NMN vs. NR

By now, you’ve heard of NAD+. Members of our medical review board have told us they consider it a rising star in the health and wellness space. Even in the fickle forums of social media, it has shown lasting power as a subject of short- and longer-form videos. Its principal appeal is that it can enhance your cellular function and thereby stave off the effects of aging — evidently a popular selling point, seeing as many major supplement brands now produce their own NAD+ capsules.

Yet a straight NAD+ capsule wouldn’t do you much good. It simply wouldn’t hold up through digestion, nor would it pass effectively through the plasma membrane, so the dose you swallow is nowhere near the amount that could possibly enter your cells.1 What you want instead is a bioavailable precursor, something that absorbs easily and then converts to NAD+ through your body’s natural biological processes.

Among the supplemental NAD+ precursors available, it’s nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR) that stand out for their combination of efficacy and relatively small side effect profiles. We’ve tried numerous supplements featuring these precursors in a variety of forms. So which precursor is better, NMN or NR?

NMN and NR are interrelated, and both reliably feed the pathway that leads to NAD+, but they enter the pathway at different points, and each has demonstrated health benefits in clinical research that the other (so far) hasn’t. This table illustrates:

If you only have budget for a supplement that offers one of those precursors, we would recommend NMN as the slightly better option, though NR offers a compelling health benefit that NMN has yet to produce in clinical research. We cover these topics, as well as others, in this guide.

Notice that NR must first convert to NMN on its trajectory toward NAD+. NMN’s closer “distance” to NAD+ is one reason why we feel it’s the slightly better NAD+ precursor. The other reason is its larger set of clinically exhibited health benefits to date. Unless your goal is a very low-dose supplement or neuroprotection is the only additional benefit you want, NMN will give you more anti-aging benefit for your buck.

Based on our research, though, the best NAD+ boosting supplement is one that combines NMN and NR in a complex with supporting ingredients that can keep the precursors performing as they should beyond just the short term. As we discuss later in this guide, taking the precursors in combination may help you take advantage of your body’s natural processes so that you can more efficiently produce NAD+ and bolster your mitochondrial function.

Over the past two decades, Innerbody Research has helped tens of millions of readers make more informed decisions about staying healthy and living healthier lifestyles.

Our interest in NAD+ and its precursors has grown alongside that of the medical, science, and supplement-using communities. To date, we’ve dedicated nearly 1,300 cumulative hours to understanding the coenzyme’s role in human health and aging, and we’ve closely read more than 200 scholarly sources on the subject. We continue to learn, too, as we monitor the NAD+ boosting space and further high-quality studies enter the literature.

Additionally, like all health-related content on this website, this guide was thoroughly vetted by members of our Medical Review Board for accuracy and will continue to be monitored for updates by our editorial team.

Before we can discuss NMN and NR, we first have to contextualize them with regard to NAD+.

The term NAD, or nicotinamide adenine dinucleotide, encompasses two molecules:

• NAD+: the oxidized form, which takes electrons and protons from hydrogen to become NADH
• NADH: NAD with hydrogen, the reduced form, which releases electrons in a process that fuels cellular energy production

NAD+ is the form we refer to when we talk about NAD’s influence on longevity and healthspan. That’s because it’s the form that directly regulates reactive oxygen species, which would otherwise degrade your mitochondria, damage your DNA, and increase your risk for diseases we normally associate with aging — diabetes, liver disease, heart disease, cancer, and Alzheimer’s, to name a few.2 It’s also the form being actively consumed by your body’s enzyme systems, allowing NADH to outbalance NAD+ over time, in turn raising your risk for the diseases we’ve just mentioned. Therefore, you need sufficient NAD+ to retain the balance, keep your cells functioning efficiently, and fend off pathologies that can diminish your health and cut your life short.

