What is NMN: Benefits, Side Effects, and How to Take NMN Supplements

Anyone interested in the anti-aging and longevity space has probably heard people throw around the term “NMN” in recent years—but haven’t known exactly what it is or what it does. 

Despite sounding suspiciously like M&M’s, NMN has nothing to do with candy—it stands for “nicotinamide mononucleotide,” a mouthful of a compound that we know now is intricately linked to health and anti-aging properties.  

If you’ve been a bit confused about NMN and whether or not you should be taking it, we’ll fill in the gaps for you—in this article, we’ll take a deep dive into what NMN is, the potential health benefits of NMN, and any side effects of NMN supplements that you should know about.

What Is NMN?

NMN is the helpful acronym for the term nicotinamide mononucleotide—a phrase we like to avoid saying because it gets most of us tongue-tied.

While NMN is a naturally occurring molecule found in foods like avocado, broccoli, cabbage, cucumber, and edamame, NMN supplements have recently taken center stage due to their high concentration and potential to support various aspects of health.

Although NMN was discovered as a crucial metabolic compound back in 1963, longevity researchers have only recently pinpointed its anti-aging properties because of its status as a precursor to another molecule known as NAD+ (nicotinamide adenine dinucleotide).

NAD+ is a vital coenzyme—meaning, it’s a “helper” molecule that assists other enzymes to do their jobs properly—and is found in virtually every cell in the human body.

It’s involved with processes ranging from brain cell growth to repairing DNA damage to helping our mitochondria generate cellular energy from food. 

Without enough NAD+, our cells, organs, and tissues can’t function properly—and without any NAD+ in our body, we’d die almost instantly. 

Despite its essentiality, NAD+ levels decline with age, leading to accelerated aging and age-associated physiological decline, like the development of age-related diseases. 

Some research has found that NAD+ can drop by as much as 50% between the ages of 40 and 60, with an additional decline upon reaching older age. 

With NAD+ depletion, every organ system starts to run at suboptimal levels, leading to metabolic disorders like diabetes, hypertension, heart disease, cognitive decline, liver and kidney conditions, muscle loss, and more. 

So, if NAD+ is so important, many people wonder why we can’t simply supplement with NAD+ itself. 

Put simply, NAD+ in capsule form cannot easily cross over cell membranes. 

It would first have to be converted into another compound before it could be taken up by the cell and utilized—like NMN, which has been found to be a direct precursor to NAD+ and has shown promise for supporting healthy longevity.

The Top 6 NMN Health Benefits

Other than directly boosting levels of NAD+, NMN has also been studied for its effects on improving health markers associated with age-associated physiological decline.

Although most of the studies on NMN have been done with animal models or cell-based cultures, several recent trials have tested the compound’s effects in humans—and with beneficial results. 

Even though humans obviously aren’t mice, flies, or worms, these animals can serve as important initial stepping stones for health and longevity research—plus, some of them, like rodents, have surprisingly similar anatomy and genetics as us. 

More research is definitely still needed in human clinical trials—however, preclinical studies, like many of these, are still important to incorporate into an overall base of evidence on safety and how a compound or supplement works.

1. May Support Anti-Aging

Although it sounds like something out of a sci-fi movie, many people are interested in NMN and other NAD+ precursors due to their purported link to increased longevity. 

But can NMN actually support healthy aging and/or extend lifespan? 

The short answer is: we don’t know yet. 

While we don’t have that data from long-term human longevity studies (which take decades and millions to complete), animal models can provide us with some information. 

Research has found that boosting NAD+ levels through precursors like NMN can extend the lifespan of species like yeast and worms.

For example, one 2013 study published in the acclaimed journal Cell found that both NMN and another NAD+ precursor, nicotinamide riboside (NR), extended the lifespan of the commonly studied lab worm, C. elegans, by over 10%.

However, the research on NMN and lifespan in rodents and humans is still lacking—we will need many additional studies before we can state if NMN can lengthen lifespan in humans. 

Another up-and-coming area of research is how NMN or NAD+ affect markers of longevity, like sirtuin activity, DNA damage, cellular senescence, and telomere attrition. 

Sirtuins are a family of proteins nicknamed “longevity genes” that are involved in mitochondrial repair, reducing cellular senescence, regulating DNA damage, and more. 

As sirtuins are dependent on NAD+ to function, boosting NAD+ levels through precursors like NMN should support sirtuin function.

Research shows that, in mice, NMN supplements activate SIRT1—a sirtuin protein that is involved with controlling gene expression related to inflammation, energy metabolism, and cellular aging—in addition to restoring NAD+ levels (more about gene expression here).

2. Metabolic Health

In addition to acting on longevity biomarkers, NMN may increase lifespan by improving healthspan—the number of healthy years lived without developing chronic or age-related diseases. 

Metabolic disorders are increasingly prevalent in our society, including poor glucose metabolism, insulin resistance, metabolic syndrome, prediabetes, and type 2 diabetes. 

In April 2021, a trial published in Science demonstrated that NMN supplementation can improve insulin sensitivity in the skeletal muscle of prediabetic women. 

In this 10-week, randomized, placebo-controlled, double-blind trial, overweight or obese postmenopausal women who took 250mg of NMN supplements per day had significant improvements in skeletal muscle insulin signaling, in addition to increased insulin sensitivity, compared to women taking a placebo. 

As dysfunctional insulin signaling and insulin resistance (the opposite of insulin sensitivity) are implicated in prediabetes and type 2 diabetes, this research suggests that NMN may be beneficial for lowering this risk. 

