Does NMN Reduce Inflammation? What the Evidence Shows

Few supplements have generated more interest in longevity and wellness circles over the past decade than NMN. Researchers who study the biology of aging describe it as a way to replenish a coenzyme called NAD+ that the body makes less of as it gets older. That age-related decline in NAD+ is increasingly understood to be one of the drivers of chronic, low-grade inflammation, the kind that does not produce obvious symptoms but contributes to a wide range of age-associated conditions. Understanding whether NMN can meaningfully push back against that inflammatory trend requires looking carefully at three different bodies of evidence: the underlying biology, the preclinical animal research, and the emerging human trial data.

Why NAD+ Decline Connects to Inflammation

NAD+ is a coenzyme your cells cannot function without, and its decline with age is measurable and consequential. The body uses NAD+ in hundreds of biochemical reactions, from generating energy in the mitochondria to repairing broken DNA strands. One of its most important roles is serving as the fuel source for a family of enzymes called sirtuins. Sirtuins are often described as longevity proteins because they regulate gene expression, protect mitochondrial function, and modulate the immune system. Without adequate NAD+, sirtuins cannot do their jobs.

The connection between falling NAD+ and rising inflammation runs through a protein called NF-kB. NF-kB is the master transcription factor that switches on inflammatory genes when the immune system detects a threat. Under healthy, well-nourished conditions, sirtuin 1 (SIRT1) holds NF-kB in check by preventing it from entering the cell nucleus and activating those genes. When NAD+ levels fall and SIRT1 activity drops as a result, that brake on NF-kB weakens. The consequence is a shift toward a more inflammatory state even in the absence of any acute infection or injury. This background hum of inflammation, which researchers sometimes call inflammaging, is now recognized as a central mechanism in aging and in conditions like heart disease, type 2 diabetes, and neurodegeneration.

NMN enters the picture because it is one of the most efficient ways to raise NAD+ levels. The body can make NAD+ from several raw materials, including the amino acid tryptophan and various forms of vitamin B3, but NMN is a direct precursor in the biosynthesis pathway that sits just one enzymatic step away from NAD+ itself. Oral NMN is absorbed in the small intestine and converted rapidly, and multiple human trials have now confirmed that supplementation produces substantial, dose-dependent increases in blood NAD+ concentrations. The question is whether that rise in NAD+ is large enough, and targeted enough, to meaningfully reduce inflammatory signaling in people.

What the Preclinical Evidence Shows

Animal studies provide some of the most detailed evidence for NMN as an anti-inflammatory agent, and the results are consistent across different inflammatory models. In a 2022 study published in The Journal of Surgical Research, researchers used a mouse model of acute lung injury, one of the most severe inflammatory states tested in preclinical research. Animals given NMN showed significantly reduced levels of TNF-alpha, IL-1beta, and IL-6 in their lung fluid compared with untreated injured animals. The authors found that NMN worked by reducing the phosphorylation of p38 MAPK and p65 NF-kB, two proteins that are central to turning on the inflammatory response. NMN also reduced neutrophil infiltration into the lungs and attenuated oxidative stress, suggesting it was addressing inflammation through multiple pathways simultaneously (Tian et al., 2022).

A 2023 study in rats with traumatic brain injury found a remarkably similar pattern. Traumatic brain injury is associated with severe neuroinflammation, including activation of microglia (the brain's resident immune cells) and a surge of inflammatory cytokines. NMN administration in injured rats significantly reduced microglial and astrocyte activation, suppressed the expression of IL-6, IL-11, and other inflammatory signals, and reversed the activity of several inflammatory signaling pathways including NF-kB and JAK-STAT. RNA sequencing of brain tissue showed that inflammatory response was the most significant biological process reversed by NMN treatment. The authors concluded that NMN's protective effects worked through a TLR2/4-NF-kB signaling mechanism (Zhu et al., 2023).