NMN is nicotinamide mononucleotide, one of the fundamental building blocks of the nucleic acids, DNA and RNA. NR is nicotinamide riboside, a form of vitamin B3. Both are NAD+ precursors, meaning that they eventually become NAD+ in cells. If you take either one as a supplement, the ultimate effect is that your NAD+ levels increase (as long as other players in NAD+ metabolism remain in fine working order — more on that later). Generally, having more NAD+ is a boon to your mitochondrial health, which is in turn the bane of cardiovascular, neurodegenerative, and other age-related diseases.3 2

Besides their ability to increase circulating NAD+, NMN and NR have each exhibited specific health benefits that the other has yet to replicate in clinical research:

How NMN and NR become NAD+

NMN and NR become NAD+ by a metabolic process called the salvage pathway, which also involves another form of B3 called niacinamide (NAM, a.k.a. nicotinamide). The term salvage refers to how the by-products of NAD+ consumption by your cells can be “saved” and converted back into NAD+ in a recyclable fashion. That being the case, it’s less of a straight pathway, with beginning and terminal ends, than it is a loop.

At any rate, around 85% of your body’s total NAD+ is produced through the salvage pathway (the remainder being accounted for by the Preiss-Handler and de novo synthesis pathways).11 The process by which this occurs involves a lot of enzymes, several of them having similar-sounding abbreviations. In the simplest (but still thorough) terms, it goes like this:12

1. B3 to NMN: NAM from dietary sources is converted to NMN by the enzyme nicotinamide phosphoribosyltransferase (NAMPT). Meanwhile, NR enters the picture via equilibrative nucleoside transporters (ENTs) and is likewise converted to NMN by enzymes called nicotinamide riboside kinases 1 and 2 (NRK1 and NRK2).
2. NMN to NAD+: We now have NMN from both NAM and NR. This NMN is subsequently acted upon by a group of enzymes called nicotinamide mononucleotide adenylyltransferase (NMNAT), ultimately yielding NAD+.
3. NAD+ consumption: Several other enzymes (whose abbreviations are many, and which we’ll spare you) put your NAD+ to use in areas such as DNA repair, sleep regulation, inflammation control, and mitochondrial function. NAM is left over as a by-product.
4. Back to the beginning: While some of the leftover NAM can be metabolized and excreted from your body, much of it is instead recycled via the salvage pathway to restart the process.

In another guide (“NMN vs. NAD”), we likened the salvage pathway to a donut shop: any dough that isn’t cut to shape can be kneaded back together and rolled out again, all while fresh dough is being turned out. But as with a donut shop, production capacity is finite. Without proper resource management, there comes a point when production goes down.

Resource management: The role of support players

A donut shop needs power to run the equipment and protocols in place to prevent pests and theft. The same goes for the salvage pathway, especially as you get older.

Remember, when NAD+ is consumed within a cell, it’s broken back down into NAM. Older cells tend toward excessive NAD+ consumption, resulting in higher levels of NAM. Meanwhile, advanced age also correlates with reduced expression of NAMPT, the enzyme that converts NAM to NMN. The consequence: too much NAM.13 To manage the excess, your cells increase levels of the enzyme nicotinamide N-methyltransferase (NNMT) to convert NAM to methylnicotinamide. The increase in NNMT expression can potentially spur tumor progression, while methylnicotinamide can lead to mitochondrial dysfunction, which is implicated in the pathogenesis of insulin resistance, coronary artery disease, and Parkinson’s.14 15 Molecules called methyl groups can prevent this woeful accumulation by shuttling leftover NAM back into the salvage pathway, as well as by converting excess NAM to excretable meNAM, but your pool of methyl groups is limited and can quickly become depleted.

What we mean, then, by “resource management” is the proactive use of other supplements to:

• Top off your methyl pool: Methyl donor supplements reinforce your team of methyl groups. They’re the backup power source to your NAD+ production machinery. Among the available choices, trimethylglycine (TMG, a.k.a. betaine) is one of the best.
• Intervene in NNMT expression: By suppressing the expression of NNMT, you can prevent a significant portion of NAM’s conversion to harmful methylnicotinamide and hence slow the rate at which your methyl pool is depleted. One supplement to consider here is spermidine, which has a negative-correlational effect on NNMT.16

Administered orally, even high-dose NMN (1,200mg per day) and NR (2,000mg per day) have been found to be well-tolerated in clinical research lasting six weeks.17 18 Safety studies tend to report no serious or statistically significant adverse events.19 In the short term, then, both NAD+ precursors ought to be safe for the general population.

