Nicotinamide adenine dinucleotide — NAD+ — is a coenzyme your cells cannot run without. It carries electrons through the reactions that turn food into usable energy, and it is the substrate that sirtuins and PARP enzymes consume when they repair DNA and regulate how genes are read. When NAD+ runs low, those processes slow down.
Tissue NAD+ falls with age. That much is measurable and not seriously disputed. What follows from it is where the marketing and the research start to separate, and it is worth understanding the gap before you spend an afternoon attached to a drip.
What has actually been tested in people
Most human data concerns oral precursors rather than NAD+ itself. Nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN) both raise blood NAD+ levels reliably in humans, and both have been well tolerated in short-term studies. That part — target engagement — is established.
Whether raising the number changes how you feel or function is a separate question, and the answer so far is uneven. A 2023 trial in postmenopausal women found improved muscle insulin sensitivity with NMN. Other work has reported modest reductions in blood pressure and reduced fatigue in older adults. Against that sit trials showing no meaningful difference on the outcomes they measured.
A 2025 review in Nature Aging summarised the position bluntly: larger, longer and better-designed human trials are needed before anyone can make confident clinical recommendations. That is not a dismissal. It is the honest state of a field that is roughly fifteen years old in humans.
Where intravenous NAD+ sits specifically
Intravenous NAD+ has a narrower evidence base than the oral precursors, which surprises people who assume the more invasive route must be better studied.
The strongest published support is in opioid and alcohol withdrawal, where infusions have been used to reduce craving and withdrawal severity. For the use most patients are actually asking about — energy, mental clarity, recovery, general anti-aging in healthy adults — there is no rigorous randomised controlled trial demonstrating benefit. A 2023 systematic review looking specifically at fatigue and energy in healthy adults concluded the evidence was insufficient.
There is also an unresolved pharmacological question underneath all of this. Infusing NAD+ directly does not straightforwardly mean more NAD+ inside your cells: the molecule is large, and how much survives to cross cell membranes rather than being broken down in circulation has not been properly characterised in humans. “It goes straight into your bloodstream” is true and is not the same claim as “it goes straight into your cells.”
Why people still feel something
Patients frequently report feeling better after a course, and that report is real even where the mechanism is unproven. Several things contribute. Fatigue has many causes, and the workup that precedes a good infusion protocol — bloods, medication review, sleep and stress history — often surfaces something correctable that had been ignored for years. Iron deficiency, subclinical thyroid dysfunction and vitamin D depletion are common and all present as tiredness.
Contextual effects matter too. Lying still in a quiet room for three hours while someone attentive checks on you is not a neutral experience. None of this makes a treatment worthless, but it does explain why an honest clinic measures before and after rather than asking how you feel and calling that a result.
What a defensible protocol looks like
If you are considering NAD+ at any clinic, the process should look roughly like this.
- A consultation that investigates the fatigue rather than accepting it as the diagnosis. Persistent tiredness deserves a differential, not an infusion.
- Baseline bloods — full blood count, metabolic and liver panel, thyroid, iron studies, vitamin D, inflammatory markers — read by the physician who will supervise the treatment.
- A written note of what you want changed, in your words, before anything is infused. Sleep quality, afternoon energy, exercise recovery: whatever it is, write it down while it is still unmeasured.
- A slow infusion with the rate adjusted to you. Chest tightness, nausea and flushing are the common signs of going too fast and should prompt a slower rate, not a suggestion to push through.
- A re-test and a review at a defined point, with an agreed answer to the question of what would mean this is not working for you.
Questions worth asking before you book
Ask what dose is being used and why that dose. Ask what the clinic would expect to see change, and by when. Ask whether an oral precursor would be a reasonable first step in your case — a clinic that never recommends the cheaper option is telling you something. Ask who reviews your results, and whether that person is a physician.
Most usefully, ask what would make them advise against it. A clinician who cannot name a single reason not to treat you has not assessed you.
How ARPAR approaches it
NAD+ is one option inside a broader plan at ARPAR, not a product sold on its own. Every programme starts with diagnostics and a physician consultation, and infusion protocols are built around what the bloodwork shows rather than a fixed menu. Where the evidence is preliminary, we say so — including here.
If you want to know whether NAD+ is a sensible use of your time and money for your particular biology, that is a conversation with a doctor and a blood panel, and it is the conversation we would rather have first.