A study in mice exposed to ultraviolet B radiation, a well-established model of oxidative stress and skin inflammation, added further detail. Animals treated with NMN showed reduced production of pro-inflammatory cytokines in both skin and liver tissue. The anti-inflammatory effect appeared to involve NMN activating the AMPK signaling pathway, which in turn suppressed NF-kB activity and increased levels of anti-inflammatory IL-10. Treated animals also maintained more normal skin structure and collagen levels, suggesting that the anti-inflammatory effects translated into tissue-level protection (Zhou et al., 2021).

The consistent thread across these animal studies is the NAD-SIRT1-NF-kB axis. Restoring NAD+ with NMN re-energizes sirtuin activity, which then suppresses inflammatory gene transcription. Whether an animal is experiencing lung injury, brain trauma, or UV-induced oxidative stress, the downstream result tends to be lower levels of the same handful of inflammatory markers: TNF-alpha, IL-1beta, and IL-6. These are not obscure laboratory measures. They are the same cytokines that drive much of the chronic, low-grade inflammation associated with aging and metabolic disease in humans.

What the Human Trial Data Actually Shows

Human trials on NMN have grown rapidly in number over the past few years, and they have answered one question clearly: oral NMN is safe, well-tolerated, and reliably raises NAD+ in people. A 2022 randomized, double-blind, placebo-controlled multicenter trial published in GeroScience enrolled 80 middle-aged healthy adults and randomized them to daily doses of 300 mg, 600 mg, or 900 mg NMN, or placebo, for 60 days. Blood NAD+ concentrations increased significantly and dose-dependently in all NMN groups at both day 30 and day 60 compared with placebo, with the largest increases at 600 mg and 900 mg daily. All three NMN doses were well tolerated with no safety concerns. The trial also found significant improvements in physical performance on a six-minute walking test and no significant worsening of a biological age score, while the placebo group showed a significant increase in estimated biological age over the same period (Yi et al., 2022). This trial did not measure inflammatory markers like CRP directly, but it established that the doses and duration needed to drive meaningful NAD+ increases are feasible in free-living adults.

A clinical trial from Brigham and Women's Hospital and Harvard Medical School tested a formulated version of NMN called MIB-626 in overweight and obese middle-aged and older adults. Participants received 2 grams per day of NMN (two 500 mg tablets twice daily) or placebo for 28 days. NMN substantially increased blood NAD+ and its metabolites. The NMN group also showed significant reductions in body weight (average 1.9 kg), diastolic blood pressure, total cholesterol, and LDL cholesterol compared with placebo, all of which are factors that independently influence inflammatory load. While this trial did not report CRP or other direct inflammatory markers as primary outcomes, the cardiometabolic improvements it observed are the kind that typically track with lower systemic inflammation over time (Pencina et al., 2023).

The most direct human evidence for anti-inflammatory effects from NAD precursor supplementation comes from a study using nicotinamide riboside (NR), a related molecule that raises NAD+ by a slightly different biosynthetic route. A randomized, double-blind, placebo-controlled crossover trial published in Cell Reports gave 12 older men 1 gram of NR daily for 21 days. NR elevated the skeletal muscle NAD+ metabolome and, notably, depressed levels of circulating inflammatory cytokines. RNA sequencing revealed NR-mediated downregulation of energy metabolism and mitochondria pathways, and the researchers specifically identified anti-inflammatory effects as one of the key biological signatures of NAD augmentation in aged human muscle (Elhassan et al., 2019). NR and NMN are not identical molecules, but both raise NAD+ through overlapping pathways, and this trial provides meaningful indirect evidence that restoring NAD+ in aging humans does produce measurable anti-inflammatory effects in at least some tissue compartments.

The honest assessment of the human data is that it points in the right direction but is still early. No large, long-term, placebo-controlled trial has yet been published specifically measuring CRP or other standard inflammatory markers as a primary outcome of NMN supplementation. The trials that have been done are mostly short (four to twelve weeks), small to medium in size, and focused on safety, NAD+ levels, and broad functional outcomes. That is a reasonable place to be for a relatively new supplement category, but it means the case for NMN as an anti-inflammatory agent in humans rests more on mechanistic plausibility and preclinical consistency than on the kind of definitive human trial evidence that exists for, say, omega-3 fatty acids or aspirin.

