Around 25% of adults aged 18 to 50 worldwide have at least one tattoo. For younger generations, this figure is almost twice as high. For many people, a tattoo is a personal story etched into the skin.
But while the debate usually revolves around the design, its meaning or whether later in life you will regret having it done, there is also another question from a health perspective: What are the long-term health consequences of having a tattoo?
Are tattoos bad for your health?
The short answer from a biological point of view is that tattoos are not entirely benign. When a needle injects ink under the skin, the body interprets this as an injury.
The tattooing process consists of thousands of such small perforations inserting pigments into a deep layer of the skin. This immediately activates the immune system to respond as it would to any other aggression from a foreign substance.
The ink does not stay only in the skin
A tattoo does not affect only the visible part; some of the ink travels through the lymphatic system. This is the internal network that helps the body defend itself from infection by removing substances it considers to be foreign.
Within minutes, the ink particles begin to move towards the lymph nodes, which are small organs that act as immune system filters.
After just 24 hours, these nodes will have already accumulated a visible amount of pigment. Most importantly, this ink is not removed; it can stay there for years or even a lifetime. In fact, healthy lymph nodes near tattoos in some people take on a bluish or dark colouration due to ink absorption.
The immune system doesn’t stop
When the ink reaches the lymph nodes, the immune system tries to do its job. The main cells responsible for this are called macrophages, which absorb and neutralise foreign substances.
The problem is that tattoo ink is especially difficult to eliminate. Macrophages can capture it, but they cannot fully break it down. Over time, these cells eventually die, and their death triggers an inflammatory response.
At first, this inflammation is part of the normal healing process. However, studies have shown that this does not always resolve completely. On the contrary, there is evidence of persistent inflammation in the lymph nodes months after tattooing.
In other words, a tattoo can leave behind ongoing inflammation in a key area of the immune system. And chronic inflammation is known to be a factor associated with various long-term diseases.
Are tattoos carcinogenic?
This is probably the question that causes the most concern—and is also the most complex to answer. A tattoo cannot be said to directly cause cancer, but there are several factors that warrant caution.
What does tattoo ink contain?
Although European regulations restrict many hazardous substances, it is true that tattoos can contain compounds recognized scientifically as potentially harmful:
- Black ink may contain polycyclic aromatic hydrocarbons, such as benzo(a)pyrene, which is classified as a carcinogen.
- Coloured inks often include azo compounds, which can break down over time and release carcinogenic substances.
- Heavy metals like cadmium and mercury have also been detected.
Inserting these substances into the body and retaining them for years in the lymph nodes may have more biological significance than has previously been considered.
What do the most recent studies say?
A study published in 2025 found that tattooed people have a higher risk of:
- Skin cancer.
- Lymphoma, especially for large tattoos (bigger than the palm of the hand), with the risk in some cases being more than double.
Researchers point to a particularly concerning combination: potentially carcinogenic substances accumulating in the lymph nodes together with chronic inflammation. Over time, this situation may lead to alterations in the cells of the immune system.
However, studies conducted in this field have had significant limitations; so their conclusions should be interpreted with caution and need to be confirmed by more robust research in the future.
Detecting cancer early
However, there is one clearly documented risk: Tattoos can make the early detection of skin cancer more difficult.
Tattoo ink can mask changes in moles or skin lesions, making it more difficult to identify melanoma at an early stage, when treatment is most effective. In addition, ink that accumulates in the lymph nodes can be mistaken for metastases on imaging tests, which may complicate diagnosis.
Also, tattoos can trigger local inflammatory reactions of varying types and intensity, either due to the substances used or to the skin trauma inherent in the procedure. Tattoos may also be associated with both local and systemic infectious processes, especially when not performed under adequate hygienic conditions.
Medical reasons to consider before getting a tattoo
There are other health-related reasons besides cancer that are often not considered.
The immune system may function differently
Lymph nodes are not merely “storage sites”—as is sometimes thought— they are immune system coordination centres. When chronically inflamed, containing damaged macrophages, the body’s response to infections or vaccines may change.
This has been observed in some studies involving vaccines:
- The response to mRNA vaccines, such as the COVID-19 vaccine, was lower in animals.
- In contrast, some inactivated vaccines, such as the influenza vaccine, produced a stronger response, probably because inflammation acted as an “additional stimulus”.
Such an unpredictable effect is a sign that tattoo ink is not immunologically neutral.
Allergic reactions and other problems
Allergic reactions—especially to red pigment—may appear months or even years after getting a tattoo. Also, persistent inflammation and discomfort during certain procedures, such as magnetic resonance imaging (MRI), have been reported.
Healthcare professionals advise against having a tattoo, particularly for those who are:
- Pregnant or breastfeeding
- Immunocompromised
- Suffering skin conditions, such as psoriasis or vitiligo
- At risk of endocarditis, such as patients with congenital heart disease, or those with artificial heart valves or implanted cardiac devices
Tattoos and autoimmune diseases
In people with autoimmune diseases, tattooing can act as a trigger.
In conditions such as psoriasis or vitiligo, the trauma caused by the needle can lead to lesions appearing directly over the tattoo. This is known as the Koebner phenomenon.
Sarcoidosis is one of the diseases most frequently associated with tattoos. In some cases, the inflammatory reaction to pigments is the first clue to an underlying systemic disease.
So, tattoos: yes or no?
Getting a tattoo is a personal decision, but it is not biologically neutral. The ink does not disappear and may interact with the immune system for many years.
Choosing the size, location and type of tattoo is essential. The procedure must also be carried out by a certified professional in a facility that strictly complies with all hygiene and health requirements.
For people who already have tattoos, the main recommendation is clear: monitor your skin, examine yourself regularly and seek medical advice if any suspicious changes are observed.
For those still considering one: caution is recommended. It must be understood that what happens inside the body is just as important as any design chosen to display on the skin.
