Could tattoos actually give you disease? honestly, science doesn't know

We all know that tattoos are permanent. We also know that if you want a tattoo, it’s usually a good idea to visit a reputable parlor that sterilizes clean, fresh needles, so theres no risk for disease.

But here’s what we don't know about tattoos: What happens to the ink when it enters your body?

Even though the practice of tattooing is thousands of years old, science hasn't actually figured out how tattoos work on a biochemical level. A study from researchers at the European Synchotron Radiation Facility in France explored what happens to ink after it enters your skin — and came up with more questions than answers.

The ink that’s injected into the skin during a tattoo sesh unleashes the body’s immune system to attack what it sees as a foreign invader. That’s where lymph nodes — kidney bean-shaped glands scattered throughout the body containing disease-fighting lymphocytes and white blood cells — come into the picture.

As the study authors point out, lymph nodes actually get tinted with the pigments in a tattoo soon after a session, which is normal: Your body is just reacting to a foreign element in your system and wants to get rid of it.

But the team of scientists wanted to figure out how lymph nodes react to tattoo ink. So they compared the tattooed skin of four donor corpses with the non-tatted skin of two other cadavers using x-ray fluorescence.

The x-ray was meant to study how ink traveled from tattoos to neighboring lymph nodes, and what remnants, if any, remained.

The research team found that the tattooed bodies had higher levels of titanium dioxide, a major ingredient in tattoo pigments, in their skin and lymph nodes. That makes sense. But what they also found were infinitesimally tinier particles of titanium dioxide measuring in the nanometers — that's about a billionth of a meter — deep within the lymph nodes.

That’s potentially worrisome. Titanium dioxide is a common chemical used in paints, cosmetics, sunscreen, and even foods. White pigmentation in commercial products is common, and titanium dioxide is a mainstay in this arena. In small doses, it's not been shown to affect humans. But a 2006 study by WHO's International Agency for Research on Cancer showed that heavier doses in rats caused fatal lung cancers. The report was careful to note that while the human link wasn't established, it was cause for concern.

Until this study, scientists had no idea how pushing these chemicals through skin and into bloodstream worked. But the nanoparticles from tattoo ink holing up in lymph nodes could be problematic for those with multiple tattoos — the more tattoos you get, the more ink you're putting in your system, the more nanoparticles are lodging themselves within your lymph nodes.

But that doesn’t mean every tattooed person has inadvertently signed up for cancer. Because scientists are still unsure how nanoparticles work, they might get swiped up by lymphocytes and hauled off to protect your immune system ... or they might be chilling in your lymph nodes and building up a store of carcinogens. The Daily Mail went so far as to suggest that the combination of chemicals could cause cancer.

That's not quite true, given we don't exactly know how nanoparticles move or if nanoparticles of carcinogens are harmful. Most importantly, the study involved six dead bodies, which is a small sample; it’s also impossible to judge the immune system of a corpse because, well, they’re dead.

But should a tattoo be in your future, the authors note that it's worth investing as much time in understanding the chemical compounds of your tattoo — and that's just as important as going to a clean, reputable place to get inked.