Their long-term safety is more uncertain. Remember what we said about topping off your methyl pool and intervening in NNMT expression. Should you neglect to follow through on these resource management practices, you could see yourself with an elevated risk for tumorigenesis and mitochondrial dysfunction.

In addition, some researchers have theorized that NAD+ boosting may be an inherent cancer risk on the basis that NAD+ improves the function and efficiency of all cells, including malignant ones. Indeed, in a 2021 publication, the authors state that:20

• NAD has “already been implicated in various cancers, as cancer requires vast energy to proliferate”
• “High levels of NAD bestow therapy resistance to cancers”
• “Higher levels of NAD may cause tumors to be more potent”
• And “starving cancer of NAD and from the enzymes found in the myriad of NAD pathways may also hold merit in the fight against slowing further cancer progression”

At the same time, other research has posited that higher NAD+ levels have an inverse relationship with cancer, with a 2023 study in particular finding that “NAD [supplementation] suppresses tumor metastasis.”21

So, what’s the verdict — does NAD+ boosting prevent cancer or promote it?

There’s currently no consensus on the matter, but it could be that both things hold true under different circumstances: it might prevent initial tumor development in a cancer-free body, but also feed tumor growth when cancer is already present. If that’s the case, people with a personal or familial history of cancer might do well to pass on NAD+ boosting, or at least have a thorough discussion with a doctor to determine whether it’s appropriate for them.

Is NMN banned in the United States?

Some people may have heard that NMN was banned by the U.S. Food & Drug Administration (FDA) and assume that it was due to safety concerns. In truth, NMN was previously prohibited but is no longer so, and the cause of the prohibition had nothing to do with safety.

What happened was that NMN was being studied as an Investigational New Drug (IND), and as such, it could no longer be designated as a dietary supplement and would need FDA authorization for administration in humans.26 27 The prohibition was subsequently met with a lawsuit that led to a federal court ruling in 2024 that suspended legal proceedings on the case and allowed NMN to continue being sold as a supplement, at least for now.

With the goal of increasing NAD+ levels, either NMN or NR will succeed. Ideally, you would take them together in a complex formulated with support ingredients that can offset the potential long-term downsides. Remember, a sustained NAD+ boost promotes mitochondrial health and efficient cellular energy production, but high NAD+ can lead to excess NAM over time, which in turn increases the expression of an enzyme (NNMT) that can elevate your risk for age-related disease pathologies. Ingredients like TMG and spermidine can help prevent a good thing from going awry.

But if you could pick only one, NMN may be the better option for most people. That’s because it has demonstrated a broader range of secondary benefits in clinical research — those related to insulin sensitivity,4 mitochondrial function,5 weight,6 eye function,7 sleep,8 and telomeres9 — compared to NR’s neuroprotectant action.10

With that being said, “better” ultimately depends on your health goals. If something like Alzheimer’s is your primary age-related health risk, then NR might look like the superior NAD+ precursor.

Whether you choose NMN, NR, or both, we’d advise you not to neglect those other supportive ingredients (such as a good methyl donor) to ensure that your longevity efforts do not actually become counterproductive.

Whether you choose NMN, NR, or a complex with both, you’ll want to know how to identify a good supplement when you see one.

Broadly speaking, the best NMN/NR supplements share these qualities:

The dose recommendations here are based on studies that have yielded increased NAD+ levels from the stated quantities. Understand, however, that higher doses are better, just as long as they’re under the maximum thresholds for safety. With something like 700mg of NMN or 400mg of NR, you stand to see even larger increases in your circulating NAD+ without testing the limits of your tolerance. Also, although the body of literature has little to say about combining NMN and NR, these precursors’ different entry points in the salvage pathway suggest that taking them together may help you achieve the highest possible NAD+ boost.

Regarding those supporting ingredients, you specifically want them to prevent depletion of your methyl pool. A methyl donor like TMG (minimum 500mg) will do the job directly, while something like spermidine (minimum 15mg) can boost by-products that eventually lead to increases in another methyl donor.24

And as for third-party testing, that’s a matter of good prudence. Stanford Lifestyle Medicine puts it like this: “When it comes to supplements, third-party testing is a gold standard for ensuring product safety and efficacy.”25 That is, when an independent lab analyzes a product and verifies its composition, you can be sure you’re getting the ingredients and doses listed on the label.