NAD+ Therapy: What It Is and What the Research Shows

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NAD+ therapy means raising the level of a coenzyme called NAD+ (nicotinamide adenine dinucleotide) with an IV drip, an injection, a nasal spray or an oral precursor such as nicotinamide riboside (NR) or nicotinamide mononucleotide (NMN). The coenzyme is real and essential, but a 2026 systematic review of 113 studies concluded that clinical effectiveness for anti-aging or wellness outcomes is still inconclusive. I’m not a medical doctor or a registered dietitian, so this guide walks through what published trials, reviews and the FDA say, what they leave unanswered, and which questions to bring to a prescriber.

This page is the overview. For the details I keep apart, see NAD+ vs NMN, NAD+ injection benefits, how much NAD+ therapy costs and NAD+ side effects.

What is NAD+ therapy and what does NAD+ do?

NAD+ is a coenzyme found in cells that helps enzymes carry out energy metabolism and other jobs. The NIH Office of Dietary Supplements explains in its niacin fact sheet for health professionals (updated November 18, 2022) that the body converts absorbed niacin into NAD, and that more than 400 enzymes need NAD to catalyze reactions. A 2021 review in Nature Reviews Molecular Cell Biology adds that NAD+ is also a cofactor for sirtuins, CD38 and PARP enzymes, and that it influences processes including DNA repair, chromatin remodelling and immune cell function.

That biology is why NAD+ draws so much interest. It is also where the marketing runs ahead of the evidence, because knowing a molecule is important does not show that adding more of it helps a healthy adult feel or function better.

Does NAD+ really fall with age?

Tissue levels fall with age in animals, and the same review says this has been reported in humans as well, but whether raising them helps people is still being worked out. The authors write that much remains to be learned about whether restoring NAD+ is safe and whether it has beneficial effects in ageing humans.

The picture in blood is less clear than the sales pages suggest. A 2026 narrative review of intravenous NAD+ in Frontiers in Aging says a large cross-sectional cohort found whole-blood NAD+ was not independently associated with chronological age once disease burden and other conditions were accounted for. So the idea that everyone’s NAD+ drops with age is less settled than it sounds.

What forms of NAD+ therapy exist?

They differ a lot in how much human research sits behind them. This table summarizes the sources on this page.

Form	What it is	What the cited human research covers	Main limit
IV NAD+ infusion	NAD+ given through a vein, usually at a clinic	Small uncontrolled studies and case reports; a 2026 review calls the evidence preliminary	No placebo-controlled outcome trials for anti-aging or wellness
NAD+ injection	NAD+ given under the skin or into muscle	The 2026 systematic review found no eligible outcomes trials of IV or intramuscular NAD+ itself for anti-aging or wellness indications	The human trials cited here did not test the injections sold online
NAD+ nasal spray	NAD+ delivered through the nose	No trial among the sources cited here	Nothing on this page supports a benefit claim
Oral NR or NMN	Precursors the body converts to NAD+	Randomized trials of 6 to 12 weeks in older adults, men with obesity and postmenopausal women	Raise blood NAD+ metabolites; clinical benefits were mixed or null

What have human trials of NAD+ boosters found?

Most controlled trials tested oral precursors, not the IV or injected products. The systematic review in Ageing Research Reviews (113 studies, 33 of them in humans, 28 randomized) found that oral NR and NMN consistently raised NAD-related metabolites and were generally well tolerated over weeks to months. Effects on functional, metabolic and vascular outcomes were heterogeneous and often null.

What did the nicotinamide riboside trials measure?

In a randomized crossover trial in Nature Communications, 30 healthy adults aged 55 to 79 were randomized to 1,000 mg of NR a day or placebo for 6 weeks each, and 24 completed the study. NR raised NAD+ metabolism and was well tolerated, with 14 mild adverse events reported by 7 of the 30 participants. The authors suggested future trials look at blood pressure and arterial stiffness. The NIH funded the work, and the supplement maker ChromaDex supplied the pills and part of the funding.

A 12-week placebo-controlled trial in the American Journal of Clinical Nutrition gave 40 sedentary men aged 40 to 70 with a BMI above 30 NR at 1,000 mg twice a day. It did not improve insulin sensitivity, resting energy expenditure or body composition, and no serious adverse events occurred. Both trials were small, and neither was built to test women over 40 specifically.

What happened in an NMN trial in postmenopausal women?

A 10-week trial in Science randomized postmenopausal women with prediabetes who had overweight or obesity to 250 mg of NMN a day or placebo. Twenty-five completed it. Muscle insulin sensitivity improved in the NMN group, but body weight and fat mass did not change in either group. The capsules came from Oriental Yeast, and some authors report patent-related interests. It is a small study whose main question was insulin action, not weight loss or how women feel.

What do the reviews conclude overall?

