NAD+

What it is

NAD+ (nicotinamide adenine dinucleotide) is a coenzyme, not a peptide. It is a cofactor for enzymes that regulate DNA repair, cellular metabolism and immune function [2]. When DNA is damaged, the repair enzyme PARP1 consumes NAD+ to build polymers of ADP-ribose [1]. NAD+ itself cannot be absorbed intact from the gut or taken up directly by cells, which is why oral products use precursors such as nicotinamide riboside (NR), NMN or niacin instead [2]. Commercial clinics increasingly offer intravenous NAD+ despite limited evaluation of its safety and effectiveness [2]. When a prescriber includes NAD+ in a plan, it is a compounded injectable, and compounded drugs are not FDA-approved [7]. STACK lists it as a tracked compound with no reference half-life.

How it works

Once in the blood, NAD+ is broken down by several enzyme families: sirtuins, ADP-ribose transferases, PARPs, and the glycohydrolases CD38 and CD157, which sit on the surface of many cell types, including red blood cells [1]. In the only published human infusion study, plasma NAD+ did not rise at all during the first 2 h of a 6 h infusion, which the authors read as rapid and complete tissue uptake and/or metabolism [1]. By 6 h, NAD+ and its metabolites nicotinamide, methylnicotinamide and ADP-ribose had each climbed roughly 400% above baseline, a pattern consistent with NAD+ glycohydrolase activity [1]. Urine contained NAD+ itself and methylnicotinamide, but not nicotinamide [1]. A 2026 review of clinic records suggests the infusion symptoms people report may relate to a pro-inflammatory effect of supraphysiologic extracellular NAD+ [2].

What the evidence shows

Human data are thin. Grant et al. (2019) enrolled eleven men aged 30–55: eight received 750 mg NAD+ in saline over 6 h (about 2 mg/min) and three received saline, with blood and urine sampled to 8 h [1]. The study described the changes in plasma and urine metabolites; it was not designed to test any clinical benefit [1]. A 2026 retrospective review compared six clinic clients who received 500 mg NAD+ intravenously on four consecutive days with eight who received NR; liver enzymes, hsCRP, kidney markers and TSH did not change, exploratory metabolic outcomes were variable, and the authors called for further studies [2]. In its 2019 evaluation, FDA found no published studies supporting the use it reviewed (fatigue in multiple sclerosis) and insufficient clinical data to judge safety in compounded drugs [5].

Regulatory status

NAD+ is not an FDA-approved drug [7]. On FDA’s list of substances nominated for 503A compounding, updated May 14 2026, “Nicotinamide Adenine Dinucleotide (NAD)” appears in Category 1, the group still under evaluation [3]. For Category 1 substances FDA says it does not intend to take action against a compounder, provided the conditions in its interim guidance are met, until it decides on the bulks list [4]. That decision is pending: in a proposed rule published Sep 5 2019, FDA proposed that NAD not be placed on the 503A bulks list, noting that the advisory committee had voted against it on May 8 2017 [5]. Separately, NAD+ is not on the 503B bulks list; a Jan 20 2026 warning letter cited an outsourcing facility for compounding NAD+ products that were not eligible for 503B exemptions [6].

Half-life and what it means for a level curve

No human elimination half-life for NAD+ has been published. The one infusion study saw no rise in plasma NAD+ or its metabolites until after 2 h, a peak at the end of the 6 h infusion, and nicotinamide back to control levels 2 h later; it did not calculate a half-life [1]. The infusion route and the immediate tissue uptake mean a subcutaneous or intramuscular half-life cannot be inferred from it either. STACK has no reference half-life for this compound because no human value has been published; you can enter your own estimate. If you do, remember that a level reaches about 97% of steady state after roughly five half-lives of regular dosing, and that the shape depends entirely on the number you typed. STACK’s curve is an estimate from this published half-life, not a blood level.

Reported side effects

In the Grant study, no adverse events were observed in the eight men infused at about 2 mg/min, and small changes in liver enzymes and bilirubin were not considered clinically significant [1]. In the 2026 clinic review, all six people receiving NAD+ reported moderate to severe abdominal cramping, diarrhea, nausea, vomiting, increased heart rate, throat pain, congestion and chest pressure during the infusion; symptoms stopped as soon as the infusion ended, and infusions averaged 97 min versus 37 min for NR [2]. Product quality is a separate risk: FDA’s Jan 20 2026 warning letter describes three patients who developed low blood pressure, uncontrollable shaking, shivers and body aches after a compounded NAD+ product and were sent to the emergency room; an unopened vial from the same lot contained 3,360 EU/mL of bacterial endotoxin [6]. Call your prescriber about any reaction during or after a dose.

Storage and handling

In its 2019 evaluation FDA wrote that NAD degrades substantially when exposed to light, moisture, alkaline pH or standard room temperatures, and would not be stable under ordinary storage conditions without compensatory measures [5]. That is why the pharmacy’s label governs: follow its refrigeration instructions, keep the vial protected from light, and respect the beyond-use date printed on it. FDA does not verify the safety, effectiveness or quality of compounded drugs before they are marketed, so the compounder’s labeling is the only product-specific guidance you have [7]. If your product arrives as a powder, STACK’s reconstitution calculator does the concentration math for you; it does not suggest what to take.

What STACK tracks for it

STACK logs each NAD+ dose exactly as your prescriber wrote it, with the route (IV, subcutaneous or intramuscular), the date and time, and how long an infusion took. Because there is no published human half-life, the estimated-level curve stays off unless you enter your own estimate. You can record injection or infusion sites, symptoms during and after a dose (cramping, nausea, chest pressure, chills or fever), and weight. Vial inventory tracks the lot number and beyond-use date on the pharmacy label, so a recall or warning letter can be matched to what you have on hand [6]. Side-effect entries can be exported to share with your prescriber.

The reference half-life in STACK

STACK ships NAD+ without a default half-life: No human elimination half-life published; plasma unchanged for 2 h. You enter your own estimate before a curve is drawn. Measured in: healthy men aged 30–55, 6 h intravenous infusion (no half-life calculated).

Estimate only. Modelled from the published half-life you selected and the doses you logged — not a measured blood level. Do not use it to make medication decisions.

Free tools for NAD+

Read next

Sources

Every URL below was fetched and checked on 2026-09-24. Bracketed numbers in the text link here.

1. TrialA Pilot Study Investigating Changes in the Human Plasma and Urine NAD+ Metabolome During a 6 Hour Intravenous Infusion of NAD+ (Grant et al. 2019)
2. OtherIntravenous infusion of NAD+ versus nicotinamide riboside (NR): a retrospective tolerability pilot study in a real-world setting (Reyna et al. 2026)
3. FDABulk Drug Substances Nominated for Use in Compounding Under Section 503A (updated May 14, 2026)
4. FDABulk Drug Substances Used in Compounding Under Section 503A of the FD&C Act
5. FDAAmendments to the List of Bulk Drug Substances That Can Be Used to Compound Drug Products in Accordance With Section 503A (proposed rule, Sep 5 2019)
6. FDAWarning Letter: GenoGenix LLC (Jan 20 2026)
7. FDACompounding and the FDA: Questions and Answers