Nicotinamide Mononucleotide (NMN)

Nicotinamide Mononucleotide (NMN and β-NMN) is a compound found naturally in the cells of our bodies and is integral to several cellular processes. NMN is a direct precursor to NAD+, a vital coenzyme essential for a myriad of cellular functions. The levels of NAD+ are known to decline as we age, and this decline is associated with aging and various age-related diseases. The has been shown in several clinical trials that by supplementing with NMN, we can boost the levels of NAD+ in the body, potentially counteracting age-related cellular decline and improving overall health. Preliminary studies, mainly in mice, suggest that NMN supplementation could offer a range of health benefits, such as enhanced energy metabolism and improved DNA repair, indicating its potential role in slowing the aging processes.

However, while NMN shows significant promise, comprehensive studies determining its long-term safety, effective dosage, and potential side effects in humans are still in progress. NMN is also present in several food sources, including broccoli, cabbage, cucumber, avocados, and edamame, but only in small quantities.

NMN and its impact on longevity are at the cutting edge of anti-aging research, with new discoveries and insights emerging regularly, deepening our understanding of the aging process and potential interventions to extend health and lifespan.

Sources of NMN in Food

NMN is naturally present in a variety of foods, albeit in relatively small quantities. Here is a list of some foods known to contain NMN, along with their respective NMN content. ^[1]


Food Type	Name	NMN Content (mg/100g-Food)
Vegetable	Edamame	0.47–1.88
Vegetable	Broccoli	0.25–1.12
Vegetable	Cucumber Seed	0.56
Vegetable	Cucumber Peel	0.65
Vegetable	Cabbage	0.0–0.90
Fruit	Avocado	0.36–1.60
Fruit	Tomato	0.26–0.30
Other	Mushroom	0.0–1.01
Meat	Beef (raw)	0.06–0.42
Seafood	Shrimp	0.22

While these foods can contribute to NAD+ levels through the provision of NMN, the quantities present are relatively small, and it is currently unclear whether dietary intake alone can significantly impact NAD+ levels in the body. Therefore, research into NMN supplementation is ongoing to explore its potential in maintaining or elevating NAD+ levels and mitigating age-related decline.

Legal

European Union (EU)

In the European Union, the classification and regulation of substances are often determined by their intended use and the claims made by the manufacturer or distributor. As of the latest update, Nicotinamide Mononucleotide (NMN) is classified as a chemical in the EU and has not been approved for human consumption. This classification is due to the EU's stringent regulations surrounding novel foods and substances, emphasizing consumer safety.

While NMN is not approved for human consumption in the EU, consumers may come across NMN products online that appear to be marketed for human use. However, these are officially sold either as chemicals for research and laboratory purposes or as supplements for animals, including dogs and cats. It is important for consumers to recognize the legal status and potential risks of such unapproved substances.

United States (US)

In November 2022, the US Food and Drug Administration (FDA) issued a statement saying that NMN may not be sold as a supplement, citing its status as being under investigation as a drug. This development is a reversal of the FDA's previous decision to allow its sale as a new dietary supplement (NDI). The reason for the reversal is unknown, but in December 2021, Metro International Biotech, a startup pharmaceutical company that has developed the NMN formulation MIB-626, wrote to the FDA: "As a company that has instituted publicly available clinical trials on ß-NMN, we request that FDA take the preclusion provision … seriously to protect the rights of companies that have spent significant time and research to develop drug products from competition from dietary supplements". According to Insider, the FDA confirmed that it had considered Metro's request. ^[2]

Different Forms of NMN

Nicotinamide Mononucleotide (NMN) exists in two stereoisomeric forms, α-NMN and β-NMN, which have the same molecular formula but differ in the spatial arrangement of atoms.

β-NMN

β-NMN is the biologically active form of NMN, predominantly utilized in scientific studies and supplements. It is integral in the biosynthesis of Nicotinamide Adenine Dinucleotide (NAD+), a vital coenzyme involved in numerous cellular processes, including energy metabolism, DNA repair, and cellular aging. When references are made to NMN in the context of supplementation or scientific research, it typically pertains to β-NMN due to its biological significance and activity.

α-NMN

α-NMN, on the other hand, does not participate in NAD+ biosynthesis and lacks the biological activity and associated health benefits of β-NMN. It is not the focus of NMN-related research or supplementation.

MIB-626

MIB-626, developed by MetroBiotech, is a microcrystalline form of NMN. This formulation may offer enhanced stability, solubility, or bioavailability compared to the regular crystalline form of NMN, potentially optimizing the efficacy of NMN supplementation.

Reduced NMN (NMNH)

Reduced Nicotinamide Mononucleotide (NMNH) is a potentially more effective NAD+ precursor.

Potential Benefits

NMN supplementation has been associated with several potential benefits, primarily due to its role as a precursor to NAD+, a crucial coenzyme involved in various cellular processes. Here are some potential benefits based on preliminary research:

Cellular Energy and Metabolism: By increasing NAD+ levels, NMN supplementation can potentially enhance cellular energy production and metabolism, leading to improved physiological functions and reduced age-related metabolic decline.
Longevity and Aging: Preliminary studies, particularly in animal models, have suggested that NMN can potentially extend lifespan and slow the aging process by improving cellular health and function, although more research is needed to confirm these effects in humans.
Cognitive Function: Some research indicates that NMN may have neuroprotective effects, potentially improving cognitive function and reducing the risk of neurodegenerative diseases by maintaining neuronal health and resilience.
Cardiovascular Health: NMN supplementation may offer cardiovascular benefits by improving blood flow and reducing the risk of age-related cardiovascular diseases, contributing to heart health and longevity.
DNA Repair: Enhanced NAD+ levels through NMN supplementation can support DNA repair mechanisms, potentially reducing DNA damage and the risk of mutation, which are associated with aging and cancer.
Insulin Sensitivity: NMN has been shown to improve insulin sensitivity, potentially reducing the risk of type 2 diabetes and metabolic syndrome, contributing to overall metabolic health.

Considerations for NMN Supplementation

When considering NMN supplementation, it is crucial to understand the potential interactions and impacts of NMN. Here are some considerations based on current knowledge and research.

Dosage and Effects

Human studies have indicated that a dosage of 1000 mg over 10 days can raise NAD levels about two-fold, and dosages as high as 2000 mg can triple the amount. However, the long-term safety, efficacy, and optimal dosage of NMN are still under investigation, and more comprehensive studies are needed to establish concrete guidelines for NMN supplementation. ^{[Citation needed]}

David Sinclair takes 1000 mg/day NMN in the morning.

