We Now Know That When You Get a Tattoo, the Ink Doesn't Just Stay on the Outside of the Skin

Turns out there’s more to worry about than pain, potential infection and skin aging when getting a tattoo: Scientists say the inks can actually migrate to the lymph nodes.

Researchers in Europe examined four cadavers with tattoos and two without, and found that the tattooed bodies’ lymph nodes contained multiple colored pigments. Taking it a step further, the researchers then tattooed corpses with synchrotron X-ray fluorescence, which allowed them to not only confirm that tattoo ink can migrate through the lymphatic system, but cause the lymph nodes to become inflamed as well. The findings were published in Scientific Reports in 2017.

“In conjunction with tattoos, pigmented and enlarged lymph nodes have been noticed in tattooed individuals for decades,” the study states, but confirmation and further study was limited to tattooing animals, which was deemed to be unethical.

The ink found in the nodes included particles measuring a few millionths to a few billionths of a centimeter in diameter. They contained a variety of heavy metals such as nickel, chromium, manganese and cobalt, as well as titanium dioxide, a mineral typically used to make white pigment or to create lighter shades of other colors. As the study indicates, while we might see a tattoo as a simple cutaneous adornment, the body sees it as a severe injury.

“After the traumatic insertion of inks during the tattooing procedure,” write the study authors, “the body will excrete as many components as possible via the damaged epidermis.”

The lymphatic system is one of the most significant components of the immune system, comprising a vast network of vessels that flush cellular debris, waste and bacteria. Thus, it would make sense that the introduction of organic and inorganic inks and heavy metal particles would send it into overdrive.

The implications of the study’s findings are significant. Tattoos weren’t particularly common in the U.S. until the past few decades, but a Pew Research Center study in 2010 found that nearly 40 percent of millennials have at least one tattoo — a percentage that’s likely to be higher in 2018.

Further, at least one study has linked the accumulation of pigments in the lymph nodes — especially titanium dioxide — with cancer.

“When someone wants to get a tattoo, they are often very careful in choosing a parlour where they use sterile needles,” said Hiram Castillo, a researcher at the European Synchrotron Radiation Facility in Grenoble, France, and co-author of the cancer study. “No one checks the chemical composition of the colours, but our study shows that maybe they should.”

Other studies on whether or not the inks can cause cancer have been inconclusive, but the original study researchers admit there’s much more investigation to be done in order to declare tattoos definitively safe or unsafe.

“In future experiments, we will also look into the pigment and heavy metal burden of other, more distant internal organs and tissues in order to track any possible biodistribution of tattoo ink ingredients throughout the body,” write the authors.