Although the study was small (only 25 women), this trial was groundbreaking, as it was the first of its kind to study the metabolic effects of NMN in humans. 

Animal studies have also corroborated these findings—in 2016, a study published in Cell Metabolism found that mice who received NMN supplementation for 12 months had significantly improved insulin sensitivity.

3. May Reduce Body Weight

People with excess body fat tend to have reductions in both NAD+ levels and ATP (cellular energy) production, so it’s thought that replenishing NAD+ through NMN may help reverse this—in addition to supporting metabolic pathways—to maintain a healthy weight. 

In research with mice, supplementing with either 100 or 300 mg/kg of body weight of NMN for 12 months led to reductions in body weight by 4% and 9%, respectively, by increasing energy expenditure and oxygen consumption.  

In addition to suppressing age-associated weight gain, NMN supplementation enhanced energy metabolism and promoted physical activity—all of which are vital for healthy weight management. 

However, we don’t have research looking at weight loss and NMN in humans yet.

4. Brain Health

Reduced NAD+ levels in brain cells are thought to impair mitochondrial function and be a partial cause of declining cognitive function with age.

Therefore, replenishing NAD+ stores through NMN supplementation may prevent this dysfunction.

In research with a cell model from rats with Alzheimer’s disease, NMN has been found to inhibit a buildup of beta-amyloid plaques, which are commonly found in neurodegenerative diseases like Alzheimer’s disease. 

Plus, a study with aged mice showed that supplemental NMN led to improvements in spatial working memory, gait coordination, and neurovascular health—an important component of brain function and cerebral blood flow.

The neurovascular system is crucial for the brain to receive nutrients and oxygen through its network of blood vessels—and a decline in this system can lead to cognitive loss.

In aged mice, NMN has shown promise for improving the health and integrity of this system, leading to neurovascular rejuvenation.

But, again, we only have research on this topic in cell-based cultures and animals at this point.

5. Muscle Health and Exercise Performance

NMN supplementation may enhance muscle strength, endurance, and physical performance. 

In research from 2021, combining NMN with rigorous physical activity was found to support aerobic capacity in healthy adults in a dose-dependent manner—meaning that the higher doses of NMN (1,200mg per day in this case) produced a more significant effect than the lower doses of 300mg. 

NMN has also been found to improve muscle strength in a study with healthy Japanese men. 

In this study, older men (age 65+) who took 250mg of NMN for 12 weeks had significant improvements in lower extremity muscle strength, as measured by the 30-second chair-stand test, which counts how many times someone can go from sitting in a chair to standing (without using their arms) within a half-minute period.

They also had improvements in gait speed and left-hand grip test compared to the placebo group. 

Gait speed and grip strength are both known clinical markers of aging, as they are strong predictors of age-related muscle loss called sarcopenia. 

However, this study was relatively small and had a non-diverse sample of only healthy older Japanese men—but the results are promising for using supplemental NMN to support skeletal muscle health. 
In rodents, those that combined exercise with NMN supplementation had increased blood flow and running endurance.

6. Increased Energy Production

Lastly, NMN may help with energy levels, which makes sense because NAD+ is needed to produce cellular energy.

In a 2022 study, older adults who took 250mg of NMN per day in the afternoon had reductions in sleepiness (in addition to improvements in lower limb motor function). 

Interestingly, taking NMN in the morning did not show the same benefits.

NMN Supplements: Side Effects and Safety

Although most of the research on NMN (nicotinamide mononucleotide) has been done with animal models or cell cultures, several studies in recent years have looked at its safety in humans.

NMN appears to be a safe compound to take, as evidenced by a clinical study from 2020 that assessed the effects of a single dose of NMN in a group of ten adult Japanese men. 

A one-time administration of NMN, in doses ranging from 100 to 500 mg, was found to be safe and well-tolerated with no adverse side effects. 

The men experienced no immediate or significant changes to sleep quality, eye function, heart rate, blood pressure, oxygen saturation, or body temperature.

Overall, this study provided valuable information about the short-term safety and tolerability of NMN—however, research on long-term administration of NMN is warranted with varying ages, sexes, and ethnicities, as this sample size was small and included only healthy Japanese men between the ages of 40 and 60. 

A more recent study from April 2022 showed that healthy volunteers who received 250 mg/day of an NMN supplement for 12 weeks had no abnormalities in physiological and laboratory tests and no obvious adverse effects, sleep quality issues, etc. 

At high doses, NMN supplements may cause digestive problems, but that seems to be the only reported potential side effect thus far.

However, no long-term studies on NMN supplementation have been conducted yet.

NMN Supplements: How Much NMN Should I Take?

As NMN is a relatively new supplement, we don’t know for sure the “correct” doses to take. 

The NMN doses that have been used in the available research in humans range from 100 to 1,200mg per day.

Hopefully, in the upcoming years, more research will better elucidate a smaller range of the ideal NMN dose to take.

The most common doses seen in NMN supplements on the market today are in the range of 250mg to 750mg per day. 

There are also several methods to take NMN supplements, including powder, capsules, liposomal forms, lozenges, and even through an IV drip.

While one form isn’t necessarily better than another, they will have varying rates of absorption. 

An IV drip will be absorbed the fastest, as it bypasses the digestive tract and goes immediately into the bloodstream—however, these are the least accessible options.

Lozenges and liposomal forms absorb more quickly than powders and capsules, with powders getting a bit of a jump start due to their lack of capsule casing.

Both powders and capsules will first need to be broken down in some capacity by the stomach and intestines before reaching the bloodstream for utilization.

NMN Supplementation FAQs