The NAD+ Hype Is Running Ahead of the Science
It's a question we hear more every month: a patient asks about the NAD+ IV drip they saw at a wellness lounge, or a bottle of NMN capsules a friend swears is keeping them young. The marketing is confident. The actual research is a lot more careful than the marketing lets on.
The short version
What NAD+ actually is
NAD+ (nicotinamide adenine dinucleotide) is a coenzyme every cell needs to turn food into usable energy and repair DNA. Levels naturally decline with age, which is exactly the hook wellness marketing has run with: IV drip lounges now advertise NAD+ infusions alongside vitamin drips, and NMN and NR (nicotinamide mononucleotide and nicotinamide riboside, the two supplement forms your body converts into NAD+) have become fixtures of the longevity-supplement aisle.
NMN's regulatory rollercoaster
This is worth knowing if you've seen conflicting headlines. The FDA excluded NMN from the legal definition of a dietary supplement in November 2022, after a drugmaker had already started studying it as a prescription drug candidate. An industry group sued, and in September 2025 the FDA reversed course, confirming NMN is lawful to sell as a supplement again. If you'd heard NMN was “banned” at some point, that's why — and it no longer is.
The consistent finding
Across studies, NAD+ precursors reliably do what they're supposed to do at the cellular level — they raise NAD+ concentrations in blood, and in some trials, in muscle and cerebrospinal fluid too. That part isn't in dispute.
Where it gets more specific
A 2024 randomized trial in Nature Communications found NR improved six-minute walking distance by 17.6 meters over six months in people with peripheral artery disease, compared to placebo. A 2023 NMN trial in postmenopausal women showed improved muscle insulin sensitivity. Small trials in Parkinson's disease found NR safe and able to raise NAD+ metabolites in spinal fluid, though whether that slows the disease itself is still being studied.
Where it falls short
A 2025 randomized trial in long-COVID patients found NR raised NAD+ levels within five weeks, but didn't produce a significant improvement in cognition, fatigue, sleep, or mood compared to placebo — a clean example of the marker moving without the symptom moving with it. Most trials in generally healthy or overweight adults haven't shown meaningful changes in body composition or metabolic health either.
Safety
Short-term studies at typical doses (300mg to 2000mg daily for NR) haven't turned up serious safety signals, and researchers describe tolerability as generally favorable. That said, most of the safety data is short-term, and it applies to studied oral supplement doses — not necessarily to the IV NAD+ infusions sold at wellness lounges, which have far less rigorous trial data behind them than the oral capsules do.
Bottom line
NAD+ precursors are biologically active and appear safe short-term, and a few specific conditions (peripheral artery disease, and possibly Parkinson's) have real, if early, evidence behind them. “Anti-aging” and general energy claims for healthy adults are still ahead of what the research has actually proven. If you're curious whether it's worth trying for what you're actually dealing with, that's a conversation for a provider who can weigh it against your history — not a wellness-lounge menu.
Sources: PubMed / ScienceDirect PRISMA-guided systematic review (2026); Nature Communications (NICE peripheral artery disease trial, 2024); eClinicalMedicine (long-COVID randomized trial, 2025); npj Aging (systems-based NAD+ supplement trial); U.S. FDA regulatory determinations (2022, 2025).