NAD+ stands for nicotinamide adenine dinucleotide. It’s a mouthful, but the concept is simple: NAD+ is a coenzyme—a helper molecule—found in every single cell of your body .
Think of NAD+ as the “shuttle bus” of your cellular power plants (mitochondria). It picks up electrons from the food you eat and drops them off to create ATP, the energy currency that powers everything from your heartbeat to your workouts .
But energy production isn’t NAD+’s only job. It also serves as fuel for three critically important enzyme families :
- Sirtuins (SIRTs): Often called “longevity genes,” these proteins regulate aging, inflammation, and stress resistance. They can’t function without NAD+.
- PARPs: These enzymes repair damaged DNA—something that happens thousands of times per day in every cell.
- CD38: This enzyme consumes NAD+ and becomes more active with age.
Here’s the problem: NAD+ levels naturally decline as you get older. By middle age, your levels may be half of what they were in your youth . This decline is linked to many hallmarks of aging, including metabolic dysfunction, cognitive decline, and reduced physical performance.
How Do You Increase NAD+?
There are three main ways to boost NAD+ levels, ranging from lifestyle to supplementation to clinical treatments.
1. Exercise (Free and Proven)
You don’t need a supplement to boost NAD+. Regular exercise—both endurance and resistance training—naturally increases NAD+ levels in skeletal muscle . In fact, research suggests that exercise and NAD+ supplementation may work synergistically, meaning combining both could give you better results than either alone .
2. Dietary Precursors (The Supplements)
NAD+ itself is poorly absorbed when taken orally. Instead, supplements use precursors—smaller molecules that your body converts into NAD+. The two most common are:
| Precursor | Full Name | Status |
|---|---|---|
| NR | Nicotinamide Riboside | Widely available, generally recognized as safe |
| NMN | Nicotinamide Mononucleotide | Regulatory status has fluctuated; currently legal as a dietary ingredient as of late 2025 |
These precursors are forms of vitamin B3 and are found naturally in small amounts in foods like milk, yeast, and vegetables .
3. IV and Injection Therapy
Some clinics offer NAD+ as an intravenous (IV) infusion or intramuscular (IM) injection. These bypass the digestive system and deliver NAD+ directly into the bloodstream. Dosing in case studies has ranged from 500 mg to 1,500 mg per infusion .
A clinical trial is currently underway to evaluate the safety of injectable NR (Niagen® Plus) at doses of 50 mg and 100 mg .
Important caveat: NAD+ IV therapy is not FDA-approved for any medical condition, and long-term safety data is limited .
What Does the Science Say? Potential Benefits (With Caveats)
The research on NAD+ is exciting, but most high-quality evidence comes from animal studies. Human data is still emerging, and many studies are small or short-term .
Here’s what we know so far.
May Reduce Inflammation
This is the most consistent finding in human studies. Supplementing with NR has been shown to reduce inflammatory markers, particularly interleukin-13 (IL-13) . However, whether this reduction translates to lower risk of chronic disease hasn’t been proven yet.
Possible Cognitive Benefits for Certain Populations
A small study of 15 people with early Parkinson’s disease found that 1,000 mg of NR per day for 30 days increased NAD+ levels in the brain and reduced inflammatory cytokines . Researchers believe NR may help slow disease progression, but larger studies are needed.
For healthy individuals, NAD+ has not been shown to boost cognitive function .
May Improve Metabolic Health
NAD+ may enhance insulin sensitivity, which could lower the risk of type 2 diabetes. One study found that overweight women with prediabetes who took NMN for 10 weeks showed improved insulin sensitivity .
Heart Health Potential
A meta-analysis of 29 studies found that NAD+ precursor supplementation led to significant reductions in blood pressure and inflammation—two major risk factors for cardiovascular disease . However, this analysis included studies using niacin, which has side effects that limit its use.
Physical Performance
Research suggests that maintaining NAD+ homeostasis is important for exercise adaptation and athletic capacity. One review concluded that “restoring impaired NAD+ homeostasis can improve exercise performance” . This is particularly relevant for older adults or those with age-related decline.
What Are the Risks and Side Effects?
Generally, NAD+ precursors like NR and NMN are considered safe and well-tolerated in short-term use .
Common Side Effects
At higher doses, some people experience:
- Nausea or indigestion
- Headache
- Fatigue
- Skin flushing (especially with niacin-based precursors)
A 2024 systematic review of 10 studies (489 participants) found that side effects were generally mild and did not present serious risks to health .
Important Warnings
- Cancer concern: Because NAD+ boosts cellular activity, there is a theoretical concern that it could encourage abnormal cells, like cancer cells, to survive. Longevity doctors often advise avoiding NAD+ supplementation in patients with active cancer as a precaution .
- Pregnancy/Breastfeeding: Avoid due to lack of safety data .
- Long-term safety unknown: Most studies are short-term. The long-term effects of chronic NAD+ elevation have not been established .
NAD+ vs. Precursors: What Should You Take?
If you’re considering an NAD+ supplement, here’s a quick guide:
| Form | Bioavailability | Best For | Notes |
|---|---|---|---|
| NR (Nicotinamide Riboside) | Good | General NAD+ boosting | Well-studied, generally safe |
| NMN (Nicotinamide Mononucleotide) | Good | General NAD+ boosting | Regulatory status evolving; legal as of late 2025 |
| NAD+ itself (oral) | Poor | Not recommended | Body doesn’t absorb it well |
| NAD+ IV/Injection | High | Clinical settings | Not FDA-approved; expensive; limited safety data |
Bottom line: If you want to try an oral supplement, stick with NR or NMN from a reputable brand with third-party testing (USP, NSF, or ConsumerLab) .
Dosage: What’s the Right Amount?
There is no standard dose yet. Research has typically used:
- NR: Up to 1,000 mg per day
- NMN: Around 250 mg per day
The tolerable upper limit for NR is approximately 3 mg per kilogram of body weight per day (about 180 mg for a 132-pound adult) . However, many studies exceed this without serious adverse effects.
As always, talk to your healthcare provider before starting any new supplement regimen.
The Bottom Line
NAD+ is a fascinating molecule with real biological importance. The science is promising, especially in the areas of inflammation, metabolic health, and age-related decline. But the hype has outpaced the evidence.
Here’s what you need to remember:
- NAD+ declines with age, and that decline is linked to many aspects of aging.
- Exercise is a proven, free way to boost NAD+ naturally.
- Precursor supplements (NR, NMN) are generally safe and may offer benefits, but long-term data is lacking.
- IV NAD+ therapy is experimental, not FDA-approved, and carries unknown risks.
- Avoid NAD+ if you have active cancer or are pregnant/breastfeeding.
The “miracle molecule” narrative is tempting. But the most responsible approach is to focus on lifestyle first (exercise, sleep, nutrition), talk to your doctor, and view NAD+ supplementation as an emerging area of research—not a proven fountain of youth.
Disclaimer: This article is for informational and educational purposes only and does not constitute medical advice. The U.S. Food and Drug Administration (FDA) does not approve dietary supplements for safety or effectiveness. Always consult a licensed healthcare provider before starting any new supplement, especially if you have a medical condition or are taking medications.
