Inadequate support: Some ingredients in tattoo ink are linked to a greater risk of cancer, but these risks were detected in those who had been exposed to the ingredient through other routes unrelated to the tattooing process. Limited existing research hasn’t yet found an association between tattoo ink and risk of lymphatic cancer.
Inadequate support: Zeolite is a mineral marketed as a dietary supplement to treat cancer and other health conditions, but there is no scientific evidence from human studies to support its use as a treatment for these conditions.
FULL CLAIM: “Tattoo ink contains cancer-causing chemicals and heavy metals which are linked to cancer, DNA damage, and chronic disease”; “the ingredients in the inks that are injected directly into our bloodstream are loaded with toxins”; a zeolite cure can remove these heavy metals from the body
REVIEW
Tattoos are a popular form of self-expression. The Pew Research Center estimated in 2023 that nearly one third of Americans have at least one tattoo, and more than 20% of Americans have more than one tattoo.
Tattoos are created by injecting ink into the skin’s dermis layer, which is the second layer beneath the outer epidermis. Needles are used to puncture the skin and deposit ink into the dermis layer to create a design. The healing process causes the skin to form a protective layer over the ink, ensuring the tattoo remains visible and permanent.
Tattoos have also become the subject of health controversial claims. In September 2024, an Instagram reel posted by Danica Walker, who had more than 492,000 followers at the time of writing, claimed that tattoo ink contains heavy metals and other carcinogenic (cancer-causing) ingredients. She cited a June 2024 study as evidence that tattoos are a risk factor for malignant lymphoma.
Walker further claimed that certain colors of ink are allegedly responsible for other medical conditions: for example, that red dye contains mercury and causes brain damage and mental illness, and that “[b]lue ink contains aluminum which is linked to alzheimers[sic]”.
At the time of writing, Walker’s reel had been viewed more than 734,000 times and received more than 13,000 likes.
There are some proven health risks associated with tattoos, such as allergies and infections. However, scientific evidence regarding the carcinogenic properties of tattoo ink is scarce, making it difficult to confirm or refute whether tattoo ink can in fact be a risk factor for cancer. Furthermore, the Instagram reel shared an incorrect statistic regarding lymphoma risk from the research it cited. We explain more below.
Figures cited in Instagram post doesn’t match the actual study results
In a voiceover in the Instagram reel, Walker claimed that a 2024 study from Nielsen et al. found that people who “got a tattoo done within the last two years” had an “81% increase of getting […] cancer of the lymph nodes”.
Nielsen et al. used what they defined as a population-based case-control study to address whether getting a tattoo was associated with increased risk of malignant lymphoma. To do this, they collected data from the Swedish National Cancer Register to identify all cases of malignant lymphoma occurring between 2007 and 2017, and data from the Swedish Population Register to match controls to each lymphoma case. They then collected data from a questionnaire on tattoo history to “estimate the incidence rate ratio of malignant lymphoma in tattooed individuals”.
But the 81% figure cited by Walker is misleading, since it’s only an assessment of the group with the highest lymphoma risk, not the entire population studied. When accounting for all study participants, Nielsen et al. found that[1]:
“[T]attooed individuals had a 21% higher risk of overall malignant lymphoma compared with non-tattooed individuals, and that the association was strongest for diffuse large B-cell lymphoma and follicular lymphoma.” [emphasis added]
Walker also made the claim that “the more tattoos you get, the higher your risk” of cancer. The study found no statistical significance of this observation—in other words, having more tattoos didn’t equate to a higher risk of malignant lymphoma diagnosis[1].
Science Feedback reached out to the authors of this study regarding the Instagram reel’s interpretation of their data, and will update this review pending their response.
Finally, Walker’s claim assumes that a correlation alone constitutes causation, a classic logical fallacy that can lead to misguided conclusions in medical research.
When two variables appear to move together—such as getting tattooed and receiving a malignant lymphoma diagnosis—it might seem intuitive to conclude that one causes the other. However, correlation merely indicates a relationship that could be coincidental, the result of a third variable, or a complex interplay of other factors. Science Feedback explained that correlation alone does not equal causation in greater detail in a previous article about adverse events occurring after getting vaccinated.
Tattoo ink does present certain health and safety risks, but more evidence is needed on its potential links to cancer
Tattoos are associated with certain health risks, such as rashes from allergic reactions and infections. These conditions can develop at any time, both immediately after getting a tattoo up to decades later.
It’s also true that tattoo ink contains ingredients classified as carcinogenic by the International Agency for Research on Cancer (IARC). The IARC explained:
“Chemical analyses of tattoo inks consistently identify substances classified by the IARC Monographs programme as carcinogenic (Group 1), probably carcinogenic (Group 2A), or possibly carcinogenic (Group 2B) to humans. The presence of these substances varies according to the colour of the ink. […] In addition, tattoo inks may contain various metals (e.g. arsenic, chromium, nickel, lead, and cadmium). […] These agents are associated with a higher risk of various types of cancer, such as cancers of the lung, kidney, liver, and bladder, depending on the substance. However, the IARC Monographs classifications were based mainly on studies investigating oral, dermal, or respiratory exposure routes, as occur in industrial workplaces (e.g. welding or dyeing), through the inhalation of tobacco smoke, or in other consumer products, such as hair dyes. The exposure route of tattoo inks injected directly into the dermis differs significantly from these more traditional uptake routes and remains unexplored in relation to its health effects.”
In brief, some ingredients in tattoo ink have been linked to cancer through certain routes of exposure. However, more research is needed to understand whether dermal injection of these ingredients in the amounts used in tattoos can increase cancer risk. Limited existing research hasn’t yet found an association between tattoo ink and risk of lymphatic cancer[1,2].
Efficacy of zeolite for “heavy metal detox” from tattoo ink lacks scientific evidence
Walker proposed zeolite as a solution for removing carcinogenic heavy metals that may be present in the body as a result of tattoo ink. Zeolite is a mineral which, according to the Memorial Sloan Kettering Cancer Center, has “not been shown to treat cancer”. They elaborate:
“Zeolites are also marketed as dietary supplements to treat cancer, diarrhea, autism, herpes, and hangover, and to balance pH and remove heavy metals in the body. However, there are no published human data to support these uses. Further, the FDA has issued several warning letters to distributors for misleading claims about zeolite products.”
Moreover, detox regimens promoted online are generally not based on scientific evidence and aren’t necessary for health promotion, which Science Feedback also explored in a previous article. It’s worth noting that Walker’s Instagram account links to a sales page for a zeolite supplement marketed as Touchstone Essentials Pure Body Extra. Walker’s TikTok account was previously deactivated for violating TikTok’s community guidelines regarding multi-level marketing (MLM) schemes.
Conclusion
Tattoos do come with some known health risks, such as rash from allergy or infections. Tattoo ink also contains ingredients that are classified by the IARC as carcinogenic, although this classification is largely based on evidence from other types of exposure that are distinct from exposure via tattoos.
However, there’s currently a lack of evidence that would allow us to reliably confirm or dismiss a causal link between tattoos and cancer. The study by Nielsen et al. cited by Walker makes it clear that while the authors found an association, this wasn’t sufficient evidence of a causal relationship. Evidence on the potential link between tattoo ink and cancer is currently limited and more research needs to be conducted to determine if there is a causal effect.
REFERENCES
- 1 – Nielsen et al. (2024) Tattoos as a risk factor for malignant lymphoma: a population-based case–control study. eClinicalMedicine.
- 2 – Warner et al. (2020) Tattoos and Hematologic Malignancies in British Columbia, Canada. Cancer Epidemiology, Biomarkers, & Prevention.
