What Is NAD+ — And Why Is Everyone Talking About It?
A cellular coenzyme, the longevity supplement of the moment, and a lot of marketing. Here's what's actually known.
- 01NAD+ is a coenzyme central to energy production and DNA repair. It declines with age.
- 02Precursors (NR, NMN, niacinamide) reliably raise blood NAD+ levels.
- 03Whether that translates to longevity benefit in humans is not yet settled.
- 04IV NAD+ is expensive, often poorly tolerated, and lacks strong outcome data compared to oral precursors.
- 05Most people who 'need NAD support' first need sleep, protein, exercise, and an alcohol reduction.
NAD+ is having a moment. It's in IV drips at wellness clinics, supplements at health food stores, and a growing pile of longevity marketing. Some of that is grounded in real biochemistry. Some of it is reaching.
This is what's actually known.
What NAD+ is
NAD+ (nicotinamide adenine dinucleotide) is a coenzyme present in every cell of your body. It's essential for:
- Energy production — converting food into ATP via the electron transport chain.
- DNA repair — as a substrate for PARP enzymes that fix damaged DNA.
- Sirtuin activity — sirtuins are enzymes involved in cellular stress response and gene regulation, and they require NAD+ to function.
- Circadian rhythm regulation at the cellular level.
It's not optional. Cells without adequate NAD+ don't function well.
Why everyone's suddenly interested
Two observations drive the attention:
- NAD+ levels decline with age. By your 60s, your tissue NAD+ may be 30–50% of what it was in your 20s.
- In multiple animal models, restoring NAD+ extends healthspan and lifespan, improves metabolic health, and protects against age-related decline.
The clinical hypothesis: maintaining NAD+ levels as you age might preserve mitochondrial function, slow some aspects of aging, and reduce age-related disease.
What raises NAD+
You can't take NAD+ orally — it doesn't survive digestion intact. So supplementation uses precursors:
- Nicotinamide riboside (NR) — well-studied precursor. Reliably raises blood NAD+ in human trials.
- Nicotinamide mononucleotide (NMN) — newer, also raises NAD+. Regulatory status in the US is currently contested.
- Niacinamide and niacin — the original B3 vitamins. Cheap. Also raise NAD+, though through somewhat different pathways. Niacin causes flushing at higher doses; niacinamide doesn't.
IV NAD+ delivers the molecule directly. It bypasses the digestion problem but introduces others: it's expensive, the infusion often causes significant chest tightness, flushing, and discomfort, and the half-life is short.
What's well-supported
- Oral NR and NMN reliably increase circulating NAD+ levels.
- In animal models, that increase translates to measurable benefits — mitochondrial function, insulin sensitivity, exercise capacity, cognitive markers.
- In human trials, NR and NMN appear safe at studied doses.
What's still hype
- That raising NAD+ in humans translates cleanly to longer life. Plausible. Not proven.
- That IV NAD+ is dramatically more effective than oral precursors. Unsupported by head-to-head outcome data.
- That a single IV infusion produces lasting cellular change. The half-life suggests it doesn't.
- That you need NAD+ supplementation for general wellness. Most people don't, at least not as a first move.
What actually raises NAD+ without a prescription
Before spending money on precursors:
- Sleep. NAD+ synthesis is circadian-coupled. Sleep is non-optional.
- Exercise. Particularly resistance training and high-intensity work raise NAD+ in muscle.
- Caloric awareness. Time-restricted eating and avoiding chronic overconsumption upregulate NAD+ synthesis.
- Alcohol reduction. Alcohol consumes NAD+ during metabolism. Heavy drinking depletes it directly.
These are the things that move the needle most. Supplements add to a foundation. They don't substitute for one.
When precursors make sense
In my practice, I sometimes recommend NR or NMN for:
- Patients in their 50s+ working on metabolic resilience.
- Patients with mitochondrial fatigue syndromes after sleep and lifestyle are dialed in.
- Patients with insulin resistance using it as one piece of a broader strategy.
I don't push it. It's optional. It's not magic.
On IV NAD+ specifically
IV NAD+ is expensive and uncomfortable. There may be a place for it in specific cases (post-illness recovery, severe deficits, some addiction medicine protocols), but for general wellness, I typically don't recommend it over oral precursors plus the foundational levers above.
If a clinic is selling weekly IV NAD+ drips as routine wellness care, ask what outcome data they're using.
Bottom line
NAD+ is real biology. The interventions are uneven. Sleep, training, alcohol moderation, and time-restricted eating raise it for free. Oral precursors are a reasonable add-on for some patients. IV is an expensive proposition without proportionate evidence.
Spend the money where the evidence is.
References
- Rajman L, Chwalek K, Sinclair DA. Therapeutic Potential of NAD-Boosting Molecules. Cell Metabolism. 2018
- Martens CR et al. Chronic nicotinamide riboside supplementation. Nature Communications. 2018
- Yoshino M et al. Nicotinamide mononucleotide increases muscle insulin sensitivity. Science. 2021
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