The Inflammaging Connection

One reason researchers are especially interested in NMN as an anti-inflammatory tool is the specific context of aging. The chronic, low-grade inflammation that accumulates over decades, sometimes called inflammaging, is not like the acute inflammation you feel when you sprain an ankle. It is quieter, more diffuse, and harder to detect without biomarkers. CRP levels tend to drift upward with age, tracking this background inflammatory state, and elevated CRP in midlife and beyond is associated with a higher risk of cardiovascular events, cognitive decline, frailty, and all-cause mortality. The fact that NAD+ also declines with age, and that NAD+ depletion mechanistically promotes the very NF-kB-driven inflammation that characterizes inflammaging, makes NMN an interesting candidate for addressing this specific pattern.

A 2025 review in Antioxidants examined the intersection of NAD+ metabolism, inflammation, and aging, highlighting how biomarkers including NMN and CRP may together support personalized nutrition strategies for age-related decline in muscle function. The review noted that nicotinamide supports NAD+ metabolism and activates sirtuin pathways involved in autophagy and the maintenance of muscle stem cells, with downstream effects on the inflammatory cytokine environment in aging tissue. Pyridoxine (vitamin B6) was discussed alongside nicotinamide as a complementary micronutrient that helps regulate inflammatory cytokines through different pathways (Nowacka et al., 2025). This kind of integrative perspective reflects where the science is heading: understanding NMN not as a single-target anti-inflammatory drug but as a way to support the metabolic infrastructure that keeps inflammation in check across many systems.

Practical Considerations for NMN Supplementation

For people considering NMN, the safety profile is reassuring based on trials conducted to date. A 2022 study published in Scientific Reports conducted a formal safety evaluation of 1,250 mg of oral NMN once daily for four weeks in 31 healthy men and women aged 20 to 65. No severe adverse events were observed, and clinical measurements including blood work, anthropometry, and body composition showed no changes exceeding normal physiological variation. The authors concluded that this dose, which is higher than what is commonly sold in consumer supplements, was safe and well tolerated (Fukamizu et al., 2022). Doses in clinical trials range widely from 250 mg to 2,000 mg per day, with the most commonly studied range being 300 mg to 900 mg.

NMN is not cheap, and the cost matters for anyone evaluating whether it makes sense as a long-term supplement. High-quality NMN can run anywhere from roughly $50 to over $150 per month depending on dose and brand, which puts it in a different category from inexpensive anti-inflammatory staples like fish oil or magnesium. The question of whether the anti-inflammatory payoff, which is real in animal models and mechanistically plausible in humans but not yet confirmed by large human trials, justifies that cost is genuinely individual. For someone already getting adequate sleep, eating an anti-inflammatory diet, exercising regularly, and managing stress, the incremental benefit of adding NMN is uncertain. For someone interested in longevity-focused supplementation with a reasonable safety profile, NMN is a more defensible choice than many alternatives on the market.

NMN is also one of the few supplements where the framing of "talk to your healthcare provider" is not just a regulatory boilerplate but genuinely useful advice. Because NAD+ metabolism intersects with DNA repair and cell cycle regulation, there are open questions about NMN supplementation in people who have or have had certain cancers, and some researchers have raised theoretical concerns worth discussing with a physician. For otherwise healthy middle-aged or older adults focused on general wellness, these concerns are speculative rather than established, but they illustrate why individualized medical context matters when evaluating a supplement with systemic biological effects.

How This Fits Into Tracking Your Inflammation

Understanding where your inflammatory baseline sits is genuinely useful if you are exploring NMN or any other supplement for its anti-inflammatory properties. CRP is the most widely validated biomarker of systemic inflammation, and testing it before and after any dietary or supplementation change tells you whether that change is actually moving the needle for your particular body. The existing animal evidence and the emerging human literature both suggest NMN can reduce inflammatory signaling, but the average effect in a healthy adult is not going to be dramatic, and whether you personally respond will depend on your baseline NAD+ status, your overall inflammatory load, and a range of individual factors. Watching CRP over time gives you real data to work with rather than relying entirely on what population-level research predicts. CRP is a general wellness marker rather than a diagnostic test, so any persistent elevations are best discussed with a healthcare provider who can put them in context.

