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Human Trial of NMN Supplement Concludes

Human Data From a Nicotinamide Mononucleotide Human Trial


A human trial of the popular NMN supplement has recently concluded, and the results are not impressive at all. However, this is perfectly fine because that was not the purpose of the study, and, despite the lackluster results, the study was a success!

This might sound strange, but perhaps the words of the study authors may make it a bit clearer why this is absolutely no cause for alarm.

We, therefore, conducted a clinical trial to investigate the safety of single NMN administration in 10 healthy men.

The reason we should not be concerned with the results of this small human trial of the NMN supplement is because it achieved what it set out to establish: to demonstrate that the drug is safe and well tolerated at the dosage used.

NMN supplement put to the safety test

The trial did not set out to demonstrate efficacy of NMN, and given the small number of trial participants, the single dose, and the short study time, it was only to establish that the drug is safe. The study at the Clinical Trial Unit, Keio University School of Medicine, Japan included a total of 10 healthy men aged between 40 and 60 years old and observed them to ensure that there were no adverse side effects.

During the study, the researchers observed various biomarkers, and no significant changes were evident following the single dose of NMN. This is hardly surprising, as the dosage range used of 100, 250, and 500 mg is also fairly low. The only notable result was that bilirubin levels rose by 51.3% and glucose fell by 11.7% following dosage. However, those two changes are most likely associated with the overnight fast prior to taking NMN and the five-hour fast following dosage.

The researchers also could not detect NMN in the blood samples taken in the study, but this is likely due to them being frozen before extraction, which degraded the NMN. This is unfortunate, but it serves as a useful cautionary tale for future studies to hopefully learn from.


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.


There have been a plethora of mouse studies; however, the safety and efficacy of NMN in humans was unclear, and this trial helps to confirm that, in general, the drug is safe and well tolerated; to that end, the trial can be considered a success.

The next step for researchers will be to investigate the efficacy of NMN, and a suitable dosage and frequency would then be established as part of that process. Of course, it is certainly possible that NMN may fail during efficacy testing in humans, but this initial safety study has no bearing on that potential outcome whatsoever.

There is currently an ongoing human trial for NMN at Brigham and Women’s Hospital in Boston from which efficacy data should be forthcoming, and until that data is in, no conclusion beyond NMN being safe can really be drawn.

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Irie, J., Inagaki, E., Fujita, M., Nakaya, H., Mitsuishi, M., Yamaguchi, S., … & Okano, H. (2019). Effect of oral administration of nicotinamide mononucleotide on clinical parameters and nicotinamide metabolite levels in healthy Japanese men. Endocrine journal, EJ19-0313.

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About the author

Steve Hill

Steve serves on the LEAF Board of Directors and is the Editor in Chief, coordinating the daily news articles and social media content of the organization. He is an active journalist in the aging research and biotechnology field and has to date written over 600 articles on the topic, interviewed over 100 of the leading researchers in the field, hosted livestream events focused on aging, as well as attending various medical industry conferences. His work has been featured in H+ magazine, Psychology Today, Singularity Weblog, Standpoint Magazine, Swiss Monthly, Keep me Prime, and New Economy Magazine. Steve is one of three recipients of the 2020 H+ Innovator Award and shares this honour with Mirko Ranieri – Google AR and Dinorah Delfin – Immortalists Magazine. The H+ Innovator Award looks into our community and acknowledges ideas and projects that encourage social change, achieve scientific accomplishments, technological advances, philosophical and intellectual visions, author unique narratives, build fascinating artistic ventures, and develop products that bridge gaps and help us to achieve transhumanist goals. Steve has a background in project management and administration which has helped him to build a united team for effective fundraising and content creation, while his additional knowledge of biology and statistical data analysis allows him to carefully assess and coordinate the scientific groups involved in the project.
  1. rob
    February 18, 2020

    Is David Sinclair involved in this publication…or does he endorse it?
    Just finished his very interesting book “Lifespan”


  2. jewell_john_patrick
    June 9, 2020

    I use it.

    • gonerunninjacc
      August 31, 2020

      And at what dose.
      I’m a distance runner and aging …..

  3. sbstrum
    August 13, 2020

    This 10 patient study is an entree and in no way would I consider any med or supplement “safe” based on such a small study population. The increase in bilirubin should be discussed not only as a % change but with absolute levels. Perhaps the 51% increase relates to 0.1 going to 0.15. How many patients had abnormal biliirubin levels? Conclusions that “elevations” were seen needs to be confirmed with absolute values and although fasting does ↑ bilirubin, we should be more scientific in how we arrive at clinical speculations. At age 77, I am all for anything to improve longevity.
    Stephen B. Strum, MD, FACP

One Trackback

  1. September 15, 2020

    […] how does it affect humans? Human safety trials conducted in taking NMN show that the drug is safe and well-tolerated at the dosage […]

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