NAD+ in 2026: three scientific advances that change what we knew

NAD⁺ is one of the most talked-about molecules in longevity, and also one of the most poorly explained. In recent months, three papers have been published that bring real clarity to the debate: they show which precursors genuinely raise NAD⁺, what role the gut plays, and why a blood test isn't the “clock” some claim it to be. Here's the honest rundown, no exaggeration.

🧬 Longevity Science · 6 min read · Educational information

Before we start: what is NAD⁺

NAD⁺ (nicotinamide adenine dinucleotide) is a coenzyme present in all your cells. It's involved in extracting energy from food and in cellular maintenance processes. The body makes it from several forms of vitamin B3, known as precursors: nicotinamide (NAM), nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN), among others.

1. The gut was the missing piece

A trial published in Nature Metabolism in January 2026 compared three precursors head-to-head in people for the first time. Sixty-five healthy adults took NR, NMN, nicotinamide or placebo for 14 days.

• NR and NMN raised blood NAD⁺ in a similar way. Nicotinamide did not do so in a sustained manner.
• In the lab, gut microbiota converted NR and NMN into nicotinic acid, another form of vitamin B3, and this acid turned out to be the compound that raised blood NAD⁺ the most.
• The authors propose a model in which the gut is part of the pathway: NR and NMN would raise NAD⁺ largely through what our bacteria do with them.

It's a shift in perspective: gut health could influence how each person responds to these precursors. The study was funded by Nestlé Research, as the authors themselves declare.

2. Blood NAD⁺ is not an ageing clock

It's often repeated that “NAD⁺ falls with age”. A paper from May 2026 in Nature Metabolism, with seven European cohorts (two of them in Valencia and Murcia), put this to the test with a very rigorous measurement method. Blood NAD⁺ remained remarkably stable with age and did not change with lifestyle interventions either; however, it did rise with NR supplementation.

The practical conclusion is important: a blood NAD+ test cannot be used as a marker of your “biological age”, nor to measure whether your habits are working. What happens in other tissues, such as muscle or the brain, remains an open question.

3. NR in accelerated ageing: Werner syndrome

Werner syndrome is a rare inherited disease in which ageing is accelerated and in which an NAD⁺ deficit has been described. Chiba University (Japan) published a double-blind, crossover trial in Aging Cell: each patient took NR or placebo for 26 weeks and then switched to the other.

• There were no serious adverse effects with NR, which was the primary endpoint.
• Arterial stiffness improved (CAVI index) and the area of skin ulcers was reduced.
• Blood creatinine dropped, an indicator related to kidney function.

It's a small study, in a specific condition and with NR supplied by a manufacturer, so its results cannot simply be extended to healthy people. But it's among the first placebo-controlled trials in a human model of accelerated ageing.

What all three tell us together

• The precursors NR and NMN raise blood NAD⁺, and the gut plays a part in that process.
• Blood NAD⁺ is not a good indicator of ageing: be wary of tests that claim otherwise.
• Potential benefits are being studied in specific populations, with promising but still limited results.

NAD⁺ science is moving fast, and with ever more rigour. If you'd like to understand NR properly from the start, take a look at what NR is, a guide from scratch. And if you'd like to discover the NR we formulate at LifeXpan, here's NR PURO.

Food supplements should not be used as a substitute for a varied and balanced diet and a healthy lifestyle. This article is for educational purposes only and does not replace the advice of a healthcare professional.