NAD+ and Healthy Ageing: Mitochondria, Sirtuins and Longevity

NAD+ plays an important role in cellular energy metabolism and in the activity of NAD+-dependent enzymes such as sirtuins, and while NAD+ levels appear to change with age, no supplement can reverse ageing.

We increasingly think about ageing in two ways. There is chronological age, the number of years you have lived, and biological age, a sense of how well your cells and systems are actually functioning. Longevity science is really about narrowing the gap between the two, and one coenzyme keeps appearing at the centre of that conversation: NAD+.

This is a clear, science-led look at why NAD+ matters for healthy ageing, what sirtuins and PARPs actually do, and where the evidence is strong versus still emerging. It is educational, not a promise to slow your ageing.

• Why is NAD+ linked to ageing?

NAD+ plays an important role in cellular energy production, including within the mitochondria, and is also required for the activity of sirtuins, a family of proteins involved in processes such as cellular maintenance and repair. Both rely on NAD+ to function normally.

• Does NAD+ really decline with age?

It is widely reported to fall with age, though the exact size of the decline varies between studies and tissues.

• Can NAD+ reverse ageing?

No. No supplement reverses chronological ageing or extends lifespan. The honest aim is supporting cellular health, or "healthspan".

• What can actually be claimed?

The authorised UK health claim belongs to niacin (vitamin B3): it contributes to normal energy-yielding metabolism and the reduction of tiredness and fatigue.

As we get older, the amount of NAD+ available inside our cells is thought to fall. A major 2021 review in Nature Reviews Molecular Cell Biology on NAD+ metabolism and its roles in cellular processes during ageing describes how shifting NAD+ levels affect the cell's energy and repair systems over a lifetime.5

It is worth being precise, though. The popular claim that NAD+ "halves by middle age" is not as settled as it sounds. A 2022 review in Nutrients on whether the age-related NAD+ decline is a universal truth found that the evidence varies considerably between tissues and studies.4 The fair summary is that NAD+ availability tends to decrease with age, but the exact amount is still debated.

• Cells depend on NAD+ for energy and repair.

• NAD+ availability is thought to decline with age.

• Lower NAD+ leaves less to support the cell's maintenance systems.

Research, much of it in laboratory and animal models, has also linked falling NAD+ to less efficient communication between the cell's nucleus and its mitochondria, which are the compartments that produce energy.5 You can read more about NAD+ levels in the body in our dedicated explainer.

Two families of NAD+-dependent proteins do much of the work people associate with healthy ageing. Both need NAD+ to function, which is why NAD+ is so central to this science.

Sirtuins are a family of proteins and they help regulate processes such as DNA repair, inflammation and circadian rhythms. Crucially, sirtuins are NAD-dependent: without enough NAD+, they cannot do their job. You can see a plain definition in our glossary entry on sirtuins.

PARPs (poly ADP-ribose polymerases) are enzymes that repair damaged DNA. To do this, they consume NAD+, and when a cell is under stress, PARPs can use up large amounts of it.

This sets up what researchers describe as a kind of tug-of-war. As we age and cellular damage accumulates, PARPs draw more heavily on the cell's NAD+ to carry out repairs, which can leave less NAD+ available for the sirtuins.5 It is one reason NAD+ availability is such an active area of ageing research.

Alongside repair, NAD+ is essential to energy. Your mitochondria use it as a helper molecule to turn food into ATP, the fuel your cells spend to do everything from thinking to moving.

On the benefit itself, it is important to stay within what is authorised. Because NAD+ belongs to the vitamin B3 (niacin) family, the authorised UK health claim for this nutrient group is that niacin contributes to normal energy-yielding metabolism and the reduction of tiredness and fatigue.2 The NHS notes that niacin helps the body release energy from food.1 That is the honest, tangible frame: supporting normal energy metabolism, not slowing the ageing process.

Supporting NAD+ is not only about supplements. The foundations come first, and they are genuinely effective.

Regular exercise and periods of fasting are both associated with the body producing more of its own NAD+, and good sleep and a balanced diet support healthy metabolism more broadly. Our guide to ways to support healthy biological ageing covers these in more depth.

If you choose to supplement, formulation is one consideration. Vivere's liposomal NAD+ capsules use a liposomal, enteric-coated design intended to protect the direct coenzyme through the gut, making them a convenient daily option. We explain the mechanism in our guide to how liposomal delivery works, and cover the wider evidence on whether liposomal NAD+ capsules really work.

For those who prefer to bypass digestion, Vivere's NAD+ injection pens deliver NAD+ subcutaneously. If you are weighing the two, our guide on how NAD+ capsules and injections compare sets out the trade-offs.