Types of NMN Administration

Nicotinamide Mononucleotide (NMN) can be administered in various forms, each with its unique considerations. Below is a breakdown of the common types of NMN administration:

Oral Powder (Dissolved in Water): NMN powder can be dissolved in water and consumed as a drink. The benefit of this method, compared to capsules, is that the dosage can be easily adjusted, for example, reduced if side effects appear. In animal studies, particularly with mice, NMN is often mixed into the animals' drinking water.
Oral Powder (Mixed with Food): NMN powder can also be mixed with food items such as yogurt. This method is considered oral ingestion, similar to dissolving it in water, and subjects the NMN to the digestive process. Mixing NMN with food can be convenient for those who prefer not to take it sublingually or in capsule form and may help mask any unpleasant taste of the NMN powder when dissolved in water. However, the effectiveness and bioavailability of NMN when mixed with food have not been extensively studied, and the presence of other food components and the acidic environment might potentially influence the stability and absorption of NMN.
Capsule Form: NMN is encapsulated for easy consumption, offering a convenient and taste-neutral method. Like oral powder, capsules subject NMN to the digestive process. Capsule form is often used in clinical trials as it allows for precise dosing and is generally well-accepted by participants. It also enables the blinding of participants in placebo-controlled trials, maintaining the integrity of the study, as it is easier to make placebo capsules or tablets that are indistinguishable from the active ones.
Sublingual Powder: This form of NMN is taken by placing the powder directly under the tongue, allowing it to dissolve and be absorbed through the mucous membranes in the mouth. The general guideline is to hold the substance under the tongue for approximately 1 to 5 minutes to allow for adequate absorption through the sublingual gland. Some individuals believe sublingual administration offers better bioavailability due to direct absorption into the bloodstream, bypassing the digestive system. However, while this method is promoted in many YouTube videos, there is no evidence of any positive or negative effects and there is currently no clinical study utilizing sublingual administration. Furthermore, this method is relatively inconvenient, especially for those who might find the taste of sublingual powder too strong.

Optimal Timing for Supplementation

Our body has a natural rhythm where NAD+ levels fluctuate throughout the day rather than remaining constant, closely tied to our circadian rhythms.^[3] NAD+ plays a crucial role in regulating our body's internal clock. The Sirt-1 gene, which is influenced by NAD+, signals our body when it's time to eat or sleep.^[4]

Dr. David Sinclair suggests to take NMN in the morning when the natural rise in NAD+ and Sirt-1 activity should happen. Taking NMN e.g. at night might disrupt the NAD+ cycle and potentially affecting the sleep or hunger. This can be especially beneficial for frequent travelers trying to adjust to a new time zone, as a morning dose of NMN can help reset the body's internal clock and reduce jet lag. ^[5]

A recent RCT clinial trial investigated the effects of the time-dependent intake of NMN (250 mg/day) on older adults (≥ 65 years) over 12 weeks. Aging-induced insufficient physical activity and deterioration of physical function result in fatigue. This symptom frequently occurs among the elderly and has been complained by 27–50% of community-dwelling older adults in their daily life. Overall, NMN intake in the afternoon (in contrast to the morning) effectively improved lower limb function and reduced drowsiness in older adults. These findings suggest the potential of NMN in preventing loss of physical performance and improving fatigue in older adults.^[6]

Combining NMN with Methyl Donors

There is a theoretical concern that consuming NMN could deplete methyl groups in the body. This is because NMN is converted to NAD+ in the body, which can then be broken down into nicotinamide. Nicotinamide is then methylated by the liver to form N1-methylnicotinamide, which is excreted in the urine. This methylation process consumes a methyl group from S-adenosylmethionine (SAMe), the primary methyl donor in the body.

There could be a compensatory mechanisms that if methyl groups were being depleted at a concerning rate, the body would likely slow down the conversion of NMN to NAD+ or the methylation of nicotinamide. If not, there is a potential concern that excessive NMN supplementation might lead to a Methyl Donor Deficiency associated with low energy and tiredness, among other things.

For that reason, some individuals who take NMN also supplement with methyl donors like Trimethylglycine (TMG) to ensure that they are not depleting their body's methyl groups. While some individuals are taking methyl donors as a precautionary measure, others add them to their daily regime after feeling sleepiness by NMN.^[7]

However, there is no clear evidence yet as clinical trails are missing. While the pathway is known, the actual significance of NMN supplementation on global methyl group status is not well-established in humans. It would require substantial NMN consumption to have a significant impact coupled with insufficient intake of dietary methyl donors to replenish these groups.

Risks of NMN Supplementation

While NMN supplementation holds promise due to its potential anti-aging benefits and ability to enhance cellular metabolism, it is crucial to be aware of the potential risks involved. Here are some risks and considerations based on current knowledge and research:

Limited Human Studies: Most of the studies on NMN have been conducted in animal models, and there is limited data on its effects in humans. Therefore, the safety and efficacy of NMN supplementation in humans are not fully understood, and caution is advised until more research is conducted.
Potential Interaction with Medications: The interaction of NMN with various medications is not well studied, and there could be potential risks when combined with certain drugs. Individuals on medication should consult with a healthcare professional before considering NMN supplementation.
Theoretical Concerns: There are theoretical concerns regarding NMN’s potential to deplete methyl groups in the body, which could impact various biological processes, including DNA methylation and neurotransmitter synthesis. While this is a theoretical concern and not substantiated by concrete evidence, it is important to consider when evaluating the potential risks of NMN supplementation.^{[Citation needed]}
Over-Supplementation Risks: Excessive supplementation of NMN may lead to unknown side effects due to the lack of long-term human studies. Over-supplementation might also disrupt the natural balance of NAD+ and its related compounds in the body, potentially leading to unforeseen consequences.
Purity and Quality Concerns: The purity and quality of NMN supplements can vary, and impurities or contaminants in the supplements pose additional risks. It is essential to choose high-quality, reputable brands and sources for NMN supplements to minimize risks associated with impurities and contaminants.

Clinical Trials


Study	Design	Participants	Outcome
2020, Effect of oral administration of nicotinamide mononucleotide on clinical parameters and nicotinamide metabolite levels in healthy Japanese men ^[8]	singe admission of up to 500 mg oral admission at 9 AM	10 healthy men 40-60 years	admission was safe and well-tolerated
2021, Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women ^[1]	RCT, 10 weeks placebo (n=12) 250 mg/day (n=13)	25 postmenopausal women with prediabetes overweight or obese (BMI 25.3 - 39.1) 56 - 66 years	increase in skeletal muscle insulin signaling, insulin sensitivity, and muscle remodeling improvement in muscle insulin sensitivity is clinically relevant and is similar to the improvement observed after ~10% weight loss
2021, Nicotinamide mononucleotide supplementation enhances aerobic capacity in amateur runners: a randomized, double-blind study ^[9]	RCT, 6 weeks placebo (n=12) 300 mg/day (n=12) 600 mg/day (n=12) 1200 mg/day (n=12)	48 young and middle-aged recreationally trained runners 35 years in average	The combination of NMN supplementation and exercise further improves ventilatory threshold even among healthy young and middle-aged people. The improvement of aerobic capacity is in a dosage-dependent, large dosage of NMN with exercise has better effects. The improvement is muscle, not cardiac, related.
2022, Safety evaluation of β-nicotinamide mononucleotide oral administration in healthy adult men and women ^[10]	RCT, 4 weeks placebo (n=15) 1250 mg/day (n=16)	31 healthy adult men and women 20–65 years	Oral administration of 1250 mg of NMN, when administered once daily for up to 4 weeks, was safe and well-tolerated in healthy adult men and women. Oral administration of NMN in humans has a low adverse effect on renal function. Results indicate that NMN can be administered orally to humans at doses 1250 mg once daily for up to 4 weeks without causing hepatotoxicity and vasodilative flushing, and is believed to have a higher upper tolerable limit compared to NAM and NA.
2023, The efficacy and safety of β-nicotinamide mononucleotide (NMN) supplementation in healthy middle-aged adults: a randomized, multicenter, double-blind, placebo-controlled, parallel-group, dose-dependent clinical trial ^[11]	RCT, 8.5 weeks (60 days) placebo (n=20) 300 mg (n=20) 600 mg (n=20) 900 mg (n=20)	healthy males and females 40-65 (49.3 in average) years BMI between 18.5 and 35	Oral administration of NMN up to 900 mg/day for 60 days was safe and well tolerated blood NAD concentration was significantly and dose-dependently increased significant improvement of six-minute walking test, blood biological age, and SF-36 scores 900 mg/day oral dose did not give significantly better efficacy than 600 mg/day dose
2022, Effect of 12-Week Intake of Nicotinamide Mononucleotide on Sleep Quality, Fatigue, and Physical Performance in Older Japanese Adults: A Randomized, Double-Blind Placebo-Controlled Study ^[6]	RCT, 12 weeks placebo, before 12 pm placebo, after 6 pm 250 mg, before 12 pm 250 mg, after 6 pm	108 older adults ≥65 years	NMN intake in the afternoon is more effective in improving lower limb function and reducing drowsiness in older adults.

