Longevity supplements are sold as helping prevent ageing. But do they have any long-term benefits or increase lifespan?

Promoters of longevity supplements claim they ‘boost daily vitality’ and ‘improve cellular health’, but what does the evidence say? Composite: Guardian Design/Getty Images

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.