Anti-ageing supplements are everywhere, from advertising campaigns to social media feeds. Promising everything from increased energy to a longer life, they come in many forms, from powders containing multiple ingredients to single-nutrient capsules.

One molecule in particular, NAD , has attracted growing interest, with claims it can boost energy, improve vitality, slow ageing and even help us live longer.

But does the science support these claims? And can NAD supplements really help us age more healthily?

NAD (short for nicotinamide adenine dinucleotide) is found in every cell in our bodies. It plays an essential role in helping our cells turn food into energy. Without it, many of the processes that keep us alive would be unable to function.

NAD also supports numerous enzymes and proteins, including sirtuins, which help regulate inflammation, DNA repair and the function of mitochondria, the structures responsible for producing much of the energy our cells need.

Research suggests that NAD levels decline as we get older. This is partly because damage to our DNA accumulates over time, activating enzymes that use up NAD more quickly. Another enzyme, called CD38, also becomes more active with age and inflammation, increasing NAD use. Meanwhile, our cells may become less efficient at producing it.

The extent of this decline varies between people and different tissues, with some studies suggesting that NAD levels may fall by between 10% and 80% as we age.

Lower NAD levels have been linked........

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