Todo

2023, The Safety and Antiaging Effects of Nicotinamide Mononucleotide in Human Clinical Trials: an Update ^[12]
2023, NAD⁺ exhaustion by CD38 upregulation contributes to blood pressure elevation and vascular damage in hypertension ^[13], https://www.nmn.com/news/nmn-lowers-blood-pressure-in-patients-with-hypertension-latest-human-trial
2014, SIRT2 induces the checkpoint kinase BubR1 to increase lifespan ^[14]
2023, Potential Synergistic Supplementation of NAD+ Promoting Compounds as a Strategy for Increasing Healthspan ^[15]
2020, NAD⁺ Repletion Rescues Female Fertility during Reproductive Aging ^[16]
https://www.nmn.com/news/nmn-tablet-blood-nad-levels-humans
https://link.springer.com/article/10.1007/s13668-023-00475-y
https://www.lifespan.io/topic/nmn-nicotinamide-mononucleotide-benefits-side-effects/
https://novoslabs.com/frequently-asked-questions/nmn-nicotinamide-mononucleotide/can-you-take-nmn-if-you-have-a-mthfr-mutation-or-suffer-from-reduced-methylation/

References

↑ ^1.0 ^1.1 Yoshino M et al.: Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women. Science 2021. (PMID 33888596) [PubMed] [DOI] [Full text] In rodents, obesity and aging impair nicotinamide adenine dinucleotide (NAD+) biosynthesis, which contributes to metabolic dysfunction. Nicotinamide mononucleotide (NMN) availability is a rate-limiting factor in mammalian NAD+ biosynthesis. We conducted a 10-week, randomized, placebo-controlled, double-blind trial to evaluate the effect of NMN supplementation on metabolic function in postmenopausal women with prediabetes who were overweight or obese. Insulin-stimulated glucose disposal, assessed by using the hyperinsulinemic-euglycemic clamp, and skeletal muscle insulin signaling [phosphorylation of protein kinase AKT and mechanistic target of rapamycin (mTOR)] increased after NMN supplementation but did not change after placebo treatment. NMN supplementation up-regulated the expression of platelet-derived growth factor receptor β and other genes related to muscle remodeling. These results demonstrate that NMN increases muscle insulin sensitivity, insulin signaling, and remodeling in women with prediabetes who are overweight or obese (clinicaltrial.gov NCT03151239).
↑ https://www.nmn.com/news/fda-bans-labeling-nmn-as-a-supplement
↑ Peek CB et al.: Circadian clock NAD+ cycle drives mitochondrial oxidative metabolism in mice. Science 2013. (PMID 24051248) [PubMed] [DOI] [Full text] Circadian clocks are self-sustained cellular oscillators that synchronize oxidative and reductive cycles in anticipation of the solar cycle. We found that the clock transcription feedback loop produces cycles of nicotinamide adenine dinucleotide (NAD(+)) biosynthesis, adenosine triphosphate production, and mitochondrial respiration through modulation of mitochondrial protein acetylation to synchronize oxidative metabolic pathways with the 24-hour fasting and feeding cycle. Circadian control of the activity of the NAD(+)-dependent deacetylase sirtuin 3 (SIRT3) generated rhythms in the acetylation and activity of oxidative enzymes and respiration in isolated mitochondria, and NAD(+) supplementation restored protein deacetylation and enhanced oxygen consumption in circadian mutant mice. Thus, circadian control of NAD(+) bioavailability modulates mitochondrial oxidative function and organismal metabolism across the daily cycles of fasting and feeding.
↑ Levine DC et al.: NAD⁺ Controls Circadian Reprogramming through PER2 Nuclear Translocation to Counter Aging. Mol Cell 2020. (PMID 32369735) [PubMed] [DOI] [Full text] Disrupted sleep-wake and molecular circadian rhythms are a feature of aging associated with metabolic disease and reduced levels of NAD+, yet whether changes in nucleotide metabolism control circadian behavioral and genomic rhythms remains unknown. Here, we reveal that supplementation with the NAD+ precursor nicotinamide riboside (NR) markedly reprograms metabolic and stress-response pathways that decline with aging through inhibition of the clock repressor PER2. NR enhances BMAL1 chromatin binding genome-wide through PER2K680 deacetylation, which in turn primes PER2 phosphorylation within a domain that controls nuclear transport and stability and that is mutated in human advanced sleep phase syndrome. In old mice, dampened BMAL1 chromatin binding, transcriptional oscillations, mitochondrial respiration rhythms, and late evening activity are restored by NAD+ repletion to youthful levels with NR. These results reveal effects of NAD+ on metabolism and the circadian system with aging through the spatiotemporal control of the molecular clock.
↑ 2021-12-27 - Interview Dr. David Sinclair - Huberman Lab Podcast - The Biology of Slowing & Reversing Aging
↑ ^6.0 ^6.1 Kim M et al.: Effect of 12-Week Intake of Nicotinamide Mononucleotide on Sleep Quality, Fatigue, and Physical Performance in Older Japanese Adults: A Randomized, Double-Blind Placebo-Controlled Study. Nutrients 2022. (PMID 35215405) [PubMed] [DOI] [Full text] Deteriorating sleep quality and physical or mental fatigue in older adults leads to decreased quality of life and increased mortality rates. This study investigated the effects of the time-dependent intake of nicotinamide mononucleotide (NMN) on sleep quality, fatigue, and physical performance in older adults. This randomized, double-blind placebo-controlled study evaluated 108 participants divided into four groups (NMN_AM; antemeridian, NMN_PM; post meridian, Placebo_AM, Placebo_PM). NMN (250 mg) or placebo was administered once a day for 12 weeks. Sleep quality was evaluated using the Pittsburgh Sleep Quality Index. Fatigue was evaluated using the "Jikaku-sho shirabe" questionnaire. Grip strength, 5-times sit-to-stand (5-STS), timed up and go, and 5-m habitual walk were evaluated to assess the physical performance. Significant interactions were observed between 5-STS and drowsiness. 5-STS of all groups on post-intervention and drowsiness of the NMN_PM and Placebo_PM groups on mid- and post-intervention showed significant improvement compared with those in pre-intervention. The NMN_PM group demonstrated the largest effect size for 5-STS (d = 0.72) and drowsiness (d = 0.64). Overall, NMN intake in the afternoon effectively improved lower limb function and reduced drowsiness in older adults. These findings suggest the potential of NMN in preventing loss of physical performance and improving fatigue in older adults.
↑ https://renuebyscience.com/forums/viewtopic.php?t=2575
↑ Irie J et al.: Effect of oral administration of nicotinamide mononucleotide on clinical parameters and nicotinamide metabolite levels in healthy Japanese men. Endocr J 2020. (PMID 31685720) [PubMed] [DOI] Recent studies have revealed that decline in cellular nicotinamide adenine dinucleotide (NAD+) levels causes aging-related disorders and therapeutic approaches increasing cellular NAD+ prevent these disorders in animal models. The administration of nicotinamide mononucleotide (NMN) has been shown to mitigate aging-related dysfunctions. However, the safety of NMN in humans have remained unclear. We, therefore, conducted a clinical trial to investigate the safety of single NMN administration in 10 healthy men. A single-arm non-randomized intervention was conducted by single oral administration of 100, 250, and 500 mg NMN. Clinical findings and parameters, and the pharmacokinetics of NMN metabolites were investigated for 5 h after each intervention. Ophthalmic examination and sleep quality assessment were also conducted before and after the intervention. The single oral administrations of NMN did not cause any significant clinical symptoms or changes in heart rate, blood pressure, oxygen saturation, and body temperature. Laboratory analysis results did not show significant changes, except for increases in serum bilirubin levels and decreases in serum creatinine, chloride, and blood glucose levels within the normal ranges, independent of the dose of NMN. Results of ophthalmic examination and sleep quality score showed no differences before and after the intervention. Plasma concentrations of N-methyl-2-pyridone-5-carboxamide and N-methyl-4-pyridone-5-carboxamide were significantly increased dose-dependently by NMN administration. The single oral administration of NMN was safe and effectively metabolized in healthy men without causing any significant deleterious effects. Thus, the oral administration of NMN was found to be feasible, implicating a potential therapeutic strategy to mitigate aging-related disorders in humans.