Keeping it honest. NAD+ is fascinating longevity science, but the human evidence for supplementation is still developing. A 2025 review in Nature Metabolism on NAD+ precursor supplementation in human ageing notes that raising NAD+ is achievable while clear functional benefits in people remain limited.3 Treat any brand promising to reverse ageing with real caution.

"Longevity research is an exciting area, although some of the claims around it can be exaggerated. We know that NAD+ plays an important role in energy metabolism, and NAD+ levels appear to change with age, although these changes can vary between individuals and different tissues. The underlying cell biology is genuinely fascinating too: both sirtuins and PARPs use NAD+ for their activity. However, this does not mean that NAD+ supplementation can reverse ageing. There is currently no evidence that supplementation can do that. To support healthspan, we should focus on the foundations of healthy living first, including good sleep, regular movement and a balanced diet, with further supplementation, including NAD+, considered as part of a broader approach when appropriate. Most importantly, it is worth keeping expectations realistic. Healthy ageing is a marathon of good habits, not a single miracle capsule."

No. No supplement can reverse chronological ageing or stop the clock. What NAD+ does is support the cellular systems involved in energy and maintenance, such as the mitochondria and the NAD-dependent sirtuins. The authorised nutrition claim in this area is that niacin contributes to normal energy-yielding metabolism and the reduction of tiredness and fatigue.

NMN is a precursor that your body must first convert into NAD+, and it is currently undergoing regulatory assessment as a novel food in the UK. Vivere uses direct beta-NAD+, which delivers the fully formed coenzyme without relying on that conversion step. Our guide to NAD+, NMN and NR compared explains the difference.

There is no set age. NAD+ is thought to decline gradually through adulthood, so many people start in their 30s or 40s as part of a proactive routine. It is a personal choice rather than a medical rule, and the fundamentals of sleep, exercise and diet matter at any age.

Chronological age is simply how many years you have lived. Biological age is a way of describing how well your cells and body are functioning, which can be better or worse than your years suggest. Longevity science focuses on supporting your biological age through healthy habits, and NAD+ is part of that underlying cell biology.

NAD+ is central to how cells turn food into energy, and the authorised claim for the niacin family it belongs to is that it contributes to normal energy-yielding metabolism and the reduction of tiredness and fatigue. It is best seen as foundational support taken consistently, not a quick fix for age-related tiredness.

"When it comes to healthy ageing, I think it is helpful to look at the bigger picture. NAD+ plays an important role in normal cellular processes, including energy metabolism, and maintaining healthy NAD+ biology is an interesting area of ongoing research. However, no single supplement can replace the foundations that support healthspan over time. Prioritising good sleep, regular physical activity, a nutritious and varied diet and other healthy lifestyle habits should remain the starting point. If you choose to supplement, NAD+ can be considered as one part of that wider approach, alongside realistic expectations and an understanding that the science is still evolving. Healthy ageing is built gradually, through consistent choices that support your health over the long term."

About the author. This guide was reviewed by Yusra Serdaroglu Aydin, MSc RD, Head of Nutrition at Vivere. It draws on NHS guidance, the Great Britain Nutrition and Health Claims Register, and peer-reviewed research into how NAD+ supports the body. Wondering whether capsules deliver? See the evidence on liposomal NAD+, or how NAD+ relates to everyday energy and tiredness.

This article is for general information and education only and is not medical advice, and does not diagnose, treat or prevent any condition. Food supplements are not a substitute for a varied, balanced diet and a healthy lifestyle. If you are pregnant, breastfeeding, taking medication or managing a health condition, speak to your GP or pharmacist before starting any new supplement.

1. NAD+ precursor supplementation in human ageing: clinical evidence and challenges. Nature Metabolism, 2025. Notes that oral supplements can raise circulating NAD+ while measurable functional benefits in humans remain limited.

2. Age-Dependent Decline of NAD+: Universal Truth or Confounded Consensus? Nutrients, 2022. A balanced appraisal of the evidence that NAD+ falls with age, noting variation between tissues and studies.

3. NAD+ metabolism and its roles in cellular processes during ageing. Nature Reviews Molecular Cell Biology, 2021. A comprehensive review of how NAD+ supports mitochondrial energy, sirtuins and PARPs, and how its metabolism shifts with age.

1. Niacin (vitamin B3): what it does and how much you need. NHS. Niacin helps the body release energy from food; recommended daily amounts for adults aged 19 to 64 are 16.5mg for men and 13.2mg for women.

2. Great Britain Nutrition and Health Claims (NHC) Register. Department of Health and Social Care. Lists the authorised claims that niacin contributes to normal energy-yielding metabolism and to the reduction of tiredness and fatigue.