Updated | There are many factors to think about when deciding to get a tattoo. When choosing a tattoo artist and parlor, safety and cleanliness rank top priority to prevent infections from dirty needles. A recent study published in Scientific Reports suggests tattoo aficionados should also take a closer look at the ink.
Tattoo ink is made up of various organic and inorganic pigments, which can be tainted with toxic element impurities. Researchers from Germany and France wanted to know whether, and how, this material affects the body.
The team looked to dead bodies to find out. As Gizmodo reports, the researchers collected tissue samples from six people who had donated their bodies to science upon death. Four of the bodies had tattoos and two did not. Two of the four inked corpses had ink in their lymph nodes. Aluminum, chromium, iron, nickel, copper and titanium were also present in heightened amounts in the tattooed bodies.
Using a high-tech X-ray light, the researchers found lymph nodes tinted with the color of the tattoo. They also found nanoparticles of toxic elements from tattoo pigment. The average size of these particles was 180 nanometers (to put this in perspective, a human hair is around 75,000 nanometers wide).
Finding lymph nodes colored with the tattoo ink was not surprising. Lymph nodes—located in the head and neck region, armpits and groin area—help clean the site where the tattoo needle entered. But finding pigment in nano form was unexpected. This size "implies that they may not have the same behavior as the particles at a micro level," Bernhard Hesse, co-lead author of the study and a visiting scientist at the European Synchrotron Radiation Facility in France, said in the statement. "And that is the problem: we don’t know how nanoparticles react." And because the samples were from dead bodies that had been tattooed not immediately before death, the researchers inferred that the nanoparticles had lingered in the lymph nodes for a while.
As for the elevated levels of titanium found in all the inked-up bodies, that likely came from titanium dioxide, the second-most common ingredient in tattoo inks. This white pigment is used to create certain shades when mixed with colorants. The compound is also used in food additives, sunscreens and paints, all of which could theoretically contribute to the elevated body levels. But as the researchers note, prior work has shown that respiratory exposure to titanium dioxide leaves the element only in the lung and hilar lymph nodes. In these bodies, the nanoparticles were not confined to those specific regions, suggesting the effects of tattoos are more than skin deep.
There's also a concern that the black pigment in tattoo ink may contain nanoparticles that are carcinogenic. A study in the British Journal of Dermatology found some nanoparticles may cause toxic effects in the brain and nerve damage. This finding suggests ink particles are capable of leaving the surface of the skin and traveling throughout the body, possibly entering organs and other tissues.
There's still a lot to be learned about how these pigments interact with the body, but clearly there's good reason to think before you ink.
This article has been updated to add attribution