↑ Liao B et al.: Nicotinamide mononucleotide supplementation enhances aerobic capacity in amateur runners: a randomized, double-blind study. J Int Soc Sports Nutr 2021. (PMID 34238308) [PubMed] [DOI] [Full text] BACKGROUND: Recent studies in rodents indicate that a combination of exercise training and supplementation with nicotinamide adenine dinucleotide (NAD+) precursors has synergistic effects. However, there are currently no human clinical trials analyzing this. OBJECTIVE: This study investigates the effects of a combination of exercise training and supplementation with nicotinamide mononucleotide (NMN), the immediate precursor of NAD+, on cardiovascular fitness in healthy amateur runners. METHODS: A six-week randomized, double-blind, placebo-controlled, four-arm clinical trial including 48 young and middle-aged recreationally trained runners of the Guangzhou Pearl River running team was conducted. The participants were randomized into four groups: the low dosage group (300 mg/day NMN), the medium dosage group (600 mg/day NMN), the high dosage group (1200 mg/day NMN), and the control group (placebo). Each group consisted of ten male participants and two female participants. Each training session was 40-60 min, and the runners trained 5-6 times each week. Cardiopulmonary exercise testing was performed at baseline and after the intervention, at 6 weeks, to assess the aerobic capacity of the runners. RESULTS: Analysis of covariance of the change from baseline over the 6 week treatment showed that the oxygen uptake (VO2), percentages of maximum oxygen uptake (VO2max), power at first ventilatory threshold, and power at second ventilatory threshold increased to a higher degree in the medium and high dosage groups compared with the control group. However, there was no difference in VO2max, O2-pulse, VO2 related to work rate, and peak power after the 6 week treatment from baseline in any of these groups. CONCLUSION: NMN increases the aerobic capacity of humans during exercise training, and the improvement is likely the result of enhanced O2 utilization of the skeletal muscle. TRIAL REGISTRATION NUMBER: ChiCTR2000035138 .
↑ Fukamizu Y et al.: Safety evaluation of β-nicotinamide mononucleotide oral administration in healthy adult men and women. Sci Rep 2022. (PMID 36002548) [PubMed] [DOI] [Full text] A decrease in the intracellular level of nicotinamide adenine dinucleotide (NAD+), an essential coenzyme for metabolic activity, causes various age-related diseases and metabolic abnormalities. Both in-vivo and in-vitro studies have shown that increasing certain NAD+ levels in cell or tissue by supplementing nicotinamide mononucleotide (NMN), a precursor of NAD+, alleviates age-related diseases and metabolic disorders. In recent years, several clinical trials have been performed to elucidate NMN efficacy in humans. However, previous clinical studies with NMN have not reported on the safety of repeated daily oral administration of ≥ 1000 mg/shot in healthy adult men and women, and human clinical trials on NMN safety are limited. Therefore, we conducted a randomized, double-blind, placebo-controlled, parallel-group study to evaluate the safety of 1250 mg of β-NMN administered orally once daily for up to 4 weeks in 31 healthy adult men and women aged 20-65 years. Oral administration of β-NMN did not result in changes exceeding physiological variations in multiple clinical trials, including anthropometry, hematological, biochemical, urine, and body composition analyses. Moreover, no severe adverse events were observed during the study period. Our results indicate that β-NMN is safe and well-tolerated in healthy adult men and women an oral dose of 1250 mg once daily for up to 4 weeks.Trial registration Clinicaltrials.gov Identifier: UMIN000043084. Registered 21/01/2021. https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000049188 .
↑ Yi L et al.: The efficacy and safety of β-nicotinamide mononucleotide (NMN) supplementation in healthy middle-aged adults: a randomized, multicenter, double-blind, placebo-controlled, parallel-group, dose-dependent clinical trial. Geroscience 2023. (PMID 36482258) [PubMed] [DOI] [Full text] In animal studies, β-nicotinamide mononucleotide (NMN) supplementation increases nicotinamide adenine dinucleotide (NAD) concentrations and improves healthspan and lifespan with great safety. However, it is unclear if these effects can be transferred to humans. This randomized, multicenter, double-blind, placebo-controlled, parallel-group, dose-dependent clinical trial included 80 middle-aged healthy adults being randomized for a 60-day clinical trial with once daily oral dosing of placebo, 300 mg, 600 mg, or 900 mg NMN. The primary objective was to evaluate blood NAD concentration with dose-dependent regimens. The secondary objectives were to assess the safety and tolerability of NMN supplementation, next to the evaluation of clinical efficacy by measuring physical performance (six-minute walking test), blood biological age (Aging.Ai 3.0 calculator), Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), and subjective general health assessment [36-Item Short Form Survey Instrument (SF-36)]. Statistical analysis was performed using the Per Protocol analysis with significant level set at p = 0.05. All 80 participants completed the trial without trial protocol violation. Blood NAD concentrations were statistically significantly increased among all NMN-treated groups at day 30 and day 60 when compared to both placebo and baseline (all p ≤ 0.001). Blood NAD concentrations were highest in the groups taking 600 mg and 900 mg NMN. No safety issues, based on monitoring adverse events (AEs), laboratory and clinical measures, were found, and NMN supplementation was well tolerated. Walking distance increase during the six-minute walking test was statistically significantly higher in the 300 mg, 600 mg, and 900 mg groups compared to placebo at both days 30 and 60 (all p < 0.01), with longest walking distances measured in the 600 mg and 900 mg groups. The blood biological age increased significantly in the placebo group and stayed unchanged in all NMN-treated groups at day 60, which resulted in a significant difference between the treated groups and placebo (all p < 0.05). The HOMA-IR showed no statistically significant differences for all NMN-treated groups as compared to placebo at day 60. The change of SF-36 scores at day 30 and day 60 indicated statistically significantly better health of all three treated groups when compared to the placebo group (p < 0.05), except for the SF-36 score change in the 300 mg group at day 30. NMN supplementation increases blood NAD concentrations and is safe and well tolerated with oral dosing up to 900 mg NMN daily. Clinical efficacy expressed by blood NAD concentration and physical performance reaches highest at a dose of 600 mg daily oral intake. This trial was registered with ClinicalTrials.gov, NCT04823260, and Clinical Trial Registry - India, CTRI/2021/03/032421.
