What’s the deal with the sale of NMN in the US?

Dietary supplements purported to support longevity have become big business in recent years.

One of the most closely followed is nicotinamide mononucleotide (NMN) and its availability status changed in the US in 2022, causing ongoing confusion for consumers.

The background to NMN

Some scientists believe it’s possible to boost our levels of NAD, a coenzyme that’s present in every cell in our bodies, using NMN.

NAD provides fuel for our mitochondria to function, and mitochondria are often referred to as the powerhouse of our cells and are essential to our health, energy and longevity.

But our levels of NAD decline with age and the theory is by boosting it we can improve our cell function and reduce some of the negative effects of aging.

NMN is derived from vitamin B3 and there are other vitamin B3 related supplements out there including nicotinamide riboside (or NR) and niacin.

As a group of supplements there is quite a bit of debate in the scientific community about which one most readily converts to NAD in the body, with some suggesting one is better over another, others saying they do much the same thing, and others questioning whether supplementing with a B3 derivative would have much of a beneficial effect at all.

While it is available to buy as a dietary supplement in many parts of the world, the situation is different in the US where it is being investigated for licensing as a potential prescription drug.

While the Food and Drug Administration considers its recategorization it has been precluded from being defined as a dietary supplement which prevents it from being sold as such.

Why is it still being sold by some retailers in the US?

At the time of writing this article, some NMN products continue to be sold in the US.

Technically speaking any business in the US selling NMN as a dietary supplement is violating the FDA ruling and could be subject to fines if it is enforced.

The FDA could choose to exercise ‘enforcement discretion’ to products containing NMN which are still labeled as dietary supplements.

This was applied to the sale of N-acetyl-L-cysteine (NAC) after the FDA concluded it should be excluded as a dietary supplement because of its drug status.

The agency applied enforcement discretion because it noted there were no safety issues thus far around its use as a dietary supplement, which had been the case for over 30 years, and in light of strong demand.

It has yet to make any further announcement regarding NMN, and is coming under pressure from representative bodies including the Natural Products Association to clarify the position regarding regulatory status.

NMN evidence

Proponents of NMN site a multitude of studies, but they’re mainly on mice or rats.

The studies concluded that boosting NAD levels with NMN led to improved insulin sensitivity in diabetic mice, restored gene expression linked to circadian rhythm which in other words improves our sleep, and found a reduction in inflammation and oxidative stress, both cornerstones of aging.

It was also shown to suppress age-related weight gain in mice, protect older organs and improve cognitive function, and increase their endurance levels in exercise.

And it was found to have restored the number of blood capillaries and capillary density to those seen in younger mice and resulted in increased blood flow to the muscles and significantly greater exercise capacity in the treated mice compared to untreated mice.

But in general the human clinical trial results have not been as dramatic as those seen in mice to date.

NMN is still available for sale as a dietary supplement in the UK, with suppliers shipping to the US.