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To dye for? Jury still out on tattoo ink causing cancer

Scientists have recently raised alarm over the possibility that some inks used for tattoos contain cancer-causing chemicals. To make matters worse, some pigments come as small particles called nanoparticles…

There’s no doubt that some of the chemicals in tattoo ink have been associated with cancer – but it’s a bit more complicated. Image from

Scientists have recently raised alarm over the possibility that some inks used for tattoos contain cancer-causing chemicals.

To make matters worse, some pigments come as small particles called nanoparticles that could easily enter the bloodstream and accumulate in organs such as the spleen and kidneys. These organs filter impurities and their failure may ultimately increase the risk of cancer.

But should we be worried? Let’s look at the evidence.

Tattoo ink

There is no doubt some of the chemicals in tattoo ink have been associated with cancer.

The red colours can contain mercury which causes cancer in rats and growth problems in babies of exposed women. But no definite evidence exists of linking mercury exposure in humans to cancer.

The greens and blues contain cobalt, which has been found to cause cancers in animals - however, the risk in humans needs to be explored further.

One component of black ink, benzo(a)pyrene, is a potent cancer-causing chemical and has been linked to skin cancers in petroleum workers.

Last year, Jorgen Serup, Professor of Dermatology from Copenhagen University, reported that 13 of 21 tattoo inks commonly used in Europe contained cancer-causing chemicals. Even the tattoo ink manufacturers admit that 5% of their products contain these types of chemicals.

How much is too much?

But even if these inks do contain components which have the potential to cause cancer, we still don’t know whether people who have tattoos are exposed to enough of them to actually cause cancer.

It may be that very large doses are needed, well beyond the exposure from tattooing, or perhaps only small doses are required over time. This is an important fact which needs further research before the link between tattooing and cancer can be confirmed.

Tattoo dyes are injected into the deeper layer of the skin. Image from

The other issue is the nanoparticles.

There is nothing inherently dangerous about particles being tiny. While some people are concerned that nanoparticles in sunscreens could more easily pass through tissues into the blood stream, the available evidence shows they pose no risk.

Tattoo dyes, of course, are injected into the deeper layer of the skin. The issue here is less about the nanoparticle make-up and more about exposure to cancer-causing chemicals. But we still don’t know whether enough chemical gets into the body to cause harm.

Further evidence could easily be collected by observing if people with tattoos have more cancers than those without. The problem here is that developing cancer is a process that often takes decades, so sufficient time between the tattoo and the recording of the cancer must be allowed.

During that time, people will have been exposed to multiple cancer causing agents in the environment. And, unless the association between cancer and tattoos is very strong, it may be difficult to tease out the tattoo as the cause of the cancer.

One review of the available literature found reports of 50 skin cancers in tattoos. The authors believed that was low compared to the number of tattoos (it has been estimated that one in five people in the UK have a tattoo) and thought it was coincidental, rather than the tattoo causing the cancer.

Tattoos may, however, make it difficult to detect skin cancers early and the tattoo may be obscured after surgery.

How should we respond?

It’s important for regulators, often of the cosmetics industry under which these products commonly fall, to be aware of the chemicals that increase the risk of cancer. And it would prudent for manufacturers to remove these chemicals from the inks, particularly as they claim that they make up such a small percentage of the products.

If you’re contemplating getting a tattoo, it’s worth asking about the chemicals in the inks and avoiding those with the potential to cause cancer, if that’s possible, even though the link with cancer needs further research.

But like all of the other major lifestyle risk factors for cancer – smoking, obesity, alcohol and sun protection – individuals must weigh the risk and benefit for themselves, a decision often influenced by the dictates of fashion.

Further reading:

Invisible ink: the rise of the tattoo removal industry

Explainer: how are tattoos removed?

Join the conversation

5 Comments sorted by

  1. Will Hunt


    When I was a kid you paid your 2/- (thats 2 shillings, kiddies) to the man who ran the tent at the Adelaide Show, and you could go in and see the tattooed Lady. At another tent, for another 2 shillings you could see the Fat Lady.
    These days, you can walk down the street and see the tattooed fat lady for Nothing.
    Who said there is no such thing as progress?
    Lucky Us.

    1. Sue Ieraci

      Public hospital clinician

      In reply to Will Hunt

      So, if both tattoo ink and obesity increase the risk of cancer, I wonder of those poor women are still around...

  2. Louise Sales

    logged in via LinkedIn

    Ian Olver’s conclusion that nanoparticles in sunscreen pose no risk is not shared by the European Commissions Scientific Committee on Consumer Safety (SCCS). The SCCS recently recommended that certain nano titanium dioxide (TiO2) ingredients not be used in sunscreen because they strongly react with sunlight to produce free radicals. The SCCS also recommended that nano TiO2 and nano zinc oxide (ZnO) not be used in powder or sprayable products because of the toxicity risk associated with inhalation…

    Read more
  3. Chris Strudwick


    Not being an expert on tattoo ink chemistry, my assumption would be that inks are chosen to be stable over long periods and are anyway present in very small quantities relative to a likely recipient's body mass. My concern is that tattoo removal, which fragments the ink into very fine particles so they can be removed by immune processes, could make the situation worse by greatly increasing the surface area and mobility of the particles and possibly making them more reactive as the chemistry moves into the nano scale.

    1. Louise Sales

      Friends of the Earth Nanotechnology Project

      In reply to Chris Strudwick

      Indeed Chris. If you have a tattoo you are probably best to leave it well alone. Lasers are often used to remove tattoos which shatter the pigments, making the particles unstable and more likely to flow into the body’s lymph system, and - if they are small enough - into the blood stream. Scientists are concerned that if these settle in an area, the harm could build slowly and only declare itself decades later, perhaps in the form of a cancer.