↑ Song Q et al.: The Safety and Antiaging Effects of Nicotinamide Mononucleotide in Human Clinical Trials: an Update. Adv Nutr 2023. (PMID 37619764) [PubMed] [DOI] The importance of nicotinamide adenine dinucleotide (NAD+) in human physiology is well recognized. As the NAD+ concentration in human skin, blood, liver, muscle, and brain are thought to decrease with age, finding ways to increase NAD+ status could possibly influence the aging process and associated metabolic sequelae. Nicotinamide mononucleotide (NMN) is a precursor for NAD+ biosynthesis, and in vitro/in vivo studies have demonstrated that NMN supplementation increases NAD+ concentration and could mitigate aging-related disorders such as oxidative stress, DNA damage, neurodegeneration, and inflammatory responses. The promotion of NMN as an antiaging health supplement has gained popularity due to such findings; however, since most studies evaluating the effects of NMN have been conducted in cell or animal models, a concern remains regarding the safety and physiological effects of NMN supplementation in the human population. Nonetheless, a dozen human clinical trials with NMN supplementation are currently underway. This review summarizes the current progress of these trials and NMN/NAD+ biology to clarify the potential effects of NMN supplementation and to shed light on future study directions.
↑ Qiu Y et al.: NAD⁺ exhaustion by CD38 upregulation contributes to blood pressure elevation and vascular damage in hypertension. Signal Transduct Target Ther 2023. (PMID 37718359) [PubMed] [DOI] [Full text] Hypertension is characterized by endothelial dysfunction and arterial stiffness, which contribute to the pathogenesis of atherosclerotic cardiovascular diseases. Nicotinamide adenine dinucleotide (NAD+) is an indispensable cofactor in all living cells that is involved in fundamental biological processes. However, in hypertensive patients, alterations in NAD+ levels and their relation with blood pressure (BP) elevation and vascular damage have not yet been studied. Here we reported that hypertensive patients exhibited lower NAD+ levels, as detected by high-performance liquid chromatography-mass spectrometry (HPLC-MS), in both peripheral blood mononuclear cells (PBMCs) and aortas, which was parallel to vascular dysfunction. NAD+ boosting therapy with nicotinamide mononucleotide (NMN) supplement reduced BP and ameliorated vascular dysfunction in hypertensive patients (NCT04903210) and AngII-induced hypertensive mice. Upregulation of CD38 in endothelial cells led to endothelial NAD+ exhaustion by reducing NMN bioavailability. Pro-inflammatory macrophages infiltration and increase in IL-1β generation derived from pro-inflammatory macrophages resulted in higher CD38 expression by activating JAK1-STAT1 signaling pathway. CD38 KO, CD38 inhibitors treatment, or adeno-associated virus (AAV)-mediated endothelial CD38 knockdown lowered BP and improved vascular dysfunction in AngII-induced hypertensive mice. The present study demonstrated for the first time that endothelial CD38 activation and subsequently accelerated NAD+ degradation due to enhanced macrophage-derived IL-1β production was responsible for BP elevation and vascular damage in hypertension. NAD+ boosting therapy can be used as a novel therapeutic strategy for the management of hypertensive patients.
↑ North BJ et al.: SIRT2 induces the checkpoint kinase BubR1 to increase lifespan. EMBO J 2014. (PMID 24825348) [PubMed] [DOI] [Full text] Mice overexpressing the mitotic checkpoint kinase gene BubR1 live longer, whereas mice hypomorphic for BubR1 (BubR1(H/H)) live shorter and show signs of accelerated aging. As wild-type mice age, BubR1 levels decline in many tissues, a process that is proposed to underlie normal aging and age-related diseases. Understanding why BubR1 declines with age and how to slow this process is therefore of considerable interest. The sirtuins (SIRT1-7) are a family of NAD(+)-dependent deacetylases that can delay age-related diseases. Here, we show that the loss of BubR1 levels with age is due to a decline in NAD(+) and the ability of SIRT2 to maintain lysine-668 of BubR1 in a deacetylated state, which is counteracted by the acetyltransferase CBP. Overexpression of SIRT2 or treatment of mice with the NAD(+) precursor nicotinamide mononucleotide (NMN) increases BubR1 abundance in vivo. Overexpression of SIRT2 in BubR1(H/H) animals increases median lifespan, with a greater effect in male mice. Together, these data indicate that further exploration of the potential of SIRT2 and NAD(+) to delay diseases of aging in mammals is warranted.
↑ Sharma A et al.: Potential Synergistic Supplementation of NAD+ Promoting Compounds as a Strategy for Increasing Healthspan. Nutrients 2023. (PMID 36678315) [PubMed] [DOI] [Full text] Disrupted biological function, manifesting through the hallmarks of aging, poses one of the largest threats to healthspan and risk of disease development, such as metabolic disorders, cardiovascular ailments, and neurodegeneration. In recent years, numerous geroprotectors, senolytics, and other nutraceuticals have emerged as potential disruptors of aging and may be viable interventions in the immediate state of human longevity science. In this review, we focus on the decrease in nicotinamide adenine dinucleotide (NAD+) with age and the supplementation of NAD+ precursors, such as nicotinamide mononucleotide (NMN) or nicotinamide riboside (NR), in combination with other geroprotective compounds, to restore NAD+ levels present in youth. Furthermore, these geroprotectors may enhance the efficacy of NMN supplementation while concurrently providing their own numerous health benefits. By analyzing the prevention of NAD+ degradation through the inhibition of CD38 or supporting protective downstream agents of SIRT1, we provide a potential framework of the CD38/NAD+/SIRT1 axis through which geroprotectors may enhance the efficacy of NAD+ precursor supplementation and reduce the risk of age-related diseases, thereby potentiating healthspan in humans.
↑ Bertoldo MJ et al.: NAD⁺ Repletion Rescues Female Fertility during Reproductive Aging. Cell Rep 2020. (PMID 32049001) [PubMed] [DOI] [Full text] Reproductive aging in female mammals is an irreversible process associated with declining oocyte quality, which is the rate-limiting factor to fertility. Here, we show that this loss of oocyte quality with age accompanies declining levels of the prominent metabolic cofactor nicotinamide adenine dinucleotide (NAD+). Treatment with the NAD+ metabolic precursor nicotinamide mononucleotide (NMN) rejuvenates oocyte quality in aged animals, leading to restoration in fertility, and this can be recapitulated by transgenic overexpression of the NAD+-dependent deacylase SIRT2, though deletion of this enzyme does not impair oocyte quality. These benefits of NMN extend to the developing embryo, where supplementation reverses the adverse effect of maternal age on developmental milestones. These findings suggest that late-life restoration of NAD+ levels represents an opportunity to rescue female reproductive function in mammals.

