NAD+ buying guide
What is NAD+? The coenzyme every living cell runs on
NAD+ (nicotinamide adenine dinucleotide) is a coenzyme found in every living cell, where it carries electrons through the reactions that release energy from food and is used up by enzymes that repair DNA. In people, supplements that feed it raise blood levels reliably, but trials haven’t shown that a higher level improves health.
What NAD+ does in the body
NAD+ is short for nicotinamide adenine dinucleotide. The National Library of Medicine files it among the coenzymes and describes it as “found widely in nature” and “involved in numerous enzymatic reactions”. A 2015 brain-imaging study put the reach of it plainly: NAD “exists in NAD(+) or NADH form in all living cells.”
It does two kinds of work. In one, it’s a carrier, picking up electrons in one reaction and handing them on in the next, which is how a cell moves energy out of the food it burns. In the other, it’s raw material that enzymes consume.
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| Job | What happens | Described in |
|---|---|---|
| Carrying electrons | It takes up electrons and becomes NADH, then hands them on and becomes NAD+ again, over and over, in the reactions of energy metabolism | MeSH; PLoS One 2012; Rejuvenation Research 2019 |
| DNA repair | It is the only substrate of PARP, a DNA-repair enzyme in the cell nucleus, which uses it up | PLoS One 2012 |
| Sirtuins | It is used up by sirtuins, enzymes that regulate gene expression and metabolism according to the cell’s energy state | PLoS One 2012; Rejuvenation Research 2019; J Clin Endocrinol Metab 2016 |
| Signaling | It takes part in messenger signaling inside the cell through the enzyme CD38 | Rejuvenation Research 2019 |
Carrying electrons recycles the molecule. PARP and the sirtuins use it up as their substrate, which is why a cell keeps rebuilding NAD+ and why the question of supply comes up at all.
Source: MeSH descriptor NAD, U.S. National Library of Medicine; PLoS One 2012, PMID 22848760; Rejuvenation Research 2019, PMID 30124109; J Clin Endocrinol Metab 2016, PMID 26574954. Documents read in September 2026.
The second kind of work is why anyone talks about running low. PARP, the enzyme that repairs damaged DNA, uses NAD+ as its only substrate, and so does the sirtuin family. In a 2012 study of human skin, PARP activity climbed with age in men and ran opposite to tissue NAD+: the more the repair enzyme was working, the less NAD+ was left. The authors read that as damage accumulating with age and drawing NAD+ down. It’s a hypothesis their data support, not a proven cause.
NAD+ and NADH are one molecule in two states
The plus sign isn’t branding. MeSH defines NAD as an electron carrier that works “by being alternately oxidized (NAD+) and reduced (NADH).” NAD+ is the form ready to accept electrons; NADH is the same molecule carrying them. A cell needs both, and the balance between them is its own measurement, called the redox state.
That balance changes how a study should be read. The 2015 brain study found NAD+ lower and NADH higher in older volunteers, and total NAD lower as well. So part of the decline was real loss, and part of it was the balance tipping toward NADH. A 2019 plasma study reported the same tilt.
Both forms are sold, and both sit in the same place on FDA’s compounding list: NAD and its reduced form, NADH, are in Category 1, “Bulk Drug Substances Under Evaluation”.
Does NAD+ fall with age? It depends where you measure
In tissue, yes. In blood, the two largest studies disagree, and one of them says it doesn’t fall at all.
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| Study | What was measured, in whom | What it found |
|---|---|---|
| PLoS One 2012 | Skin removed during unrelated surgery, from 49 people aged newborn to 77 | Lower with age, in men and in women |
| PNAS 2015 | The brain, by magnetic resonance scan, in healthy volunteers | NAD+ lower with age, NADH higher |
| Rejuvenation Research 2019 | Blood plasma from healthy adults aged 20 to 87 | NAD+ lower with age, NADH higher |
| Frontiers in Endocrinology 2022 | Whole blood from 1,518 adults | Lower with age in men only; no difference across age groups in women |
| Nature Metabolism 2026 | Whole blood, across seven independent cohorts | Stable with age, and across lifestyle interventions |
The tissue studies and the largest blood studies disagree, and they are not measuring the same thing. The 2026 authors write that their result challenges the use of blood NAD+ as a biomarker of aging at all.
Source: PLoS One 2012, PMID 22848760; PNAS 2015, PMID 25730862; Rejuvenation Research 2019, PMID 30124109; Frontiers in Endocrinology 2022, PMID 35388296; Nature Metabolism 2026, PMID 42135539. Each row says what that study’s own abstract says. Documents read in September 2026.
The tissue results are consistent. Skin from 49 surgical patients showed a strong negative correlation between NAD+ and age in both sexes (r = −0.706 in men, −0.537 in women). An MR scanner found less NAD+ in older brains. Plasma from adults aged 20 to 87 showed NAD+ lower in the older ones.
Blood is messier. A community study of 1,518 adults found whole-blood NAD+ falling with age in men, mostly in middle age, and no difference across age groups in women. Then in 2026 a team measured seven independent cohorts with a “rigorously validated” mass-spectrometry method and found whole-blood NAD+ “remarkably stable with age”. A 2025 review had already warned that an age-related decline in people “has been consistently observed only in a limited number of studies.”
