In this article
What NAD+ is, and why people want more of it
NAD+ (nicotinamide adenine dinucleotide) is a molecule found in every cell. It works as a helper for enzymes that regulate DNA repair, cell metabolism and immune function [6]. NAD+ levels decline with age, which is why it has become a centerpiece of "longevity" and energy clinics [2].
The idea is simple: if NAD+ falls as we age, topping it up might restore energy or slow aging. The idea comes largely from animal research. In rodents, raising NAD+ has often improved metabolism, mitochondria, inflammation and function, though results have varied between models [2]. Whether that carries over to people is the question that matters to you.
There are two ways people try to raise NAD+. One is to take a precursor, a building block the body converts into NAD+, usually as a pill. The two most studied are nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN). The other is to give NAD+ itself, by IV drip, injection or nasal spray. These are very different, and the evidence for them is very different too.
What human trials have measured
A 2026 systematic review searched for every human and rodent study of NAD+-related compounds from 2010 to October 2025 [2]. It found 33 human studies, 28 of them randomized [2]. Its summary: oral NR and NMN consistently raised NAD+-related markers in blood and were generally well tolerated over weeks to months, but effects on function, metabolism, blood vessels and other outcomes were mixed and often null [2]. The authors concluded that clinical effectiveness for anti-aging or wellness remains inconclusive [2].
| Study | Who and what | What changed | What didn't |
|---|---|---|---|
| NR in healthy older adults [3] | 30 healthy men and postmenopausal women aged 55 to 79 (24 finished); 1,000 mg NR a day by mouth vs placebo, 6 weeks each | NAD+ in blood cells rose about 60% | No obvious improvement in exercise capacity or motor function |
| NMN in postmenopausal women [4] | 25 women with prediabetes and overweight or obesity, average age about 61; 250 mg NMN a day by mouth vs placebo, 10 weeks | Muscle insulin sensitivity improved | Weight, body fat, liver fat, blood pressure, lipids, muscle strength and fatigability |
| NMN, pooled trials [7] | 15 randomized trials; 250 to 2,000 mg a day by mouth for 14 days to 24 weeks | Diastolic blood pressure dipped slightly | Body weight, BMI, blood sugar, HbA1c, lipids, systolic blood pressure |
The NMN trial deserves a closer look, because it was done in women like many of our readers: postmenopausal, with prediabetes and extra weight [4]. Ten weeks of NMN improved how well their muscles responded to insulin, measured with a detailed lab test called a clamp [4]. But it did not change their body weight, body fat, liver fat, blood pressure or blood fats, and their leg strength and how quickly their muscles tired did not change either [4]. No side effects were reported [4]. It's an interesting result in 25 women, not proof that NMN makes you feel more energetic.
Notice what none of these trials measured well: whether people felt less tired. That's the reason most women ask about NAD+, and it's the outcome with the least data behind it.
What we know about NAD+ injections and nasal sprays
Here the evidence gets much thinner. The 2026 review found no eligible outcome trials of NAD+ itself given into a vein or muscle for anti-aging or wellness [2]. The only IV NAD+ study it identified was a small pilot that tracked blood levels, not health outcomes [2].
That pilot gave 8 healthy men aged 30 to 55 an IV drip of 750 mg of NAD+ over six hours, with 3 men given saline for comparison [5]. Surprisingly, NAD+ levels in the blood didn't rise at all for the first two hours: the infused NAD+ was cleared from the blood as fast as it went in [5]. No side effects were seen at that slow rate [5].
Our NAD+ injection is given under the skin (subcutaneously) once a week, not by IV drip. We could not find any published human trial of NAD+ given under the skin for energy, fatigue or aging. That doesn't mean it can't help; it means nobody has published a test of whether it does.
The same is true of our NAD+ nasal spray. The only research on NAD+ in the nose that we found tested smell loss in mice and in lab-grown human cells [8]. We found no human trial of NAD+ nasal spray for energy or focus.
Pills (NR and NMN), IV drips, injections under the skin and nasal sprays are different routes. A result for one doesn't automatically apply to the others, so be cautious when you see oral-supplement research used to sell NAD+ shots or sprays.
Side effects people have reported
For pills, the picture is reassuring in the short term. In the NR trial, 7 of 30 participants reported 14 mild side effects, spread across both NR and placebo, and there were no serious events [3]. A 2026 pooled analysis of NMN trials found no increase in side effects, serious events, or liver enzymes compared with control groups [7].
IV NAD+ is a different story. A 2026 review of medical records from a commercial wellness clinic compared 6 clients given 500 mg of NAD+ by IV on four days in a row with 8 given NR by IV [6]. All six in the NAD+ group had moderate to severe cramping, diarrhea, nausea or vomiting, a faster heart rate, throat pain, congestion and chest pressure during the drip [6]. The symptoms stopped once the infusion ended, but they meant the drips had to be run slower, averaging 97 minutes [6]. This was a small, retrospective study, and the authors worked for the clinic, so treat it as an early signal, not a final word [6].