[pmid33888596-1] 1.0 ^1.1 Yoshino M et al.: Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women. Science 2021. (PMID 33888596) [PubMed] [DOI] [Full text] In rodents, obesity and aging impair nicotinamide adenine dinucleotide (NAD+) biosynthesis, which contributes to metabolic dysfunction. Nicotinamide mononucleotide (NMN) availability is a rate-limiting factor in mammalian NAD+ biosynthesis. We conducted a 10-week, randomized, placebo-controlled, double-blind trial to evaluate the effect of NMN supplementation on metabolic function in postmenopausal women with prediabetes who were overweight or obese. Insulin-stimulated glucose disposal, assessed by using the hyperinsulinemic-euglycemic clamp, and skeletal muscle insulin signaling [phosphorylation of protein kinase AKT and mechanistic target of rapamycin (mTOR)] increased after NMN supplementation but did not change after placebo treatment. NMN supplementation up-regulated the expression of platelet-derived growth factor receptor β and other genes related to muscle remodeling. These results demonstrate that NMN increases muscle insulin sensitivity, insulin signaling, and remodeling in women with prediabetes who are overweight or obese (clinicaltrial.gov NCT03151239).

[2] ttps://www.nmn.com/news/fda-bans-labeling-nmn-as-a-supplement

[pmid24051248-3] Peek CB et al.: Circadian clock NAD+ cycle drives mitochondrial oxidative metabolism in mice. Science 2013. (PMID 24051248) [PubMed] [DOI] [Full text] Circadian clocks are self-sustained cellular oscillators that synchronize oxidative and reductive cycles in anticipation of the solar cycle. We found that the clock transcription feedback loop produces cycles of nicotinamide adenine dinucleotide (NAD(+)) biosynthesis, adenosine triphosphate production, and mitochondrial respiration through modulation of mitochondrial protein acetylation to synchronize oxidative metabolic pathways with the 24-hour fasting and feeding cycle. Circadian control of the activity of the NAD(+)-dependent deacetylase sirtuin 3 (SIRT3) generated rhythms in the acetylation and activity of oxidative enzymes and respiration in isolated mitochondria, and NAD(+) supplementation restored protein deacetylation and enhanced oxygen consumption in circadian mutant mice. Thus, circadian control of NAD(+) bioavailability modulates mitochondrial oxidative function and organismal metabolism across the daily cycles of fasting and feeding.

[pmid32369735-4] Levine DC et al.: NAD⁺ Controls Circadian Reprogramming through PER2 Nuclear Translocation to Counter Aging. Mol Cell 2020. (PMID 32369735) [PubMed] [DOI] [Full text] Disrupted sleep-wake and molecular circadian rhythms are a feature of aging associated with metabolic disease and reduced levels of NAD+, yet whether changes in nucleotide metabolism control circadian behavioral and genomic rhythms remains unknown. Here, we reveal that supplementation with the NAD+ precursor nicotinamide riboside (NR) markedly reprograms metabolic and stress-response pathways that decline with aging through inhibition of the clock repressor PER2. NR enhances BMAL1 chromatin binding genome-wide through PER2K680 deacetylation, which in turn primes PER2 phosphorylation within a domain that controls nuclear transport and stability and that is mutated in human advanced sleep phase syndrome. In old mice, dampened BMAL1 chromatin binding, transcriptional oscillations, mitochondrial respiration rhythms, and late evening activity are restored by NAD+ repletion to youthful levels with NR. These results reveal effects of NAD+ on metabolism and the circadian system with aging through the spatiotemporal control of the molecular clock.

[5] 2021-12-27 - Interview Dr. David Sinclair - Huberman Lab Podcast - The Biology of Slowing & Reversing Aging

[pmid35215405-6] 6.0 ^6.1 Kim M et al.: Effect of 12-Week Intake of Nicotinamide Mononucleotide on Sleep Quality, Fatigue, and Physical Performance in Older Japanese Adults: A Randomized, Double-Blind Placebo-Controlled Study. Nutrients 2022. (PMID 35215405) [PubMed] [DOI] [Full text] Deteriorating sleep quality and physical or mental fatigue in older adults leads to decreased quality of life and increased mortality rates. This study investigated the effects of the time-dependent intake of nicotinamide mononucleotide (NMN) on sleep quality, fatigue, and physical performance in older adults. This randomized, double-blind placebo-controlled study evaluated 108 participants divided into four groups (NMN_AM; antemeridian, NMN_PM; post meridian, Placebo_AM, Placebo_PM). NMN (250 mg) or placebo was administered once a day for 12 weeks. Sleep quality was evaluated using the Pittsburgh Sleep Quality Index. Fatigue was evaluated using the "Jikaku-sho shirabe" questionnaire. Grip strength, 5-times sit-to-stand (5-STS), timed up and go, and 5-m habitual walk were evaluated to assess the physical performance. Significant interactions were observed between 5-STS and drowsiness. 5-STS of all groups on post-intervention and drowsiness of the NMN_PM and Placebo_PM groups on mid- and post-intervention showed significant improvement compared with those in pre-intervention. The NMN_PM group demonstrated the largest effect size for 5-STS (d = 0.72) and drowsiness (d = 0.64). Overall, NMN intake in the afternoon effectively improved lower limb function and reduced drowsiness in older adults. These findings suggest the potential of NMN in preventing loss of physical performance and improving fatigue in older adults.

