The Truth About NAD+ and Longevity, What Marketers Won’t Tell You (and What the Research Actually Shows)

How a Molecule Nobody Talked About Became a “Fountain of Youth”

It happened quietly at first, a podcast mention here, a celebrity Instagram story there. Then suddenly, wellness clinics from Los Angeles to London were advertising NAD+ infusions as the ultimate anti-aging hack. Hailey Bieber does it. Kendall Roy from Succession probably would too, if he thought it would help him live long enough to take over the company.

The marketing is undeniably compelling: Boost your NAD+ levels. Repair your DNA. Turn back the clock. Pills, powders, IV drips, there’s a delivery method for every budget and comfort level.

But here’s the question nobody seems to be asking loudly enough: Does any of it actually work? Like, really work, in humans, not just in lab mice who also run marathons on the weekend and eat a perfectly controlled diet?

I wanted to find out. Not so I could sell you something, but so you can make a decision with your eyes wide open.

---

What Is NAD+? (And Why Should You Care?)

Let’s start with the basics, because NAD+ is genuinely fascinating, and it deserves to be understood before we get into whether you should pay hundreds of dollars to have it dripped into your arm.

NAD+ stands for nicotinamide adenine dinucleotide. (Try saying that five times fast, or just stick with “NAD+.”) It’s a coenzyme found in every single living cell of your body.

Think of NAD+ as the middleman in your cellular energy factory. When you eat food, NAD+ helps shuttle electrons around so your mitochondria, the tiny power plants inside your cells, can produce ATP, which is essentially your body’s fuel currency. Without NAD+, your cells can’t make energy. You die. Quickly. (See? I told you it was important.)

But NAD+ does more than just energy. It also acts as a helper for two crucial families of enzymes:

1. Sirtuins , often called “longevity proteins” because they regulate stress resistance, metabolism, and inflammation.
2. PARPs , enzymes that repair damaged DNA.

Here’s the problem: NAD+ levels naturally decline with age , by some estimates, as much as 50% between your 20s and your 60s. And that decline happens to coincide with many of the things we associate with getting older: fatigue, slower metabolism, cognitive fog, and increased vulnerability to chronic disease.

So the logic that launched a thousand supplement bottles goes like this: If NAD+ drops with age, and NAD+ is essential for energy and repair, then topping it back up should slow or even reverse aging, right?

It’s an elegant theory. But elegant theories have a way of getting messier when you actually test them in humans.

---

The Longevity Theory: Why NAD+ Became an Anti-Aging Obsession

Before we dig into the evidence, it helps to understand why scientists got excited in the first place, because it wasn’t just marketers making things up.

The early research was genuinely promising. In yeast cells, worms, and mice, boosting NAD+ activity, particularly through sirtuin activation, extended lifespan and improved markers of health. MIT biologist Leonard Guarente, one of the pioneers of sirtuin research, found that genes like SIR2 (which require NAD+ to function) could make yeast live longer, and when similar effects were observed in roundworms, the excitement spilled over into mammalian research.

Then came the mouse studies: In aged mice, supplementing with NAD+ precursors like nicotinamide riboside (NR) or nicotinamide mononucleotide (NMN) improved glucose regulation, mitochondrial function, endurance, and even cognitive performance. One widely cited mouse study showed that boosting NAD+ extended median lifespan by up to 10%.

By the mid-2010s, supplement companies and wellness clinics were off to the races. The leap from “aging mice ran faster on a treadmill” to “you should pay $800 for an IV drip” happened faster than you can say placebo effect.

---

What the Science Actually Says About NAD+ and Longevity

Now we’re in the part of the conversation where we have to say the uncomfortable thing out loud: most of what you’ve heard about NAD+ and human longevity is extrapolation, not evidence.

NAD+ Precursors (NMN & NR): Where the Best Human Data Lives

If any part of the NAD+ conversation deserves cautious optimism, it’s this one.

Rather than taking NAD+ directly, which is essentially useless orally because the molecule gets destroyed in your stomach, most credible supplements deliver precursors like nicotinamide riboside (NR) or nicotinamide mononucleotide (NMN). Your body converts these into NAD+ through its own biosynthetic pathways.

The good news: multiple human clinical trials have now demonstrated that oral NR and NMN reliably raise NAD+ levels in blood , sometimes by 50–100%, and are generally well-tolerated. A 2025 PRISMA-guided systematic review that analyzed 113 studies (33 human, 80 rodent) confirmed this: oral NR and NMN “consistently demonstrated biochemical target engagement.”

The less-good news: raising blood NAD+ is not the same as improving health or extending lifespan. The same systematic review found that effects on functional, metabolic, and vascular outcomes in humans were “heterogeneous and often null or endpoint-specific.” In plain English: some studies found small improvements in things like insulin sensitivity or arterial stiffness; others found nothing meaningful.

A 2025 study published in Cell Metabolism even challenged the foundational premise, researchers depleted NAD+ levels in mouse muscle cells by 85% and found no acceleration of aging or impairment of metabolism. As one of the researchers put it: “Our data suggests [NAD+ decline] may be an aging marker, but it’s certainly not a driver of aging, at least not in muscle.”

That doesn’t mean NAD+ precursors are worthless. A pilot study of Qualia NAD+ in 63 healthy adults showed a 67% average increase in NAD+ levels and some improvements in emotional well-being and vitality, but notably, significant anti-aging symptom improvements were only found in females, not males. Meanwhile, a 2024 trial in middle-aged Japanese men found NMN was safe and modestly improved post-meal insulin markers, in a grand total of 3 participants.

