What Is NAD and What Is It Used For?

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What Is NAD+ and Why Does the Body Need It?

NAD+ stands for nicotinamide adenine dinucleotide, a small molecule found inside every cell in the body. It acts as a coenzyme, meaning it works alongside enzymes to carry out chemical reactions — most notably, shuttling electrons during the process that converts food into cellular energy. Without adequate NAD+, the step-by-step chemistry that cells use to extract energy from carbohydrates and fats would not function the way it needs to.

Beyond energy metabolism, NAD+ is a required input for a family of proteins called sirtuins, which are involved in regulating cellular repair processes, and for PARP enzymes, which help manage DNA integrity. Bogan and Brenner (2008), in a biochemistry review published in the Annual Review of Nutrition, described how the body builds NAD+ through several overlapping pathways depending on which raw materials — tryptophan, niacin, nicotinamide riboside, or nicotinamide mononucleotide — are available in the diet. This is a foundational reason NAD+ is described as central to cellular function rather than tied to any single organ or system.

What Does Research Say About NAD+ and Aging?

The research most people reference when discussing NAD+ and aging is observational and mechanistic, not a demonstration that raising NAD+ changes how a person ages. Massudi et al. (2012), published in PLOS ONE, measured NAD+ levels in human tissue samples and reported that levels tend to be lower in older samples compared to younger ones. This is a measurement finding — the study did not test any intervention and did not establish that supplementation would change that trajectory.

Imai and Guarente (2014), writing in Trends in Cell Biology, reviewed how declining NAD+ availability has been connected to several markers associated with cellular aging across different studies, while Yoshino, Baur, and Imai (2018) in Cell Metabolism reviewed evidence that the total NAD+ pool (NAD+ plus its reduced form, NADH) tends to fall with age across the tissues and species examined. Both are reviews summarizing other researchers' work, not new experiments, and neither tested a human outcome from supplementation. It's accurate to say the connection between NAD+ and cellular aging markers is well documented at the level of observation and mechanism — it is not accurate to say supplementation has been shown to reverse the pattern in people.

How Does the Body Get or Make NAD+?

The body produces NAD+ through two main routes: synthesizing it from the amino acid tryptophan, or recycling it from dietary precursors such as niacin (vitamin B3), nicotinamide riboside (NR), and nicotinamide mononucleotide (NMN). Bogan and Brenner (2008) mapped out how these pathways overlap, meaning a person's NAD+ supply depends on a combination of diet, genetics, and metabolic demand rather than a single input.

Dietary sources of niacin and related precursors include foods like poultry, fish, mushrooms, and various plant foods, though the amounts of NR and NMN specifically found in whole foods are small compared to the doses studied in supplement trials. For a closer look at which foods contain NAD+ precursors and how much they realistically contribute, see NutraHack Labs' guide on whether you can get NAD+ from food. Supplement forms like NR and NMN were developed specifically because they are more efficiently converted into NAD+ than taking niacin or NAD+ itself, which the body does not absorb intact in meaningful amounts when taken orally.

NR vs. NMN: Does the Precursor Matter?

NR and NMN are both NAD+ precursors, but they have been studied separately, and no published trial has directly compared the two head-to-head for outcomes. Trammell et al. (2016), in Nature Communications, gave adults single oral doses of NR at 100, 300, and 1,000 mg and tracked how blood NAD+ metabolites responded, finding a dose-dependent rise. Airhart et al. (2017) in PLOS ONE similarly found that single oral doses of NR raised circulating precursor levels in a dose-dependent way over several hours — though neither study measured any functional or long-term benefit.

On the NMN side, Irie et al. (2020) in Endocrine Journal ran the first published human study of oral NMN, a single-arm, non-randomized trial giving single doses to ten healthy men and tracking metabolites and clinical safety measures for five hours. It found no significant adverse clinical findings and a rise in plasma NMN metabolites, but it tested no outcome beyond that window and was part-funded by a pharmaceutical company. Because the two precursors have not been tested against each other, claims that one is definitively superior go beyond what the current research supports. For a deeper comparison of the two forms, see NutraHack Labs' guide on NAD+ vs. NADH.