[7] ttps://renuebyscience.com/forums/viewtopic.php?t=2575

[pmid31685720-8] Irie J et al.: Effect of oral administration of nicotinamide mononucleotide on clinical parameters and nicotinamide metabolite levels in healthy Japanese men. Endocr J 2020. (PMID 31685720) [PubMed] [DOI] Recent studies have revealed that decline in cellular nicotinamide adenine dinucleotide (NAD+) levels causes aging-related disorders and therapeutic approaches increasing cellular NAD+ prevent these disorders in animal models. The administration of nicotinamide mononucleotide (NMN) has been shown to mitigate aging-related dysfunctions. However, the safety of NMN in humans have remained unclear. We, therefore, conducted a clinical trial to investigate the safety of single NMN administration in 10 healthy men. A single-arm non-randomized intervention was conducted by single oral administration of 100, 250, and 500 mg NMN. Clinical findings and parameters, and the pharmacokinetics of NMN metabolites were investigated for 5 h after each intervention. Ophthalmic examination and sleep quality assessment were also conducted before and after the intervention. The single oral administrations of NMN did not cause any significant clinical symptoms or changes in heart rate, blood pressure, oxygen saturation, and body temperature. Laboratory analysis results did not show significant changes, except for increases in serum bilirubin levels and decreases in serum creatinine, chloride, and blood glucose levels within the normal ranges, independent of the dose of NMN. Results of ophthalmic examination and sleep quality score showed no differences before and after the intervention. Plasma concentrations of N-methyl-2-pyridone-5-carboxamide and N-methyl-4-pyridone-5-carboxamide were significantly increased dose-dependently by NMN administration. The single oral administration of NMN was safe and effectively metabolized in healthy men without causing any significant deleterious effects. Thus, the oral administration of NMN was found to be feasible, implicating a potential therapeutic strategy to mitigate aging-related disorders in humans.

[pmid34238308-9] Liao B et al.: Nicotinamide mononucleotide supplementation enhances aerobic capacity in amateur runners: a randomized, double-blind study. J Int Soc Sports Nutr 2021. (PMID 34238308) [PubMed] [DOI] [Full text] BACKGROUND: Recent studies in rodents indicate that a combination of exercise training and supplementation with nicotinamide adenine dinucleotide (NAD+) precursors has synergistic effects. However, there are currently no human clinical trials analyzing this. OBJECTIVE: This study investigates the effects of a combination of exercise training and supplementation with nicotinamide mononucleotide (NMN), the immediate precursor of NAD+, on cardiovascular fitness in healthy amateur runners. METHODS: A six-week randomized, double-blind, placebo-controlled, four-arm clinical trial including 48 young and middle-aged recreationally trained runners of the Guangzhou Pearl River running team was conducted. The participants were randomized into four groups: the low dosage group (300 mg/day NMN), the medium dosage group (600 mg/day NMN), the high dosage group (1200 mg/day NMN), and the control group (placebo). Each group consisted of ten male participants and two female participants. Each training session was 40-60 min, and the runners trained 5-6 times each week. Cardiopulmonary exercise testing was performed at baseline and after the intervention, at 6 weeks, to assess the aerobic capacity of the runners. RESULTS: Analysis of covariance of the change from baseline over the 6 week treatment showed that the oxygen uptake (VO2), percentages of maximum oxygen uptake (VO2max), power at first ventilatory threshold, and power at second ventilatory threshold increased to a higher degree in the medium and high dosage groups compared with the control group. However, there was no difference in VO2max, O2-pulse, VO2 related to work rate, and peak power after the 6 week treatment from baseline in any of these groups. CONCLUSION: NMN increases the aerobic capacity of humans during exercise training, and the improvement is likely the result of enhanced O2 utilization of the skeletal muscle. TRIAL REGISTRATION NUMBER: ChiCTR2000035138 .

[pmid36002548-10] Fukamizu Y et al.: Safety evaluation of β-nicotinamide mononucleotide oral administration in healthy adult men and women. Sci Rep 2022. (PMID 36002548) [PubMed] [DOI] [Full text] A decrease in the intracellular level of nicotinamide adenine dinucleotide (NAD+), an essential coenzyme for metabolic activity, causes various age-related diseases and metabolic abnormalities. Both in-vivo and in-vitro studies have shown that increasing certain NAD+ levels in cell or tissue by supplementing nicotinamide mononucleotide (NMN), a precursor of NAD+, alleviates age-related diseases and metabolic disorders. In recent years, several clinical trials have been performed to elucidate NMN efficacy in humans. However, previous clinical studies with NMN have not reported on the safety of repeated daily oral administration of ≥ 1000 mg/shot in healthy adult men and women, and human clinical trials on NMN safety are limited. Therefore, we conducted a randomized, double-blind, placebo-controlled, parallel-group study to evaluate the safety of 1250 mg of β-NMN administered orally once daily for up to 4 weeks in 31 healthy adult men and women aged 20-65 years. Oral administration of β-NMN did not result in changes exceeding physiological variations in multiple clinical trials, including anthropometry, hematological, biochemical, urine, and body composition analyses. Moreover, no severe adverse events were observed during the study period. Our results indicate that β-NMN is safe and well-tolerated in healthy adult men and women an oral dose of 1250 mg once daily for up to 4 weeks.Trial registration Clinicaltrials.gov Identifier: UMIN000043084. Registered 21/01/2021. https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000049188 .

[pmid36482258-11] Yi L et al.: The efficacy and safety of β-nicotinamide mononucleotide (NMN) supplementation in healthy middle-aged adults: a randomized, multicenter, double-blind, placebo-controlled, parallel-group, dose-dependent clinical trial. Geroscience 2023. (PMID 36482258) [PubMed] [DOI] [Full text] In animal studies, β-nicotinamide mononucleotide (NMN) supplementation increases nicotinamide adenine dinucleotide (NAD) concentrations and improves healthspan and lifespan with great safety. However, it is unclear if these effects can be transferred to humans. This randomized, multicenter, double-blind, placebo-controlled, parallel-group, dose-dependent clinical trial included 80 middle-aged healthy adults being randomized for a 60-day clinical trial with once daily oral dosing of placebo, 300 mg, 600 mg, or 900 mg NMN. The primary objective was to evaluate blood NAD concentration with dose-dependent regimens. The secondary objectives were to assess the safety and tolerability of NMN supplementation, next to the evaluation of clinical efficacy by measuring physical performance (six-minute walking test), blood biological age (Aging.Ai 3.0 calculator), Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), and subjective general health assessment [36-Item Short Form Survey Instrument (SF-36)]. Statistical analysis was performed using the Per Protocol analysis with significant level set at p = 0.05. All 80 participants completed the trial without trial protocol violation. Blood NAD concentrations were statistically significantly increased among all NMN-treated groups at day 30 and day 60 when compared to both placebo and baseline (all p ≤ 0.001). Blood NAD concentrations were highest in the groups taking 600 mg and 900 mg NMN. No safety issues, based on monitoring adverse events (AEs), laboratory and clinical measures, were found, and NMN supplementation was well tolerated. Walking distance increase during the six-minute walking test was statistically significantly higher in the 300 mg, 600 mg, and 900 mg groups compared to placebo at both days 30 and 60 (all p < 0.01), with longest walking distances measured in the 600 mg and 900 mg groups. The blood biological age increased significantly in the placebo group and stayed unchanged in all NMN-treated groups at day 60, which resulted in a significant difference between the treated groups and placebo (all p < 0.05). The HOMA-IR showed no statistically significant differences for all NMN-treated groups as compared to placebo at day 60. The change of SF-36 scores at day 30 and day 60 indicated statistically significantly better health of all three treated groups when compared to the placebo group (p < 0.05), except for the SF-36 score change in the 300 mg group at day 30. NMN supplementation increases blood NAD concentrations and is safe and well tolerated with oral dosing up to 900 mg NMN daily. Clinical efficacy expressed by blood NAD concentration and physical performance reaches highest at a dose of 600 mg daily oral intake. This trial was registered with ClinicalTrials.gov, NCT04823260, and Clinical Trial Registry - India, CTRI/2021/03/032421.

