NAD+ is a coenzyme found in every cell, and interest in boosting it has surged. A grounded look at its biology, the human studies that exist, and the gap between laboratory findings and marketing claims.
NAD+ has gone from a biochemistry lecture topic to a wellness buzzword in a remarkably short time. It shows up in supplements, IV drips, injections and nasal sprays, often with claims about energy, aging and cellular repair. Some of those claims trace back to genuine and interesting science. Others run far ahead of it. This article explains what NAD+ actually does, what human research has and has not shown, and how to think about the products on the market, including compounded ones. It is educational and not a recommendation for any treatment.
NAD+ stands for nicotinamide adenine dinucleotide. It is a coenzyme, meaning a molecule that enzymes need in order to work, and it is present in every living cell. A 2021 review in Nature Reviews Molecular Cell Biology by Covarrubias and colleagues at the Buck Institute for Research on Aging summarizes its two broad roles.
First, NAD+ is central to energy metabolism. It shuttles electrons during the breakdown of glucose and fat, cycling between NAD+ and its reduced form NADH, and this cycling is how cells extract usable energy from food. Without it, mitochondria cannot function.
Second, NAD+ is consumed as a substrate by several families of enzymes that regulate cellular maintenance, including sirtuins (involved in gene regulation and stress responses), PARPs (involved in DNA repair) and CD38 (involved in immune signaling and calcium regulation). These enzymes use NAD+ up, which means the cell must constantly make more.
Your body synthesizes NAD+ from dietary precursors, mainly forms of vitamin B3 (niacin, nicotinamide, nicotinamide riboside) and the amino acid tryptophan. Ordinary nutrition keeps levels adequate in healthy people.
The Covarrubias review lays out the evidence that NAD+ levels decline in many tissues with age, driven by increased consumption (particularly by CD38, which rises with inflammation) and reduced synthesis. In animal studies, restoring NAD+ through precursor supplementation has improved markers of metabolic health, mitochondrial function and, in some models, lifespan or healthspan.
This is the legitimate scientific foundation for the interest in NAD+. It is also where the caution begins, because mouse results do not reliably translate to humans, and most of the dramatic findings come from animals.
Human research has focused almost entirely on oral precursors, mainly nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN), rather than NAD+ itself.
A 2023 review by Freeberg and colleagues in the Journals of Gerontology summarized the state of the evidence. Several randomized, placebo-controlled trials show that oral NR and NMN are well tolerated over weeks to months and raise NAD+ or related metabolites in blood. In a 2018 crossover trial published in Nature Communications, Martens and colleagues gave healthy middle-aged and older adults NR for six weeks and found a roughly 60 percent increase in NAD+ in blood cells compared with placebo. A 2022 Japanese trial by Okabe and colleagues found that 12 weeks of oral NMN raised whole-blood NAD+ significantly with no safety signals.
The harder question is whether raising blood NAD+ changes anything that matters. Here the Freeberg review is candid. Across trials of NMN lasting 12 weeks, some reported modest improvements in measures such as walking speed, grip strength or muscle insulin sensitivity, but many found no change in blood pressure, arterial stiffness, body composition, lipids, glucose tolerance, cognition, sleep or fatigue. The authors described the overall evidence for NMN improving physiological function as "less clear," noted that most studies enrolled healthy adults who may have little room to improve, and pointed out that measuring NAD+ accurately is technically difficult and inconsistent across labs, so even the biomarker results should be interpreted with care.
In short: oral precursors raise a blood marker; whether that produces a health benefit in humans has not been established.
Most of the products marketed as "NAD+" in clinics and online are not oral precursors. They are NAD+ itself, delivered by intravenous infusion, subcutaneous injection or nasal spray. The theory is that delivering the molecule directly bypasses the digestion and conversion steps.
The evidence for these routes is much thinner than for oral precursors. There are small studies and case series, but the peer-reviewed literature contains no large randomized controlled trials showing that injected or intranasal NAD+ improves energy, cognition, aging markers or any clinical outcome in healthy adults. Questions about how much NAD+ enters cells intact after injection, what the ideal dose would be, and whether effects differ from oral precursors remain open. Tolerability data for these routes come mainly from small studies and clinical experience rather than controlled trials.
NAD+ injections and nasal sprays are compounded medications. They are prepared by compounding pharmacies, they are not FDA-approved, and the FDA does not review compounded drugs for safety, effectiveness or quality before they are sold. The NAD+ products available through NewDay Wellness are compounded and not FDA-approved. That is not a statement that they are unsafe; it is a statement about what level of evidence and regulatory review stands behind them, which is substantially less than for an approved drug.
Because the gap between the biology and the marketing is wide, it helps to name the common claims specifically:
Being interested in a promising area of research is reasonable. Treating it as settled is not.
Published trials have mostly excluded people with significant medical conditions, pregnancy and breastfeeding, so safety in those groups is not established. Anyone with cancer or a cancer history should discuss NAD+ with their oncology team, because NAD+ metabolism is also active in tumor cells and the research in that area is unresolved. People with liver or kidney disease, and anyone taking multiple medications, should have a licensed provider review potential interactions.
NAD+ biology is real and worth following. Oral precursors appear safe in the short term and raise blood levels, with uncertain downstream benefit. Injectable and intranasal NAD+ are compounded, not FDA-approved, and supported by far less human evidence. If you choose to use any of these products, do so with clear eyes about what is and is not known, and with a licensed provider who can account for your health history.
NAD+ shuttles electrons during the breakdown of glucose and fat so cells can extract energy, and it is consumed by enzyme families such as sirtuins, PARPs and CD38 that regulate gene expression, DNA repair and immune signaling.
No human trial has shown that any NAD+ product reverses or slows aging. Oral precursors raise a blood marker, but trials have found mixed or no changes in most physiological measures.
No. NAD+ injections and nasal sprays are compounded medications prepared by compounding pharmacies, and the FDA does not review compounded drugs for safety, effectiveness or quality before they are sold.
Trials have mostly excluded people with significant medical conditions and pregnant or breastfeeding people. Anyone with cancer or a cancer history should talk with their oncology team, and people with liver or kidney disease or many medications should have a licensed provider review interactions.
If you are curious about NAD+, a licensed provider can discuss the current evidence honestly, review your medications and health history, and help you decide whether a compounded product makes sense for you. This article is educational, makes no claims about results, and does not determine eligibility for any treatment.
Written by the NewDay Wellness editorial team from the sources above and checked against them before publication, and medically reviewed by Dr. Sean Arora and Dr. Shannon Arora of Arora Health & Aesthetics; see our editorial standards. This article is educational and does not diagnose conditions, establish eligibility for any medication, or replace care from a licensed provider. Compounded medications are not FDA-approved.
NAD+ can be given by IV infusion, injection under the skin or nasal spray, but human data on these routes are small, short and mostly limited to blood levels and tolerability. No route has been shown to improve health outcomes in controlled trials.
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