It seems like everybody has a tattoo nowadays. Almost a third of people in the US have one and nearly half of millennials have at least one inking. Even the Prime Minister of Canada, Justin Trudeau, has one – so mainstream, man. 

Despite this booming popularity, scientists still know relatively little about the effect of tattoo ink on our body and health. 

A new study in the Nature journal Scientific Reports found that microscopic particles from tattoo ink can migrate into the body and wind up in the lymph nodes of your immune system.

“When someone wants to get a tattoo... no one checks the chemical composition of the colors, but our study shows that maybe they should,” explains Hiram Castillo, one of the authors of the study, in a statement.

Lymph nodes are part of the immune system and found throughout the body, including in the armpit, groin, and neck. They act a bit like a filter for foreign bodies, whether it's pathogens or cancer cells. Since the ink is a foreign body, this too gets swept up in this net.

Most tattoo inks contain organic pigments, however many include preservatives and contaminants like nickel, chromium, manganese, or cobalt. One of the most common ingredients in tattoo inks is the white pigment titanium dioxide (TiO2). We come across this inorganic chemical constantly in our everyday life, from food additives to sunscreens to paints. German and French scientists have now looked at how TiO2 degrades into toxic impurities and how these nanoparticles travel to the lymph nodes where they accumulate.

“We already knew that pigments from tattoos would travel to the lymph nodes because of visual evidence: the lymph nodes become tinted with the colour of the tattoo. It is the response of the body to clean the site of entrance of the tattoo,” added Bernhard Hesse, study first author. “What we didn't know is that they do it in a nano form, which implies that they may not have the same behavior as the particles at a micro level. And that is the problem: we don't know how nanoparticles react.”

It sounds scary but is this anything to worry about? Not yet, at least. You may have seen a few headlines saying: “Tattoos Give You Cancer, Study Suggests.” However, this link to the big-C was not in the scientific study and has not been mentioned by the researchers either.

That said, there's a potential risk to your health. Previous evidence suggests these toxic impurities could be associated with inflammation, however, once again, more research needs to be done before jumping to any hard conclusions.