Is Your NMN Supplement Safe and Does Its Potency Last?

NMN supplement

The NR and NMN supplement are the two most tested NAD precursors. There’s so much demand for them that supplement companies have difficulty keeping them in stock. Of the two, NR has been the most studied in humans, but now a Japanese study has published its results that show that NMN is safe for human consumption. Also, pure NMN can retain its potency for up to six months without refrigeration.

NMN supplementOver the last few years, I’ve written several articles about two promising NAD precursors, the NR (Nicotinamide Riboside) and NMN supplement (Nicotinamide Mononucleotide). Among the many reasons you may want to know about them, these two stand out:

  1. NAD is a coenzyme found in nearly all our cells and is essential for life, but unfortunately it quickly declines in our body as we age. When NAD levels decline, what also happens is that a group of proteins called sirtuins — the so-called “longevity genes — become less able to do their job of regulating cellular health, and prolonging healthy aging. (1)
  2. Two molecules that are available as supplements, NR and NMN are precursors to NAD, meaning that they can boost NAD levels. This has been proven in numerous mouse studies and one human trial using the NR precursor. (2, 3) NMN has also been proven to boost NAD in mouse studies. Of the three NMN human studies I’m aware of, only one, the Japanese study, has been published, and it only looked at NMN safety, not its ability to, in effect, make people biologically younger, as it did with mice. The other two human trials testing NMN are being conducted by the Washington University School of Medicine (4) and at Brigham and Women’s Hospital near the Harvard Medical School facility. (5)

I return to this NAD precursor topic now because of widespread confusion over two things:

  • NMN supplement shelf life, and
  • NMN supplement safety.

Many people who consume NMN and follow the research on it were alarmed over a recent comment by one of the world’s most renown NMN researchers, Dr. David Sinclair, who in an interview with Dr. Rhonda Patrick indicated that NMN needs to be refrigerated. Since NMN is not delivered to consumers cold, nor are there instructions to keep it cold, this set off alarm bells. As I’ll detail in a moment, stop ringing those bells — there’s no emergency.

Regarding NMN safety for humans, that Japanese study mentioned above finally concluded after three years and showed that NMN is safe for humans at the doses studied. (More on that in a bit.)

Let’s examine NMN shelf life and safety more closely.


NMN Supplement Shelf Life

This is the transcript part of the one hour-plus interview between Dr. Sinclair and Dr. Patrick that concerns the shelf life of NMN:

David: … Actually, you remind me to say something important for the listeners. Make sure your NR and your NMN is kept in the cold. If it’s just on the shelf and it’s not in a stabilized form, then it will degrade into nicotinamide, which is something you don’t want to take high doses of because we’ve showed in my lab many years ago that nicotinamide will inhibit the sirtuins, and PARP as well, and interfere with DNA repair.

Rhonda: What? Really?

David: Yeah.

Rhonda: Like the form that’s in vitamins?

David: Right. It doesn’t have a super long shelf life, that’s not very well known. So keep it cool, in a freezer or the fridge.

Rhonda: But I mean, like, if you’re buying nicotinamide riboside, you know, from a variety of companies that make it, it’s certainly not shipped to you cold. So the question is how much of it’s already degraded just on the shelf?

David: I don’t know.

Rhonda: I mean, it’s kind of the case with probiotics. You know, when you get probiotics, you want them to be shipped to you cold, you know, so that they’re live.

David: Right. Same thing here. We have to also replace our mouse NMN. We put it in their water. We replace that every week because it goes off, but if it gets wet or it gets a bit of humidity in the bottle, it’s only a short time before it’s degrading.

Here’s the video already cued to Dr. Sinclair’s comment about NMN’s shelf life:


(If you’re interested in extending your healthy lifespan, I strongly recommend you watch the entire video!)

There are three reasons that NMN has no potency or shelf life issues:

(1) Certified Tests Show That Pure NMN Need Not Be Kept Cold

Dr. Sinclair knows more about NMN and the science of longevity than I ever will, but in the case of the NMN supplement I use from ProHealth (a company I advise), he’s not accurate about how NMN degrades if not kept cold. It could be that his perception on this was formed with the NMN supplies he has received in the past for his lab experiments. NMN production techniques have  improved immensely recently, resulting in a very stable product, assuming it was pure NMN to begin with.

The following document, NMN Stability Report, shows ProHealth’s NMN products remain nearly 100% pure up to three months in temperatures between 39.2° F (4°C) and 104°F (40°C). What’s not shown in this particular document is that subsequent tests showed over 98% NMN supplement purity at the six month mark as well.

A pure NMN supplement retains its potency for up to six months without refridgeration(2) It’s Natural That NMN Will Degrade In Water After One Week

Not only does high heat degrade the potency of supplements, so does water. Oxidation in water causes water-soluble vitamins and probiotics to degrade with time. Just as nails rust in damp air and apples turn brown when cut open, water soluble vitamins and probiotics degrade when exposed to water and oxygen.

It then makes sense, as Dr. Sinclair said, that the NMN in the water used to administer it to his lab mice had to be changed weekly. Water will degrade supplements over time. If the NMN supplement you buy is pure to begin with, keep it in the container it came in.

(3) ProHealth’s NMN Supplement Inventory Sells Out Quickly

Given the high demand for NMN, like many brands that offer pure NMN, ProHealth’s inventory sells out nearly as fast as it’s made, so it’s always fresh when received by our customers. If you buy it and don’t intend to use it in less than three months, store it in the freezer; otherwise, no special storage is necessary.