[pmid37619764-12] Song Q et al.: The Safety and Antiaging Effects of Nicotinamide Mononucleotide in Human Clinical Trials: an Update. Adv Nutr 2023. (PMID 37619764) [PubMed] [DOI] The importance of nicotinamide adenine dinucleotide (NAD+) in human physiology is well recognized. As the NAD+ concentration in human skin, blood, liver, muscle, and brain are thought to decrease with age, finding ways to increase NAD+ status could possibly influence the aging process and associated metabolic sequelae. Nicotinamide mononucleotide (NMN) is a precursor for NAD+ biosynthesis, and in vitro/in vivo studies have demonstrated that NMN supplementation increases NAD+ concentration and could mitigate aging-related disorders such as oxidative stress, DNA damage, neurodegeneration, and inflammatory responses. The promotion of NMN as an antiaging health supplement has gained popularity due to such findings; however, since most studies evaluating the effects of NMN have been conducted in cell or animal models, a concern remains regarding the safety and physiological effects of NMN supplementation in the human population. Nonetheless, a dozen human clinical trials with NMN supplementation are currently underway. This review summarizes the current progress of these trials and NMN/NAD+ biology to clarify the potential effects of NMN supplementation and to shed light on future study directions.

[pmid37718359-13] Qiu Y et al.: NAD⁺ exhaustion by CD38 upregulation contributes to blood pressure elevation and vascular damage in hypertension. Signal Transduct Target Ther 2023. (PMID 37718359) [PubMed] [DOI] [Full text] Hypertension is characterized by endothelial dysfunction and arterial stiffness, which contribute to the pathogenesis of atherosclerotic cardiovascular diseases. Nicotinamide adenine dinucleotide (NAD+) is an indispensable cofactor in all living cells that is involved in fundamental biological processes. However, in hypertensive patients, alterations in NAD+ levels and their relation with blood pressure (BP) elevation and vascular damage have not yet been studied. Here we reported that hypertensive patients exhibited lower NAD+ levels, as detected by high-performance liquid chromatography-mass spectrometry (HPLC-MS), in both peripheral blood mononuclear cells (PBMCs) and aortas, which was parallel to vascular dysfunction. NAD+ boosting therapy with nicotinamide mononucleotide (NMN) supplement reduced BP and ameliorated vascular dysfunction in hypertensive patients (NCT04903210) and AngII-induced hypertensive mice. Upregulation of CD38 in endothelial cells led to endothelial NAD+ exhaustion by reducing NMN bioavailability. Pro-inflammatory macrophages infiltration and increase in IL-1β generation derived from pro-inflammatory macrophages resulted in higher CD38 expression by activating JAK1-STAT1 signaling pathway. CD38 KO, CD38 inhibitors treatment, or adeno-associated virus (AAV)-mediated endothelial CD38 knockdown lowered BP and improved vascular dysfunction in AngII-induced hypertensive mice. The present study demonstrated for the first time that endothelial CD38 activation and subsequently accelerated NAD+ degradation due to enhanced macrophage-derived IL-1β production was responsible for BP elevation and vascular damage in hypertension. NAD+ boosting therapy can be used as a novel therapeutic strategy for the management of hypertensive patients.

[pmid24825348-14] North BJ et al.: SIRT2 induces the checkpoint kinase BubR1 to increase lifespan. EMBO J 2014. (PMID 24825348) [PubMed] [DOI] [Full text] Mice overexpressing the mitotic checkpoint kinase gene BubR1 live longer, whereas mice hypomorphic for BubR1 (BubR1(H/H)) live shorter and show signs of accelerated aging. As wild-type mice age, BubR1 levels decline in many tissues, a process that is proposed to underlie normal aging and age-related diseases. Understanding why BubR1 declines with age and how to slow this process is therefore of considerable interest. The sirtuins (SIRT1-7) are a family of NAD(+)-dependent deacetylases that can delay age-related diseases. Here, we show that the loss of BubR1 levels with age is due to a decline in NAD(+) and the ability of SIRT2 to maintain lysine-668 of BubR1 in a deacetylated state, which is counteracted by the acetyltransferase CBP. Overexpression of SIRT2 or treatment of mice with the NAD(+) precursor nicotinamide mononucleotide (NMN) increases BubR1 abundance in vivo. Overexpression of SIRT2 in BubR1(H/H) animals increases median lifespan, with a greater effect in male mice. Together, these data indicate that further exploration of the potential of SIRT2 and NAD(+) to delay diseases of aging in mammals is warranted.

[pmid36678315-15] Sharma A et al.: Potential Synergistic Supplementation of NAD+ Promoting Compounds as a Strategy for Increasing Healthspan. Nutrients 2023. (PMID 36678315) [PubMed] [DOI] [Full text] Disrupted biological function, manifesting through the hallmarks of aging, poses one of the largest threats to healthspan and risk of disease development, such as metabolic disorders, cardiovascular ailments, and neurodegeneration. In recent years, numerous geroprotectors, senolytics, and other nutraceuticals have emerged as potential disruptors of aging and may be viable interventions in the immediate state of human longevity science. In this review, we focus on the decrease in nicotinamide adenine dinucleotide (NAD+) with age and the supplementation of NAD+ precursors, such as nicotinamide mononucleotide (NMN) or nicotinamide riboside (NR), in combination with other geroprotective compounds, to restore NAD+ levels present in youth. Furthermore, these geroprotectors may enhance the efficacy of NMN supplementation while concurrently providing their own numerous health benefits. By analyzing the prevention of NAD+ degradation through the inhibition of CD38 or supporting protective downstream agents of SIRT1, we provide a potential framework of the CD38/NAD+/SIRT1 axis through which geroprotectors may enhance the efficacy of NAD+ precursor supplementation and reduce the risk of age-related diseases, thereby potentiating healthspan in humans.

[pmid32049001-16] Bertoldo MJ et al.: NAD⁺ Repletion Rescues Female Fertility during Reproductive Aging. Cell Rep 2020. (PMID 32049001) [PubMed] [DOI] [Full text] Reproductive aging in female mammals is an irreversible process associated with declining oocyte quality, which is the rate-limiting factor to fertility. Here, we show that this loss of oocyte quality with age accompanies declining levels of the prominent metabolic cofactor nicotinamide adenine dinucleotide (NAD+). Treatment with the NAD+ metabolic precursor nicotinamide mononucleotide (NMN) rejuvenates oocyte quality in aged animals, leading to restoration in fertility, and this can be recapitulated by transgenic overexpression of the NAD+-dependent deacylase SIRT2, though deletion of this enzyme does not impair oocyte quality. These benefits of NMN extend to the developing embryo, where supplementation reverses the adverse effect of maternal age on developmental milestones. These findings suggest that late-life restoration of NAD+ levels represents an opportunity to rescue female reproductive function in mammals.

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