NAD+ Injection: What It Is, Where to Get It Prescribed, and What It Costs

NAD+ is nicotinamide adenine dinucleotide. It is not a peptide. It is a coenzyme — two nucleotides joined through a pyrophosphate bridge, one carrying nicotinamide (a form of vitamin B3), the other adenine. Every living cell makes it and uses it continuously.

The body builds it from tryptophan, from niacin, and — the main route in adult tissue — by recycling nicotinamide via nicotinamide mononucleotide (NMN). Nicotinamide riboside (NR) is another entry into that salvage pathway. NMN and NR are the "precursors" sold as supplements, and most of the human trial literature is about them, not about NAD+ itself. Keeping that distinction straight is the most useful thing a reader can do with this topic.

The plus sign marks the oxidised form: NAD+ accepts electrons and becomes NADH, NADH gives them up and becomes NAD+ again, thousands of times a second in every mitochondrion. The injection contains the oxidised form, which is what the sirtuin and PARP enzymes below consume.

It is not a vitamin, although it is made from one. It is not a hormone or growth factor, and it does not bind a receptor the way a peptide does. It is not a stimulant. It is not the same thing as NMN or NR, so precursor results cannot simply be transferred to it. And it is not a treatment for any diagnosed disease, because it has no approved indication.

NAD+ collects electrons from the breakdown of glucose and fatty acids and delivers them, as NADH, to the mitochondrial electron transport chain to make ATP. This is textbook metabolism, and why NAD+ deficiency at the extreme — pellagra — is a recognised disease.

Sirtuins are seven enzymes (SIRT1 to SIRT7) that remove acetyl groups from proteins and consume NAD+ each time they act. In animals their activity is described as tracking NAD+ availability, and a 2015 review in Science by Verdin set out the case that declining NAD+ limits sirtuin function with age. More NAD+ is therefore proposed to allow more sirtuin activity — a mechanism argument, not a human outcome.

PARP enzymes respond to DNA damage by building chains of ADP-ribose at the break site, each unit costing one NAD+. A 2014 review in Cell Cycle by Fang and Bohr described how PARPs and sirtuins drawing on the same limited pool links DNA repair to mitochondrial maintenance in cells and in animal models of accelerated ageing.

CD38, an enzyme on immune and other cells, breaks NAD+ down and is reported to rise with age and chronic inflammation in animal tissue; add PARP demand from accumulating DNA damage and the pool shrinks. A 2012 study in PLOS ONE by Massudi and colleagues measured this in human skin across age groups and reported lower NAD+ and higher oxidative-stress markers in older tissue. That is human data, and it is observational: it shows the decline, not that reversing it changes anything.

NAD+ is a large, charged molecule and does not simply diffuse into cells. The only published study of NAD+ given directly to people — a 2019 pilot in Frontiers in Aging Neuroscience by Grant and colleagues, a six-hour intravenous infusion in healthy participants — found that plasma NAD+ and its metabolites did not rise at all for the first two hours: the infused molecule was cleared as fast as it arrived, with a metabolite profile consistent with the enzymes that break NAD+ down. The likeliest reading is that injected NAD+ is broken down outside cells into fragments, including nicotinamide and NMN, which tissues rebuild into NAD+ through the same salvage pathway a precursor uses. That is a hypothesis from one small infusion study; nothing equivalent has been published for the subcutaneous route.

The human trials are mixed. A 2018 trial in the American Journal of Clinical Nutrition by Dollerup and colleagues gave 40 obese, insulin-resistant men NR or placebo for 12 weeks and reported no improvement in insulin sensitivity, glucose metabolism, energy expenditure or body composition. A 2021 trial in Science by Yoshino and colleagues gave postmenopausal women with prediabetes NMN or placebo for 10 weeks and reported increased skeletal-muscle insulin sensitivity on clamp testing — positive, in a small selected group. A 2023 GeroScience trial in 80 middle-aged adults reported dose-dependent rises in blood NAD+ over 60 days and longer six-minute walk distances than placebo. Summed up: precursors reliably raise blood NAD+; functional effects are small, inconsistent, and strongest in older or metabolically impaired participants.

The NADPARK study, Cell Metabolism 2022, gave 30 newly diagnosed, untreated Parkinson's patients NR or placebo for 30 days and reported that brain NAD levels, measured by phosphorus MR spectroscopy, rose in the treated group, with altered cerebral metabolism on PET and lower inflammatory cytokines. The clinical change was described as mild, the trial was phase I, and larger trials are ongoing.

The first controlled trial of NR in healthy middle-aged and older adults — Martens and colleagues, Nature Communications 2018 — reported it was well tolerated, raised NAD+ in blood cells, and produced a blood-pressure signal the authors flagged for future trials rather than claimed. The 2024 NICE trial in Nature Communications randomised 90 people with peripheral artery disease to six months of NR or placebo and reported a 17.6-metre between-group improvement in six-minute walk distance, with a confirmatory trial called for.