For our subcutaneous injection, the catalog lists redness or soreness where you inject, nausea, flushing, headache, lightheadedness and a temporary increase in heart rate. For the nasal spray, it lists nasal dryness or irritation, congestion, sneezing or brief burning, mild headache, nausea or lightheadedness, and an unpleasant taste or throat irritation. Neither is meant for you if you're pregnant or breastfeeding or have active or recent cancer, and you should tell your provider about liver, kidney or heart conditions and any medicines you take.
How to think about NAD+ if you're curious
Both of our NAD+ products are made by a licensed compounding pharmacy under your provider's prescription. Compounded drugs are not FDA-approved, which means the FDA does not verify their safety, effectiveness, or quality before they are sold [1].
- Look for the cause of your fatigue first: sleep, iron, thyroid, B12, mood, perimenopause
- Decide what you'd want to change, and track it honestly
- Stop and call your provider if you get chest pressure, a racing heart or severe nausea
- Rules out medical causes of tiredness
- Checks for reasons NAD+ isn't right for you, like pregnancy or cancer
- Reviews your medicines and conditions
- Helps you judge, after a set time, whether it's worth continuing
The honest summary: NAD+ is real biology, and precursor pills clearly raise NAD+ in the blood. But better energy, focus or slower aging haven't been shown in people, and injected or sprayed NAD+ has barely been studied at all [2]. If you'd like to try it, go in with clear expectations and a clinician on your side. You can see all of our options on the energy and recovery and sleep pages.
Frequently asked questions
What are the benefits of NAD+ injections?
No benefit has been shown in outcome trials. A 2026 systematic review found no outcome trials of NAD+ given into a vein or muscle for anti-aging or wellness [2]. We found no published trials of NAD+ injected under the skin.
Do NAD+ supplements raise NAD+ levels?
Oral precursors do. In one trial, 1,000 mg of NR a day raised NAD+ in blood cells by about 60% [3], and reviews find NR and NMN consistently raise blood markers [2]. Whether that makes you feel better is far less clear.
Is NAD+ nasal spray better than injections?
Nobody knows. We found no human trials of NAD+ nasal spray for energy or focus; the only intranasal NAD+ study we found was in mice and lab-grown cells [8].
What are the side effects of NAD+?
Oral NR and NMN were well tolerated in short trials [3, 7]. IV NAD+ caused moderate to severe stomach symptoms, a faster heart rate and chest pressure in all six people in one small clinic study [6]. Our catalog lists injection-site redness, nausea, flushing, headache and a faster heart rate for the injection.
Does NAD+ help with menopause fatigue?
It hasn't been tested for that. The one trial in postmenopausal women measured insulin sensitivity, which improved, while muscle strength, fatigability and weight did not change [4].
References
- US Food and Drug Administration. Compounding and the FDA: questions and answers. Content current as of September 16, 2025. www.fda.gov/drugs/human-drug-compounding/compounding-and-fda-questions-and-answers
- Gallagher C, Emmanuel OO. NAD+ supplementation for anti-aging and wellness: a PRISMA-guided systematic review of preclinical and clinical evidence. Ageing Res Rev. 2026;116:103057. pubmed.ncbi.nlm.nih.gov/41655607/
- Martens CR, Denman BA, Mazzo MR, et al. Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults. Nat Commun. 2018;9(1):1286. pubmed.ncbi.nlm.nih.gov/29599478/
- Yoshino M, Yoshino J, Kayser BD, et al. Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women. Science. 2021;372(6547):1224-1229. pubmed.ncbi.nlm.nih.gov/33888596/
- Grant R, Berg J, Mestayer R, et al. A pilot study investigating changes in the human plasma and urine NAD+ metabolome during a 6 hour intravenous infusion of NAD+. Front Aging Neurosci. 2019;11:257. pubmed.ncbi.nlm.nih.gov/31572171/
- Reyna K, Heinzen G, Patel N, et al. Intravenous infusion of nicotinamide adenine dinucleotide (NAD+) versus nicotinamide riboside (NR): a retrospective tolerability pilot study in a real-world setting. Front Aging. 2026;7:1652582. pubmed.ncbi.nlm.nih.gov/41704678/
- Yang W, Huang J, Tang Z, et al. Safety and metabolism-related outcomes of oral nicotinamide mononucleotide supplementation in adults: a systematic review and meta-analysis. Nutrients. 2026;18(14):2251. pubmed.ncbi.nlm.nih.gov/42514320/
- Yoo SH, Jang JY, Bae JS, et al. Therapeutic effect of intranasal nicotinamide adenine dinucleotide in the restoration of olfactory dysfunction. Exp Mol Med. 2026;58(7):2155-2167. pubmed.ncbi.nlm.nih.gov/42380286/
This article is for general information. It is not medical advice and does not replace a visit with a licensed clinician who knows your history. Do not start, stop or change a medication without talking to your clinician. If you think you are having a medical emergency, call 911.