So where does that leave us? NAD+ precursors can raise NAD+ levels in your blood. Whether that translates into living longer, healthier, or better, the evidence is thin, inconsistent, and far from settled.

NAD+ Infusions & Injections: High Cost, Thin Evidence

This is where things get uncomfortable, especially if you’ve already spent money on it.

NAD+ IV therapy is booming. Wellness clinics charge anywhere from $200 to $2,000 per session, and packages for full treatment series can run $6,000 to $17,000. The pitch is that IV delivery bypasses digestion and floods your cells with NAD+ directly, fast, potent, transformative.

The problem: there are essentially no randomized controlled trials testing IV NAD+ for anti-aging or wellness in humans. A 2025 systematic review that specifically looked for such studies found “no eligible outcomes trials” evaluating intravenous NAD+ for anti-aging.

What about the safety of these infusions? One pilot study that compared NAD+ IV with NR IV in healthy adults reported that NAD+ IV recipients experienced moderate to severe gastrointestinal symptoms, increased heart rate, and chest pressure during the infusion. Other anecdotal reports include dizziness, nausea, and anxiety during treatment.

And critically: NAD+ infusions are not FDA-approved for any anti-aging or wellness indication. They are used off-label, in unregulated settings, sometimes prepared under conditions the FDA has explicitly warned about.

If you’re paying $800 to feel nauseous for an hour in the hope that it might, maybe, slow your aging based on zero human longevity data, you should at least know that’s what you’re doing.

The Mouse Problem (and What It Means for You)

Here’s a thought to sit with: mice are not small humans.

Mice live about 2 years. Humans live about 80. The biological mechanisms of aging may overlap in some ways, but the translational gap is enormous. A compound that extends a mouse’s lifespan by 10%, roughly 10 weeks, doesn’t automatically mean it extends a human’s lifespan by 10% (which would be 8 years).

Moreover, laboratory mice live in highly controlled environments, standard chow, fixed light cycles, no stress, no pollution, no alcohol, no late-night doom-scrolling. Humans live in the real world. Your habits, environment, and genetics all shape how (and whether) any supplement actually works.

The NAD+ literature is overwhelmingly rodent-based, roughly 80 mouse and rat studies versus only 33 human studies as of 2025, and many of those human studies are small pilot trials of 30 people or fewer. That’s not a solid evidence base for spending thousands of dollars or reorganizing your health routine around a molecule.

---

The Regulatory Reality Check: What Marketers Can’t Say Anymore

If you’ve been paying attention to the supplement industry lately, you’ve probably noticed that the advertising around NAD+ has gotten… aggressive.

Well, regulators have noticed too.

In November 2025, the National Advertising Division (NAD), an independent body that reviews advertising claims, recommended that a major NAD+ supplement brand discontinue multiple health claims because it lacked “competent and reliable scientific evidence.” The NAD explicitly stated there was no human clinical evidence that orally ingested NAD+, liposomal or otherwise, changes NAD+ levels in the body.

Charles Brenner, the scientist who discovered that NR is a precursor to NAD+ and is widely regarded as the leading expert in the field, has been consistently cautious. He’s warned that while NAD+ is “centrally important” to metabolism, the supplement claims piggybacking on that science are far ahead of the data.

This should matter to you, not because all supplements are scams (they aren’t), but because if a company can’t substantiate its claims when challenged, you’re making decisions based on marketing, not medicine.

---

If Not NAD+ Pills and Drips, Then What? (Lifestyle First, Supplements Second)

Here’s where I want to shift the conversation in a direction that’s actually empowering, because it would be a shame if you walked away from this article feeling like there’s nothing you can do to age well. There is. It just doesn’t come in a $500 IV bag.

The most robust, reproducible ways to support your NAD+ levels, and your overall longevity, are not glamorous, but they are free (or close to it):

• Exercise. Particularly aerobic and high-intensity interval training, which have been shown to boost NAD+ levels naturally.
• Sleep. NAD+ metabolism is tightly linked to your circadian rhythm; poor sleep disrupts it.
• Diet. Foods rich in vitamin B3, fish, nuts, whole grains, lean meats, provide the raw materials your body needs to synthesize NAD+ on its own.
• Fasting and caloric restriction. Both have been shown to activate sirtuins and increase NAD+ in animal and human studies.

If you’re doing all of these things consistently and still want to explore NAD+ precursors, NR or NMN capsules from a reputable brand with third-party testing are a far more sensible entry point than IV therapy. They’re cheaper (typically $30–$60/month vs $200–$2,000 per IV session), they’re backed by at least some human biomarker data, and they don’t require a needle.

But I want to be clear: even then, the evidence that oral NAD+ precursors will meaningfully extend your healthspan is mixed and incomplete. If a brand tells you otherwise, ask them for the human randomized controlled trial that backs it up.

---

What Should You Actually Do?

Here’s your honest decision-making framework:

If you’re excited about the science of healthy aging, and you should be, because it’s genuinely cool, the best investment you can make today is in the unsexy stuff: move your body, protect your sleep, eat real food, and be skeptical of anyone who tells you they’ve found the shortcut.

---

One more thing. The longevity field is moving fast. Subscribe to our newsletter and we’ll keep you updated when new human trials publish results, so you’ll be the first to know if the science finally catches up to the marketing.