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There are many acronyms you might find on the packaging of so-called longevity supplements, promoted by influencers for their ability to “repair DNA” and assist in “anti-ageing”.
NRC (nicotinamide riboside chloride) and NMN (nicotinamide mononucleotide) are two of them – both precursors or “building blocks” for NAD (nicotinamide adenine dinucleotide), a naturally occurring molecule in the body. Trimethylglycine (TMG) is another and is sometimes added to “support” other ingredients.
Packaged together, these ingredients are supposed to “boost daily vitality” and “improve cellular health”, according to their promoters.
But is there any evidence to support these claims?
What are longevity supplements?
While some longevity supplements contain multiple ingredients in one tablet, others promote “stacking” – that is, buying different products and ingredients and taking them together for an optimum longevity boost.
Prof Oliver Jones, an internationally recognised expert in analytical science with RMIT University, says NAD is involved in many chemical reactions in the body, including energy production and DNA repair.
“Your body has two main ways to get NAD,” he says.
“It can create it from scratch … or it can recycle it from other compounds. Some people suggest one can boost NAD production by providing the precursor compounds.”
The reason NAD-promoting supplements keep getting pushed as anti-ageing is twofold, Jones says, “Because NAD is part of a lot of essential biochemical processes in the body, and because concentrations of NAD are reported to decline as we age.”
What the evidence says
While clever marketing makes it sound like products containing these or other building blocks can increase longevity, “the likelihood that any single compound among the many thousands in the body is responsible for all ageing is pretty much zero”, Jones says.
“Even if NAD concentrations did decline with age, that would not mean that the decrease in NAD caused the ageing,” Jones says. “There are plenty of biochemical changes associated with ageing but that does not mean the changes caused the ageing.”
One Instagram ad states that “NAD levels increase by 51% in 14 days” after taking a particular longevity supplement. But Jones says increases in a single biomarker don’t always equate to meaningful changes, such as reduced disease.
“While 51% sounds like a large increase, it only means your original concentration went up by half the original amount,” he says.
“For example, if you start with 0.25mg of a compound, increasing it by 51% gives you 0.38mg, which is not much more. It is easy to use a percentage increase to make something sound large.”
The question we should ask is not “do NAD concentrations increase or not” but “does it matter if they increase or not”, he says.
Prof Bruce Neal, a physician and executive director of the George Institute for Global Health, says to determine that “you need large, well-designed trials that show real outcomes, such as fewer heart attacks, better physical function, longer life”.
“For these products, that kind of evidence just doesn’t exist.”
Very few human studies have been done
Danielle Shine, an accredited dietitian, nutritionist and PhD candidate researching nutrition misinformation on social media, says much of the enthusiasm for longevity products is “based on animal studies, mainly involving rodents, which rarely translate reliably to humans, especially for complex outcomes like ageing or long-term health”.
“Humans aren’t rodents,” she says. “We metabolise compounds differently, live in far more variable environments and age in fundamentally different ways.”
She said a few small NMN studies in adults aged 40-65 reported minor improvements in subjective energy or walking distance “but there’s no evidence that these short-term changes translate into long-term health benefits or increased lifespan”.
Neal adds that combining ingredients in the hope the right “stack” will boost health “is just another clever way of getting people to spend more money on things that probably won’t help them”.
“If you think the supplement offsets drinking more or smoking, that’s also a problem.”
So what actually improves longevity?
Shine says maintaining a healthy and well-balanced diet, drinking water, exercise that includes resistance training, getting enough sleep, managing stress, nurturing social connections, avoiding harmful substances and protecting your skin with broad-spectrum sunscreen all help.
“Keeping up with preventative healthcare, including vaccinations, routine check-ups and evidence-based screening tests” is also important, she says.
“No supplement can match or replace these foundational habits for supporting overall health and longevity.”
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Melissa Davey is Guardian Australia’s medical editor
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Antiviral is a fortnightly column that interrogates the evidence behind the health headlines and factchecks popular wellness claims