So NAD+ falls in some tissues as people age, and whole blood may not show it. The 2026 authors go further and question whether blood NAD+ is a useful marker of aging at all.
What it’s used for, and what’s been tested in people
As a product, NAD+ is taken for anti-aging and wellness; those are the words a 2026 systematic review of the field put in its title. It lists the ways people try to raise it, from lifestyle changes and supplements to, “in some wellness settings, parenteral NAD⁺ administration”, which means NAD+ given by injection or drip.
Most of the human evidence is about precursors: smaller molecules, nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN), that the body turns into NAD+. How NR, NMN and NAD+ differ, and how each is sold, is its own question. What matters here is that precursors reliably move the number. Nicotinamide riboside raised whole-blood NAD+ by 22%, 51% and 142% at three doses in an eight-week trial, and a pharmaceutical NMN produced “substantial dose-related increases in blood NAD levels.”
What a higher number does for a person is the open part. A 2026 systematic review gathered 33 human intervention studies. The precursors “consistently demonstrated biochemical target engagement”, it found, while effects on function, metabolism and blood vessels “were heterogeneous and often null or endpoint-specific.” It found no outcome trial at all of NAD+ itself given into a vein or a muscle for any anti-aging or wellness use.
Three questions come up most, and each has its own page: what has actually raised NAD+ in people, whether it helps with weight loss, and what the two human studies of an NAD+ drip report.
What’s sold as NAD+, and what it costs
Of the 382 prices in this index, from 110 sellers, 380 are for NAD+ itself rather than a precursor.
The injectable kind is compounded. NAD sits on FDA’s list of substances nominated for compounding in Category 1, “Bulk Drug Substances Under Evaluation”. While a substance sits there, FDA says it “does not intend to take regulatory action” against a pharmacy compounding with it under section 503A, provided other conditions are met. That’s a pause, not an approval: FDA hasn’t decided whether NAD belongs on the 503A bulks list itself. That same list is why NAD+ shows up beside peptides, though it isn’t one.
Prices run wide: 43 of the 110 sellers publish a standing monthly rate, and those 59 rates run from $60 to $299 a month, source readings September 2026 to October 2026; the median of them is $179. The other 67 publish some other kind of figure, such as a floor, a first-month price or a prepay total, or nothing that resolves to a price, and those kinds aren’t interchangeable. The 43 sellers with a standing rate are laid out one by one on the NAD+ price index, and every figure any seller prints is on that seller’s review page.
What’s still unknown about NAD+
None of these has an answer yet.
What is a normal NAD+ level, and is yours low? No reference range exists that a person could hold a test result against.
A validated reference range for NAD+ in a sample a clinic can actually take, tied to a health outcome. The two largest blood studies disagree about age: 1,518 people in one community cohort showed a decline in men only, and seven cohorts measured in 2026 showed whole-blood NAD+ holding steady with age, a result its authors say challenges the use of blood NAD+ as a biomarker of aging or lifestyle.
Does raising NAD+ make anyone healthier? Supplements raise the blood number reliably; whether that changes an outcome a person would notice has not been shown consistently in trials.
Larger, longer randomized trials with a clinical endpoint named in advance. A 2026 systematic review of 33 human intervention studies found the outcome results heterogeneous and often null, and found no outcome trial at all of NAD+ given by vein or by intramuscular injection.
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About this page
Nothing here is medical advice, diagnosis or treatment. This is a price index, and pages like this one exist because a reader cannot judge a price without knowing what the thing is. Talk to a licensed clinician before starting or stopping anything, and see the medical disclaimer.
Document sources read September 2026. The references below retain each source reading date and the date printed on the document itself. An editorial revision does not refresh those source records. If something here is wrong, the corrections page says how that gets fixed and what has been fixed before.
Sources
- MeSH descriptor: NAD
- In vivo NAD assay reveals the intracellular NAD contents and redox state in healthy human brain and their age dependences.
- Age-associated changes in oxidative stress and NAD+ metabolism in human tissue.
- The Plasma NAD+ Metabolome Is Dysregulated in "Normal" Aging.
- Obesity Is Associated With Low NAD(+)/SIRT Pathway Expression in Adipose Tissue of BMI-Discordant Monozygotic Twins.
- Aerobic and resistance exercise training reverses age-dependent decline in NAD+ salvage capacity in human skeletal muscle.
- Association of Human Whole Blood NAD+ Contents With Aging.
- Human whole-blood NAD+ levels do not vary with age or lifestyle interventions.
- NAD+ precursor supplementation in human ageing: clinical evidence and challenges.
- Safety and Metabolism of Long-term Administration of NIAGEN (Nicotinamide Riboside Chloride) in a Randomized, Double-Blind, Placebo-controlled Clinical Trial of Healthy Overweight Adults.
- MIB-626, an Oral Formulation of a Microcrystalline Unique Polymorph of β-Nicotinamide Mononucleotide, Increases Circulating Nicotinamide Adenine Dinucleotide and its Metabolome in Middle-Aged and Older Adults.
- NAD⁺ supplementation for anti-aging and wellness: A PRISMA-guided systematic review of preclinical and clinical evidence.
- Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the Federal Food, Drug, and Cosmetic Act
- Interim Policy on Compounding Using Bulk Drug Substances Under Section 503A of the Federal Food, Drug, and Cosmetic Act — Guidance for Industry