The 12 characteristics of aging
Aging is a process that becomes visible throughout the body and affects how you feel, move, and recover. Scientists see this as being driven by twelve hallmarks that show what changes at the cellular level and why certain processes become slower or less efficient.
These hallmarks make clear what happens during aging and where there is still room for support. If you understand how they work, you can better see where you can make an impact yourself. In this article, we take you through these twelve hallmarks and what they mean for your health.
What are the 12 hallmarks of aging?
The twelve hallmarks of aging describe processes that slowly change as you get older. In a comprehensive study in the journal Cell, López Otín and colleagues show that the twelve hallmarks together form the framework scientists use to understand aging.¹
These processes constantly influence one another and determine how well your body can carry out functions such as repair, energy balance, and stress responses. When those systems come under pressure, other processes can speed up or weaken, and aging becomes visible. This creates a chain reaction that affects how your cells function.
In the following sections, we guide you step by step through each of these twelve hallmarks. This way, you can see exactly what is happening in your body, why these processes matter, and how they influence one another.
1. Genomic instability
Genomic instability means that the DNA in your cells becomes less and less stable because damage occurs that is no longer properly repaired. That damage can come from external factors such as UV light and pollution, but also from natural processes within the cell itself, such as mistakes during division.
When repair mechanisms weaken, small damage accumulates. This not only hinders how cells function, but also sets in motion processes that accelerate aging. Research by Martinez in Longevity Review shows that maintaining healthy and well-protected DNA (the genome) actually helps keep cells healthy and slows down the harmful effects of aging. Protecting your DNA is therefore an important foundation for healthy aging. ²
In DNA repair,\ playing NAD+-dependent enzymes a role. A healthy NAD level supports these processes. Want to know how you can supplement it? Then take a look at our range NMN products.
2. Telomere shortening
Telomeres are small protective caps at the ends of chromosomes. They ensure that DNA stays intact during each cell division. With every division, they become a little shorter. Once they become too short, a cell can no longer divide and is damaged more quickly.
According to research by Huang and Hu, this process plays an important role in cellular aging. They describe telomere shortening as one of the core mechanisms that becomes visible as you age and that, when it happens more rapidly, contributes to faster aging processes. Maintaining healthy telomeres helps cells function well for longer and thus supports resilient aging.³
3. Epigenetic changes
Epigenetics determines which genes are switched on and which are not. You can see it as a kind of switch that helps cells start the right processes at the right time. As you age, this fine regulation becomes disrupted. Genes are then activated too early, too late, or no longer at all, which can lead to cellular disruption and a body that functions less smoothly.
4. Loss of proteostasis
Proteostasis is the system by which cells keep their proteins healthy. They make new proteins, ensure they fold into the right shape, and clear out damaged proteins. As you age, this system works less well. Broken or misfolded proteins then accumulate, causing cells to function less efficiently.
These repair processes cost a lot of energy and depend on NAD. To support that natural balance, some people choose to top up their NAD level, for example with a pure NMN supplement.
5. Disabled macro autophagy
Autophagy is the cell’s cleanup system. It clears out damaged components so cells stay healthy. When this process works less well, waste builds up and cells become more vulnerable to aging more quickly. Tartiere and Freije show that a baseline level of autophagy is needed to keep cells vital. If this fails, energy and protein balance are disrupted and cellular aging can accelerate. ⁴
Autophagy costs a lot of energy and uses NAD. That’s why some people support this process by topping up their NAD level, for example with a pure NMN supplement.
6. Deregulated nutrient sensing
Nutrient sensing is the system by which cells detect how much nutrition and energy are available. Based on that, they decide whether the body should store, burn, or repair. As you age, this system becomes less accurate. Cells then respond more slowly or incorrectly to nutrition, which can contribute to metabolic problems that are more common later in life.
7. Mitochondrial dysfunction
Mitochondria are the cell’s energy sources. As you age, they work less efficiently and produce more harmful byproducts, such as free radicals.
According to López Otín and colleagues, this decline is an important hallmark of aging, because impaired mitochondrial function affects metabolism, protein quality, and cells’ ability to recover. When mitochondria function less well, cells recover more slowly and become more susceptible to damage.