I hope I adequately addressed the NMN potency and shelf life question. Next up is to address the misconception about what the Japanese study did and didn’t confirm.


Is The NMN Supplement Safe For People?

Fast answer — Yes.

The story on NMN safety begins three years ago in Japan where the first human clinical study to evaluate NMN’s safety was announced. Everyone who studies and consumes the NMN supplement to boost NAD in their body was excited to finally learn if NMN supplementation conferred similar lifespan enhancing attributes to humans that many research studies showed that it did in mouse models.

I will examine the objectives of the Japanese NMN human trial and remark on the recently published results, which have been widely misunderstood. This study’s conclusion was not that NMN was ineffective at boosting NAD levels in the research participants, thereby did not confer health and longevity benefits to them. This potential was not examined. Instead, what the study did examine and show is that NMN is safe for humans. (6)

Why Do The Study?

In announcing the study, science and technology journal Nature made four noteworthy observations to underscore why the NMN human study would be conducted. (7)

(1) Of the various disease-mitigating life extension enhancing interventions, the most practical are NAD precursors. One big reason for this that the vast amount of data accumulated over the last 16 years indicate that NAD, a coenzyme found in virtually all our cells and essential for life, makes sirtuins work better. Sirtuins are a family of proteins that researchers say can promote longevity if they’re working effectively, which requires adequate levels of NAD to do. Unfortunately, NAD levels fall as we age.

(2) NAD itself is difficult to administer directly to humans, but its precursors — nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN) — are promising natural compounds with which to augment NAD levels in the cells and the body. The idea then is, take NMN or NR to boost NAD, which then makes the sirtuins do a better job of keeping you healthy and long-lived. (8)

(3) Both NR and NMN have been shown to be beneficial to ameliorate complications in glucose metabolism, cardiovascular and neural functions, and stem cell maintenance — and even promote longevity in some studies, mainly of mice. (9)

(4) For NR, several clinical studies have already been ongoing in the US and Europe, and one human trial showed that NR does boost people’s level of NAD. In the case of NMN, although it is already available on the market, the safety and effect on human physiology remain unknown.

Those observations were made in 2016 and were among the reasons cited to conduct the first NMN human trial in Japan. Those of us who follow longevity science waited with bated breath for the results. We would finally know if all those age-defying wonders conferred to mice by NMN would actually work for people as well.

What The Japanese NMN Human Study Did and Did Not Show

Those four points made above is the basic reason why the study of NMN on humans was conceived. About three years later on November 2, 2019 the results were released and reported on by Endocrine Journal; they were underwhelming, because NMN users expected more.

Unlike expectations, the study only evaluated whether NMN is safe for humans, not its effectiveness at boosting NAD to the extent necessary to have a favorable impact on sirtuins (the so-called “longevity genes”), and thus improve the health and longevity outcomes in people.

The study was done on only ten healthy men, ages 40 to 60. They were given a single oral administration of 100, 250, and 500 mgs of NMN. The men were then evaluated to see how those dosages of NMN affected various health parameters.

The researchers found that no single oral administration of NMN caused any significant clinical symptoms or changes in heart rate, blood pressure, oxygen saturation, and body temperature, but there are at least three notable points to consider about the NMN human study:

  1. All NMN doses were fairly low. Even the highest dose of 500 mgs is but half of what one of the preeminent NMN researchers, Dr. David Sinclair, and his family take. No animal studies showed the health and longevity benefits of NMN tested with just a single dose, but rather administered NMN daily for months.
  2. NMN is safe and well tolerated; to that end, the human trial can be considered a success.
  3. Researchers now need to investigate the efficacy of NMN on humans, and a suitable dosage would then be established as part of that process. Fortunately, this is already underway with two studies, one being conducted by: the Brigham Health Institute study and the other by the Washington University School of Medicine. Hopefully, as anticipated, these studies will show if NMN boosts NAD in humans, and has an effect on biomarkers associated with health longevity.


Your Takeaway

I threw a lot at you here, especially if you don’t supplement with NMN or NR, and don’t intend to. If that’s the case, I hope you watched the video, because it goes deep and wide about healthy longevity.

Regarding the safety and shelf life of NMN, remember these five things:

  1. NMN supplements have been extensively tested in mice, and have been shown to be safe and have effectively reduced various biometrics associated with aging.
  2. NMN is used by people because they either feel its beneficial effects, or expect it to make a positive difference in healthspan, as it has in mouse models.
  3. NMN supplements have been consumed by humans, including Dr. Sinclair, his family and thousands of consumers (including me) for years without ill effects. This point has been underscored by the Japanese study.
  4. The only published human NMN study to date did not test its effectiveness at improving health and longevity outcomes of those studied, but did find that NMN is safe to take as a supplement.
  5. Two human NMN studies are now underway and they are expected to test to see if NMN supplementation it effective at improving the health and longevity of people.


Last Updated on September 29, 2022 by Joe Garma

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Joe Garma

I help people live with more vitality and strength. I'm a big believer in sustainability, and am a bit nutty about optimizing my diet, supplements, hormones and exercise. To get exclusive Updates, tips and be on your way to a stronger, more youthful body, join my weekly Newsletter. You can also find me on LinkedIn, Twitter and Instagram.

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