For NAD+ given directly, the honest summary is short. There is the 2019 intravenous pilot, which measured what happens to the molecule in blood and urine and tested no clinical outcome. There are no randomised controlled trials of subcutaneous NAD+ injection in humans, and no randomised trial of NAD+ by any injected route with a clinical endpoint.

• It does not establish that subcutaneous NAD+ injection raises tissue NAD+ in humans, by how much, or for how long.
• It does not establish an effect on fatigue, cognition, longevity or any ageing marker from injected NAD+. Where those endpoints were tested, the molecule was an oral precursor and the results were small and mixed.
• It does not establish efficacy for any condition as an approved treatment. NAD+ is not approved for anything.

Nicotinamide adenine dinucleotide (NAD) sits in Category 1 — "Bulk Drug Substances Under Evaluation" — of the FDA's list of substances nominated for the 503A bulks list, in the version updated 14 May 2026. Under the FDA's interim policy, the agency does not intend to take action against a compounder using a Category 1 substance while its evaluation is pending, provided the conditions in the guidance are met. That is the basis on which a state-licensed 503A pharmacy compounds NAD+ to a prescription today.

The nomination under evaluation was for a 5 mg oral capsule for fatigue in multiple sclerosis. At the Pharmacy Compounding Advisory Committee meeting on 8 May 2017 the FDA's reviewers recommended against listing, citing the molecule's instability — it degrades on heating, in alkaline solution and in light — and thin evidence for the nominated use, and the committee voted 1 yes to 7 no. The FDA carried that position into a September 2019 proposed rule that would not include NAD on the list. That rule has not been finalised for NAD as of September 2026, which is why the substance remains in Category 1 and compoundable under the interim policy.

On 15 April 2026 the FDA removed twelve peptides from Category 2, and on 23–24 July 2026 the advisory committee reviewed seven of them. NAD+ was not among the twelve, because it was never in Category 2, and it was not on the July agenda. Separately, on 30 October 2024 the FDA reminded compounders that food-grade NAD+ powder is not suitable for sterile injectable compounding without appropriate processing, after adverse-event reports consistent with endotoxin contamination. That is about ingredient sourcing at the pharmacy, not NAD+ as a molecule; Pepti's sourcing and testing is on the quality page.

So the accurate description today is: nominated, under FDA evaluation, compoundable under the interim policy. It is not an FDA-approved drug product, and compounded medications never are.

The most consistently reported early experience is not a benefit but a sensation: flushing, tightness in the chest or abdomen, or nausea during the injection, fading within minutes. Some people notice nothing at all in the first week. Neither says anything about the course.

If anything is reported subjectively, prescribers describe it in this window — usually a change in how tiring ordinary days feel, or in sleep. That is consistent with the precursor trials, where blood NAD+ was raised by day 30 — and with placebo.

NAD+ has no receptor to downregulate and no feedback loop to suppress, so nothing in the literature describes withdrawal or rebound. The body keeps making its own NAD+ at whatever rate it did before.

The directions are written in millilitres and in insulin-syringe units because that is what you can read off the barrel. 0.83 mL is 83 units on a U-100 syringe. You are not calculating anything — the number is printed on your medication.

Subcutaneous means into the fat layer, not the muscle. Abdomen and thigh are the usual sites, rotated. With NAD+ specifically, prescribers consistently advise injecting slowly: the flushing and nausea described under safety track with how fast the molecule enters the circulation — and a slow injection is the simplest way to blunt it. Your directions will say.

12 doses at three times per week is four weeks, which is why refills run on a 28-day cycle. One vial per fill, always — not a stockpile.

Refrigerated, and it ships that way in insulated packaging with ice packs. Storage matters more than usual here: the FDA's own 2017 review describes the molecule as reactive, degrading with heat, alkaline pH and light. Keep it in the fridge, out of light, and follow the beyond-use date on the label, which runs from first puncture.

The precursors have the trial evidence; the injection has the direct route. Injected NAD+ bypasses the gut and, on the 2019 infusion data, appears to be broken down in the blood into fragments that cells rebuild through the salvage pathway. Whether that makes the injection more effective, equivalent, or simply more expensive has not been tested head to head.

This injection product is supplied as a vial or Pen only. Pepti separately supplies an NAD+ Nasal Spray, a different product with its own directions. The nasal route avoids needles and the injection-speed reaction, at the cost of a less predictable absorbed dose; there is no published human pharmacokinetic comparison between the two.

The three products on this site described around mitochondrial function are not interchangeable. NAD+ is a substrate the machinery consumes. MOTS-c is a peptide encoded in mitochondrial DNA, described in animal work as a metabolic signal acting through AMPK. SS-31 is a peptide described as binding cardiolipin in the inner mitochondrial membrane, and it has been through randomised human trials for a rare mitochondrial disease.

Identical medication. The pepti Pen is a pre-filled cartridge in a reusable click-dial injector, dosed in clicks rather than drawn from a vial with a syringe. It costs more and it removes the draw step. Neither is clinically better.