings suggest that anyone with a history of liver problems should opt for injections as opposed to oral supplementation to avoid any negative impact on the liver.

Always consult with a healthcare professional before adding any dietary supplement to your routine, especially if you have chronic diseases or take prescription medications.

Safety profile: Is NAD+ safe?

Most clinical trials report minimal side effects regardless of the way it is taken, whether that is oral supplements and injection therapy. The most common complaints are mild stomach upset or sleep disturbances, typically when people first start taking NAD.

Long-term data beyond ~2 years is limited, so periodic re-evaluation should be considered.

How to use NAD+

What is the most effective form of NAD+?

Consistency matters. Most studies use daily dosing over weeks to months. Start low, assess tolerance, and track how you feel over 8–12 weeks.

Routes & expectations

The bottom line: Is NAD really worth taking?

For those experiencing age-related energy decline, metabolic issues, or reduced exercise capacity, NAD+ offers a science-backed approach to supporting healthy aging.

The clinical evidence is strongest for people over 40 who are already noticing the effects of declining NAD stores.

However, NAD+ isn’t a substitute for the fundamentals: a healthy diet, regular exercise, quality sleep, and stress management. Think of it as a potential addition to (but not replacement for) proven lifestyle interventions. If you haven’t addressed diet, exercise, and sleep quality
first, start there.

Practical next steps

Before administering any NAD precursor, we suggest the following course of action:

Discuss with your healthcare professional, especially if you have existing health conditions
Start with a lower dose to assess tolerance
Track your response over 8-12 weeks—energy levels, sleep quality, exercise recovery
Check in with your prescriber every few months, especially if plateaus occur

Your energy doesn’t have to fade quietly

While we can’t stop the age clock, we can support our bodies’ natural repair and energy systems more intelligently.

Augmenting NAD+ levels represents one piece of the healthy aging puzzle backed by real science, not just marketing promises. Whether it’s right for you depends on your individual health status, goals, and how you respond to the fundamentals of healthy living.

The choice to explore adding NAD+ into your healthcare regimen should be an informed one, made in partnership with healthcare professionals who understand your complete health picture.

menMD does not compound medications. Our Pharmacy Partner is a 503A compounding pharmacy and all medications through them require a prescription. This content is educational and not a substitute for personalized medical advice from your healthcare provider.