Sources

• Tian Y, Zhu CL, Li P, et al. Nicotinamide Mononucleotide Attenuates LPS-Induced Acute Lung Injury With Anti-Inflammatory, Anti-Oxidative and Anti-Apoptotic Effects. The Journal of Surgical Research, 2022. pubmed.ncbi.nlm.nih.gov/36347171
• Zhu X, Cheng J, Yu J, et al. Nicotinamide mononucleotides alleviated neurological impairment via anti-neuroinflammation in traumatic brain injury. International Journal of Medical Sciences, 2023. pubmed.ncbi.nlm.nih.gov/36860678
• Elhassan YS, Kluckova K, Fletcher RS, et al. Nicotinamide Riboside Augments the Aged Human Skeletal Muscle NAD+ Metabolome and Induces Transcriptomic and Anti-inflammatory Signatures. Cell Reports, 2019. pubmed.ncbi.nlm.nih.gov/31412242
• Yi L, Maier AB, Tao R, et al. The efficacy and safety of beta-nicotinamide mononucleotide (NMN) supplementation in healthy middle-aged adults: a randomized, multicenter, double-blind, placebo-controlled, parallel-group, dose-dependent clinical trial. GeroScience, 2022. pubmed.ncbi.nlm.nih.gov/36482258
• Pencina KM, Valderrabano R, Wipper B, et al. Nicotinamide Adenine Dinucleotide Augmentation in Overweight or Obese Middle-Aged and Older Adults: A Physiologic Study. The Journal of Clinical Endocrinology and Metabolism, 2023. pubmed.ncbi.nlm.nih.gov/36740954

Frequently Asked Questions

Does NMN reduce inflammation?

Preclinical animal studies consistently show that NMN reduces pro-inflammatory cytokines including IL-6, IL-1beta, and TNF-alpha by restoring NAD+ and activating sirtuin-mediated suppression of NF-kB signaling. Human trials confirm that oral NMN raises NAD+ levels safely, and a related NAD precursor (nicotinamide riboside) was shown to depress circulating inflammatory cytokines in older adults. Direct evidence that oral NMN lowers CRP specifically in humans is still limited, but the mechanistic and preclinical case is strong.

How does NMN affect inflammatory markers like CRP?

NMN raises NAD+, which activates sirtuins such as SIRT1. Active SIRT1 suppresses NF-kB, the transcription factor that drives the release of pro-inflammatory molecules including those that trigger CRP production in the liver. Animal studies show NMN can meaningfully lower CRP-related inflammatory cytokines through this pathway. Human trials focused on NMN's cardiometabolic effects show reductions in body weight, blood pressure, and cholesterol, all of which tend to correlate with lower inflammatory burden, but few have measured CRP as a direct outcome.

What dose of NMN should I take for inflammation?

Human clinical trials have used doses ranging from 250 mg to 2,000 mg per day, with the most commonly studied effective range being 300 mg to 900 mg daily. Blood NAD+ increases appear dose-dependent up to around 600 mg per day in some trials. There is no established anti-inflammatory dose of NMN in humans. As with any supplement, discussing the appropriate dose and duration with a healthcare provider is advisable, especially for people with underlying health conditions.

Is NMN safe?

Based on clinical trials published to date, oral NMN appears safe and well tolerated at doses up to at least 1,250 mg per day in healthy adults for periods of up to several weeks. Multiple randomized controlled trials have reported no serious adverse events. Longer-term safety data are still accumulating, and there are theoretical questions about NMN in people with a history of certain cancers given NAD+'s role in DNA repair and cell proliferation. Anyone with cancer history or serious chronic conditions should discuss NMN with their healthcare provider before starting it.