What Do Human Trials Show About NR Supplementation?

The most informative human trials on NR used daily doses over several weeks, not single doses, and the results were mixed rather than uniformly positive. Martens et al. (2018), published in Nature Communications, randomized 24 middle-aged and older adults to 1,000 mg/day of NR or placebo for six weeks. NAD+ metabolites rose as expected, and some cardiovascular markers changed modestly, but several other outcomes measured in the study did not differ from placebo.

Remie et al. (2020) in the American Journal of Clinical Nutrition ran a six-week NR trial in healthy adults and found that muscle NAD+ content increased, while the specific energy metabolism measures the researchers assessed showed limited change — meaning the study did not support claims about tiredness or performance improvements. Dollerup et al. (2018), in the same journal, examined 12 weeks of NR supplementation specifically in men with a higher body mass index, so its findings do not generalize to women or to people outside that study population. Taken together, these trials show NR reliably raises measurable NAD+ metabolites in blood and tissue, but the downstream functional benefits people often associate with that rise have not been consistently demonstrated in controlled human trials.

What About NMN Trials — and Why Aren't They Simple to Interpret?

NMN research has grown quickly, but much of it is short-term, safety-focused, or has notable funding ties worth knowing about. Fukamizu et al. (2022), in Scientific Reports, ran a randomized, double-blind, placebo-controlled safety study of once-daily oral NMN for four weeks in 31 healthy adults aged 20 to 65. It found no severe adverse events and no changes beyond normal physiological variation across blood, urine, and body-composition measures — but it tested safety, not benefit, and it was funded by an NMN manufacturer, with five of six authors employed by that company.

Morifuji et al. (2024) in GeroScience conducted a 12-week randomized, double-blind, placebo-controlled NMN trial in 60 older adults. Blood NAD+ and its metabolites rose, but the study's primary outcome — a stepping test — showed no difference from placebo. Two secondary outcomes, four-metre walking time and sleep-quality scores, favored NMN, but as secondary findings they carry less weight than a positive primary result would, and three of the four authors were employees of the NMN supplier. Separately, Yoshino et al. (2021) in Science reported improved skeletal-muscle insulin signaling and related gene expression in a ten-week NMN trial in women — a notable finding, but one formally contested in the same journal over baseline differences between study groups, with the original authors issuing a reply. The honest summary is that NMN research is active and some findings are encouraging, but the field includes industry funding and contested results that deserve acknowledgment rather than being glossed over.

Who Might Be Interested in NAD+ Precursor Supplements?

Adults who are interested in supporting cellular energy metabolism as part of a broader wellness routine are the typical audience for NAD+ precursor products, particularly given that tissue NAD+ levels have been observed to decline with age per Massudi et al. (2012). That said, "interested in" is different from "clinically needs" — there is no established blood test or symptom checklist indicating a person requires NAD+ precursor supplementation, and the research base, while growing, remains short-term in most published trials (typically four to twelve weeks).

People who are pregnant or nursing, under 18, or managing any diagnosed condition should speak with a healthcare provider before adding any new supplement, including NAD+ precursors, collagen peptides, or antioxidant compounds like resveratrol and CoQ10. Conze et al. (2019), in Scientific Reports, examined nicotinamide riboside chloride across several doses and durations and reported it was generally well tolerated in the populations studied — a tolerability finding, not evidence that it produces benefit for every user. Anyone taking medications, especially those affecting metabolic pathways, should also check for interactions before starting.

Where Liposomal NAD+ For Women Fits

NutraHack Labs' Liposomal NAD+ For Women is formulated with nicotinamide riboside (NR) at 300mg as its NAD+ precursor — not NMN — paired with trans-resveratrol 98% at 100mg, a combination researchers have been interested in because resveratrol is thought to interact with the same sirtuin pathways NAD+ feeds. The formula also includes hydrolyzed collagen peptides (150mg), hyaluronic acid (50mg), alpha lipoic acid (25mg), CoQ10 (5mg), and astaxanthin (5mg), delivered in a liposomal capsule format intended to support absorption. Each bottle contains 60 capsules for 30 servings.