Two things stand out. A 2025 meta-analysis in the Journal of Cachexia, Sarcopenia and Muscle found that current evidence does not support NMN or NR for preserving muscle mass and function in adults with a mean age over 60. And a systematic review of 10 randomized trials with 489 participants in the American Journal of Physiology reported that every included study recorded some side effects, such as muscle pain, fatigue and headaches, none of them serious.

Is NAD+ therapy FDA approved?

The FDA does publish a list of substances that compounders have nominated for use. On its 503A bulk drug substances page (content current as of May 14, 2026), the FDA says category 1 substances may be eligible for the bulks list and that it does not intend to take action against a compounder using them if the guidance conditions are met. The FDA’s category list updated May 14, 2026 includes nicotinamide adenine dinucleotide (NAD) and its reduced disodium form (NADH) in category 1.

That is not an approval. In its compounding questions and answers (current as of September 16, 2025), the FDA says compounded drugs are not FDA-approved and that it does not verify their safety, effectiveness or quality before they are marketed. So when a telehealth company offers NAD+ by prescription, it is fair to ask whether the product is compounded and which pharmacy makes it.

Is NAD+ therapy safe?

Oral precursors looked well tolerated in the short trials above. The IV picture is thinner. The 2026 Frontiers narrative review says reported adverse effects include nausea, cramping, flushing and chest discomfort, and that long-term safety data are lacking. A retrospective review of commercial clients compared 500 mg of IV NAD+ (6 clients) with 500 mg of IV NR (8 clients) over four consecutive days. The NAD+ group reported moderate to severe stomach symptoms, a faster heart rate and chest pressure during infusions, and their infusions took 97 minutes on average versus 37 minutes for NR. Symptoms stopped when the infusion ended. The study had no placebo group and was funded by Restore Hyper Wellness, whose employees wrote it.

There are also theoretical concerns. A 2020 systematic review listed possible risks of raising NAD+ as accumulation of putative toxic metabolites, tumorigenesis and promotion of cellular senescence, while noting long-term human trials are still nascent. My NAD+ side effects guide goes through what has been reported.

Can NAD+ therapy help with weight loss?

The trials above do not show it. The men with obesity in the NR trial had no change in body composition, and the postmenopausal women in the NMN trial had no change in body weight or fat mass. If weight is your goal, I wrote up the evidence in NAD+ for weight loss in women, and the prescription weight loss medicines I cover are in my GLP-1 weight loss guide.

How do you get NAD+ therapy?

On its NAD+ page, read on October 26, 2026, Shed says it offers NAD+ nasal spray and NAD+ injections. It describes the steps as an online medical questionnaire, a plan selection and checkout, and a licensed provider who reviews your information and ships medication if you are approved. Those are the company’s own statements. The same page lists slowed aging and reduced cognitive decline among the areas NAD+ supports, and none of the trials cited here tested or showed either.

What should you ask a prescriber or pharmacy?

Is this product compounded, and which licensed pharmacy makes it?
What published human trial tested this exact form (IV, injection or spray) and for what outcome?
What side effects should I watch for, and who do I call if they happen?
Does anything in my history, my medicines or my GLP-1 treatment change the answer?

Please talk to your doctor or pharmacist before starting anything on this page, especially if you take a GLP-1 or other prescription medicine, have thyroid, kidney or liver disease, or are pregnant or nursing. This page is research, not medical advice.

Frequently Asked Questions

What is NAD+ therapy used for?

Shed’s NAD+ page markets it for energy production, metabolism, slowed aging and healthy brain function. The 2026 systematic review found the clinical effectiveness of NAD+ augmentation for anti-aging or wellness outcomes inconclusive, so a use is not established by those sources.

Is NAD+ the same as NMN or NR?

No. NAD+ is the coenzyme itself. NR and NMN are precursors that the body converts toward NAD+. The NIH Office of Dietary Supplements describes nicotinamide riboside and NMN as niacin-like compounds that are not marketed or labeled as sources of niacin.

Does NAD+ therapy work?

In trials, oral precursors raised blood NAD+ metabolites, but clinical results were mixed or null. For IV NAD+ a 2026 narrative review in Frontiers in Aging calls the evidence preliminary and insufficient to support routine clinical or wellness use.

How long does NAD+ therapy take to work?

No source on this page reports a timeline for a feel-better effect. The trials measured NAD+ metabolites and lab outcomes over 6 to 12 weeks, and the main NR trial found no change in body composition at 12 weeks.

Is NAD+ therapy safe to use with a GLP-1 medicine?

The studies cited here did not test NAD+ together with a GLP-1, so I cannot say. Bring both to your prescriber, who knows your history and can check for problems.

Why do the IV, injection and pill forms get mixed together?

The 2026 systematic review found no eligible outcomes trials of IV or intramuscular NAD+ itself for anti-aging or wellness indications, so results from pills do not transfer automatically.

Sources

NAD+ Therapy: What It Is, What Research Shows and What Is Unproven