NAD+ (nicotinamide adenine dinucleotide) is one of the most talked-about molecules in wellness, and one of the most oversold. At Calibrate IV, our approach is evidence first: here is what the research shows, where it runs out, and how our physician-guided NAD+ options fit into that picture.

What NAD+ does in your body

NAD+ is a coenzyme found in every cell. It helps shuttle electrons during energy production in the mitochondria, and it is used by enzyme families involved in cellular maintenance, including sirtuins and PARPs. Those roles are well-established biochemistry.

The popular claim that NAD+ declines with age and that restoring it can slow aging is less settled in humans. A 2019 human study in Cell Reports noted that the age-related decline has mostly been described in preclinical models, and that human data are sparse (Elhassan et al., 2019). Much of the excitement around sirtuins and “longevity pathways” also comes from animal and laboratory work.

What human studies have actually shown

Most human research has tested oral NAD+ precursors, especially nicotinamide riboside (NR), rather than NAD+ given by injection or IV. Here is a snapshot, labeled by study type:

• Raising NAD+ levels (human randomized crossover trial, Martens et al., Nature Communications, 2018): In 24 healthy adults aged 55 to 79, six weeks of 1,000 mg/day of oral NR was well tolerated and raised blood NAD+ by roughly 60%. Blood pressure changes in a small subgroup were exploratory, and the authors described the study as a pilot.
• Muscle and inflammation markers (human randomized crossover trial, Elhassan et al., Cell Reports, 2019): In 12 older men, 21 days of 1 g/day oral NR increased the NAD+ metabolome in skeletal muscle and lowered circulating inflammatory cytokines, without changing muscle mitochondrial bioenergetics.
• Metabolic outcomes (human randomized placebo-controlled trial, Dollerup et al., American Journal of Clinical Nutrition, 2018): In 40 obese, insulin-resistant men, 12 weeks of 2,000 mg/day oral NR appeared safe but did not improve insulin sensitivity or whole-body glucose metabolism. A follow-up analysis found no change in skeletal muscle mitochondria (Journal of Physiology, 2020).

The takeaway: precursors reliably raise NAD+-related markers, but whether that translates into noticeable benefits is still being worked out, and results so far are mixed.

The honest gap: injectable and IV NAD+

Here is where we think you deserve plain talk. A 2026 systematic review in Ageing Research Reviews (Gallagher and Emmanuel) covered 113 intervention studies, 33 in humans and 80 in rodents, and found no eligible controlled outcome trials of intravenous, intramuscular, or subcutaneous NAD+ for anti-aging or general wellness goals. A 2026 narrative review in Frontiers in Aging (Alkhodairy) reached a similar conclusion: available human IV data are sparse, come mostly from small uncontrolled studies, and do not support firm conclusions about long-term safety.

What does exist is early pharmacokinetic work, such as a 2019 human pilot study that tracked NAD+ and its metabolites in blood and urine during a six-hour IV infusion. That tells us what happens to infused NAD+ in the body. It does not tell us whether it improves how people feel or function.

In short, NAD+ is a legitimate area of active science, and direct IV or injectable NAD+ is still an under-studied one. We would rather say so than promise results.

Three ways to explore NAD+ with Calibrate IV

Every Calibrate IV option is physician-guided, and the decision of which one suits you starts with a conversation with our clinical team.

NAD+ Injectable HomeKit

Four prefilled syringes of 250 mg NAD+ each (1,000 mg in total), designed for self-administration at home. It suits people who prefer a flexible routine and are comfortable administering injections after guidance from our team. Add-on options such as B12, magnesium, thiamine, B complex, and zinc can be discussed with your nurse.

NAD+ Executive

An NAD+ session delivered by a licensed RN, either at one of our locations in Miami, New York, or Las Vegas or through our mobile service. Skip the waiting room and have your session where it fits your day. Your nurse can walk you through add-on options.

Niagen (nicotinamide riboside)

Niagen is the patented form of nicotinamide riboside, the NAD+ precursor behind much of the human research summarized above. It is a different approach from NAD+ itself: rather than supplying NAD+ directly, a precursor gives your cells a building block to make it. Most of the published human trials used oral NR, so ask our clinicians how that evidence relates to the option you are considering.

Who should talk to a clinician first

Please review any NAD+ or NAD+ precursor product with a licensed clinician before starting, especially if you are pregnant or nursing, take prescription medications, or have a chronic medical condition. Because cancer cells also depend on NAD+ metabolism in laboratory research, anyone with a current or past cancer diagnosis should check with their oncology team first. Our team will review your history so the plan fits you.

Questions to ask before you choose

• What outcome am I hoping to support, and what does the evidence say about it?
• Is the evidence for this specific route (oral, injectable, or IV) or for a related precursor?
• Does anything in my medications or medical history change the plan?
• How will we decide together whether it is working for me?

Frequently asked questions

Is NAD+ the same as NR?

No. NAD+ is the coenzyme itself. Nicotinamide riboside (NR) is a form of vitamin B3 that the body can convert into NAD+.

Does IV or injectable NAD+ treat any condition?

No. NAD+ offerings at Calibrate IV are intended to support general wellness and are not intended to diagnose, treat, cure, or prevent any disease.

Is the research on NAD+ conclusive?

Not yet. Oral precursor trials show NAD+ levels can rise. Evidence on outcomes, and especially on injectable and IV NAD+, is still developing.

Ready to talk it through?

Our physician-guided team will help you decide whether NAD+ makes sense for you, and which format fits. Call 1-844-416-2546 or email concierge@calibrateiv.com. Visit calibrateiv.com or follow us at @calibrateivhydration.

References

1. Martens CR, et al. Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults. Nat Commun. 2018;9:1286. (Human randomized crossover trial)
2. Elhassan YS, et al. Nicotinamide riboside augments the aged human skeletal muscle NAD+ metabolome and induces transcriptomic and anti-inflammatory signatures. Cell Rep. 2019;28(7):1717-1728. (Human randomized crossover trial)
3. Dollerup OL, et al. A randomized placebo-controlled clinical trial of nicotinamide riboside in obese men: safety, insulin-sensitivity, and lipid-mobilizing effects. Am J Clin Nutr. 2018;108(2):343-353. (Human randomized controlled trial)
4. Dollerup OL, et al. Nicotinamide riboside does not alter mitochondrial respiration, content or morphology in skeletal muscle from obese and insulin-resistant men. J Physiol. 2020;598(4):731-754. (Human randomized controlled trial)
5. Grant R, et al. A pilot study investigating changes in the human plasma and urine NAD+ metabolome during a 6 hour intravenous infusion of NAD+. 2019. (Human pilot, pharmacokinetic)
6. Gallagher C, Emmanuel OO. Systematic review of NAD+-related interventions (33 human and 80 rodent studies). Ageing Res Rev. 2026. (Systematic review)
7. Alkhodairy F. Narrative review of intravenous NAD+ and NAD+ precursors in wellness and translational medicine. Front Aging. 2026;doi:10.3389/fragi.2026.1887175. (Narrative review)

This article is for educational purposes only and is not medical advice. Statements have not been evaluated by the FDA. Calibrate IV products and services are not intended to diagnose, treat, cure, or prevent any disease. Consult a licensed clinician before starting any new wellness protocol.