NR vs NMN: why we chose NR

Walk into the world of longevity supplements and you'll soon meet two sets of initials: NR and NMN. Both are sold as ways to raise NAD⁺, a molecule every cell needs to turn food into energy and to maintain itself (see NAD⁺ and NR: what we know, and why we built a network).

Online, NMN often wins the argument with a diagram. It sits one step closer to NAD⁺, so it must be better. Biology is rarely that tidy.

Two molecules, one family

NR and NMN are close cousins. NMN is NR with a phosphate group attached. Inside the cell, NR is turned into NMN, and NMN is turned into NAD⁺. On paper, NMN skips a step.

1. The research record

NR was the first of the two shown to be orally available and to raise NAD⁺ in people, in a 2016 study.¹ Since then, randomised human trials have tested NR from 100 to 2,000 mg a day, for weeks to months. They consistently show higher NAD⁺ in the blood, and they've built a well-characterised short-term safety profile.²⁻⁴

NMN's human trials are newer and fewer. Some are promising: in one small trial, 250 mg a day improved muscle insulin sensitivity in women with prediabetes.⁵ But the overall body of evidence is younger.

Neither has yet shown that it makes healthy people live longer, or reliably feel better. On outcomes you'd notice, NR's results are mixed too: some trials show nothing, one in peripheral artery disease showed a modest benefit.⁴ Honesty applies to both.

2. The legal status in the UK

This one is clear-cut.

• NR chloride is an authorised novel food in Great Britain for food supplements, up to 300 mg a day for adults (not in pregnancy or breastfeeding).⁶
• NMN isn't authorised in Great Britain. An application to the Food Standards Agency is still under assessment.⁷ The European Commission has also recorded NMN as unauthorised in its enforcement reports.⁸

A novel-food authorisation means a substance has been through a safety assessment for a defined use. For a product sold in the UK, that's the standard we work to.

3. How each gets into the cell

Here's where the "one step closer" diagram breaks down.

NMN is a larger, electrically charged molecule. Much of the evidence suggests it doesn't cross cell membranes easily: outside the cell it's generally converted to NR, which enters, and is then rebuilt into NMN inside.⁹ A dedicated NMN transporter was reported in mice in 2019, but whether it plays a meaningful role, and in humans, is still debated.¹⁰

NR, by contrast, enters cells as it is, through transporters that carry molecules of its kind. Then it's converted to NMN and NAD⁺.

So the step NMN supposedly skips is, in many cases, one it has to take in reverse first.

What this doesn't mean

• It doesn't mean NMN "doesn't work". It feeds the same pathway.
• It doesn't mean NR is proven to do more. No head-to-head trial has compared them on health outcomes.
• It doesn't mean more is better. In GB, NR's authorised use stops at 300 mg a day.

Why 4VIA uses NR

We chose NR because it has the longer human research record, it's authorised for sale in GB, and it reaches the cell by the simpler route. In 4VIA, it's one part of an NAD⁺ network: 125 mg of NR, microencapsulated to protect it in the powder, alongside niacin, the B-vitamin cofactors B2 and B6, CoQ10, trans-resveratrol and PQQ.

The strongest human evidence for raising NAD⁺, legal status in the UK, and a direct route into the cell. That's why NR is in 4VIA.