This formulation choice reflects the fact that NR has a longer track record of controlled human dosing trials — including Trammell et al. (2016), Martens et al. (2018), and Remie et al. (2020) — compared to NMN, whose human trials are fewer, shorter, and in some cases funded by the companies supplying the ingredient. For readers deciding between delivery formats, NutraHack Labs also offers a comparison of liposomal NAD+ liquid vs. capsules, and a separate formulation, Liposomal NAD+ Resveratrol, is available for those not specifically seeking the women's-formula blend.

How Long Does It Take to Notice a Difference?

Published trials measuring NAD+ metabolite changes from NR have generally tracked results from single doses within hours (Trammell et al. 2016; Airhart et al. 2017) up through six-week daily dosing periods (Martens et al. 2018; Remie et al. 2020), with the 12-week Dollerup et al. (2018) trial representing one of the longer NR studies in the published record. This means the research timeline for measurable metabolite changes is well documented, but it does not translate into a guaranteed personal timeline for any subjective experience, since the trials largely measured blood and tissue chemistry rather than how participants felt day to day.

For a full breakdown of what the published timelines show and what they don't, NutraHack Labs has a dedicated guide: How Long Does NAD+ Take to Work? The short version is that individual response varies, consistency in daily use matters more than any single dose, and expectations should be set by what the controlled trials actually measured rather than anecdotal reports.

Frequently Asked Questions

What is NAD and what is it used for in the body?

NAD+ is a coenzyme present in every cell that helps convert nutrients from food into usable cellular energy and supports enzymes involved in cellular repair and DNA maintenance. It is not a single-purpose molecule — it's involved in hundreds of reactions across nearly every tissue, which is why researchers describe it as foundational to basic cell function rather than linked to one organ system.

Does NAD+ decline with age?

Research measuring NAD+ in human tissue, including Massudi et al. (2012), has found lower levels in older tissue samples compared to younger ones, and reviews by Imai and Guarente (2014) and Yoshino, Baur, and Imai (2018) describe this pattern across multiple tissues and species. These are observational and review findings, not evidence that any particular supplement reverses the decline.

Is NMN or NR better for raising NAD+?

Both have been shown in separate studies to raise NAD+ metabolites, but no published trial has directly compared NR and NMN against each other for the same outcome. NR has a longer published record of multi-week, placebo-controlled dosing trials, including Martens et al. (2018) and Remie et al. (2020), while much of the NMN research to date is shorter-term or funded by companies supplying the ingredient.

Can I get enough NAD+ precursors from food alone?

Foods containing niacin and related precursors — such as poultry, fish, and certain plant foods — contribute to the body's NAD+ supply, but the concentrations of NR and NMN specifically found in whole foods are much lower than the doses used in published supplement trials. NutraHack Labs' guide on getting NAD+ from food breaks down the research on this gap in more detail.

Are NAD+ precursor supplements well tolerated?

Conze et al. (2019) examined nicotinamide riboside chloride across several doses and durations and reported it was generally well tolerated in the populations studied. Fukamizu et al. (2022) similarly found no severe adverse events over four weeks of NMN use in healthy adults, though both studies were relatively short and should not be read as proof of long-term safety for every user.

Who should check with a healthcare provider before trying NAD+ supplements?

Anyone who is pregnant or nursing, under 18, managing a diagnosed condition, or taking prescription medications should talk to a healthcare provider before starting NR, NMN, or related formulations. This also applies to co-ingredients like resveratrol, CoQ10, or alpha lipoic acid, since interactions can occur even with ingredients generally regarded as well tolerated.

If you're deciding whether an NAD+ precursor formula fits your routine, take a closer look at what's inside NutraHack Labs' Liposomal NAD+ For Women, including its full ingredient list and serving details, before making a decision.

* These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.