8. Cellular senescence
When cells have accumulated too much damage, they would normally be cleared away by the body. But as you get older, that becomes less effective. Some damaged cells still remain. They no longer divide, but they do remain active in the tissue. According to the Lifespan Research Institute, these so-called “senescent cells” can send out harmful signals that weaken the surrounding tissue and thereby accelerate the ageing process. ⁵
Over the years, the number of these zombie cells increase, causing organs and tissues to function less well. This makes cellular senescence an important hallmark of ageing.
9. Stem cell exhaustion
Stem cells are the source of new cells. They renew the skin, muscles, blood, and many other tissues. With ageing, their numbers decrease and they become less active. This is because over time they accumulate damage and stress signals, causing their ability to divide to slowly decline. You can see this in slower recovery, less resilience, and a loss of muscle mass.
10. Altered intercellular communication
Cells constantly send signals to each other to keep processes in the body running properly. As you age, this communication becomes disrupted. According to Tartiere and colleagues, signals can then be transmitted too weakly, too strongly, or incorrectly, which ultimately triggers responses that reinforce the ageing process.⁴
A decline in NAD plays a role here, because cells need it to transmit signals and direct repair. Because this process depends on NAD, some people choose an NMN supplement to give their body extra support with pure NMN products.
11. Dysbiosis
Dysbiosis means the balance in the gut microbiome is disrupted. The intestines contain billions of bacteria that help with digestion, the production of beneficial substances, and support of the immune system. As you get older, this balance can shift.
When beneficial bacteria decrease and less beneficial varieties increase, the gut barrier weakens and inflammatory signals can increase. This affects energy, immunity, and recovery, meaning dysbiosis can play a role in speeding up ageing processes.
12. Chronic inflammation
Chronic inflammation is a mild, persistent inflammatory response in the body. Normally, inflammation helps repair damage or tackle pathogens, but when this process stays continuously active, the balance is disrupted. This occurs more often with ageing because cells get damaged and repeatedly send signals that activate the immune system.
This continuous inflammatory pressure makes tissues more susceptible to damage and can slow recovery. That’s why chronic inflammation is seen as an important hallmark of aging.
Why are the twelve hallmarks of aging important for you?
The twelve hallmarks show what changes in your body as you age and which processes you can influence yourself. They provide insight into why you sometimes have less energy, recover more slowly, or notice changes in your skin, muscles, or memory.
It’s important to note that these processes are not determined by genetics alone. Your lifestyle has a strong influence on how quickly or slowly these hallmarks become visible. That makes them a valuable guide for anyone who wants to age more healthily.
What does that mean for you?
The hallmarks make it clear that your body and mind change because various processes at the cellular level gradually shift. Think of less energy due to less efficient mitochondria, stiffness due to reduced repair, and a less sharp memory due to changes in cell communication.
They also show that you have more influence than you might think. By adjusting your habits, you can support many of these processes:
- By eating nutritious food and exercising regularly, your mitochondria work better and your energy level stays more stable.
- By reducing stress, you limit inflammatory signals and epigenetic disruptions that accelerate aging.
- By sleeping well and enough, you support recovery, protein balance, and the removal of waste products.
These insights highlight how important prevention is. The earlier you make healthy choices, the better you can slow these processes and support your cellular resilience.
For many people, this is the start of their longevity journey. Supplementation can provide extra support. Anyone who wants to boost their NAD level can see whether a pure NMN supplement fits their lifestyle. View our selection NMN products for more information.
Sources:
¹ López Otín, C., Blasco, M. A., Partridge, L., Serrano, M., Kroemer, G. (2023). Hallmarks of aging: An expanding universe. Cell. https://www.sciencedirect.com/science/article/pii/S0092867422013770
² Martinez, C. (2025). Hallmark of Aging Reviewed: How Genomic Instability Shapes Our Lifespan. Longevity Review. https://longevityreview.com/2025/02/21/hallmark-of-aging-reviewed-how-genomic-instability-shapes-our-lifespan/?utm_source=chatgpt.com
³ Huang, B., Hu, X. (2025). Causality of Aging Hallmarks. Aging and Disease. https://www.aginganddisease.org/EN/10.14336/AD.2025.0541
⁴ Tartiere, A. G., Freije, J. M. P., López Otín, C. (2024). The hallmarks of aging as a conceptual framework for health and longevity research. Frontiers. https://www.frontiersin.org/journals/aging/articles/10.3389/fragi.2024.1334261/full
⁵ Lifespan Research Institute (n.d.). Why We Age: Genomic Instability. https://www.lifespan.io/topic/genomic-instability/
