Tattooing has been a part of human culture for thousands of years, but only recently have scientists began more in-depth studies to determine the exact effects the practice may have on the human body. While there have been several cases of tattoos resulting in cancer-like symptoms, the most common side effects are symptoms similar to that of an allergic reaction.

As we all know, most of the ink that gets deposited in the skin becomes permanent, mainly because the ink particles are too large for the body to breakdown. But last year, scientists from the ESRF discovered that a very small amount of the ink does in fact get broken down by the immune system, and is subsequently spread throughout the body, which then ends up in lymph nodes. Some people may experience allergic reactions related to this process.

Most recently, scientists from the European Synchrotron Radiation Facility (ESRF) conducted a deeper study on the effects of tattooing on the human body. As a result of the study, researchers found that traces of nano-sized metals have somehow been left behind and were found in lymph nodes.

These metals found included nickel and chromium, which are allergens. Previous cases of infection, inflammation, and sensitivity around the tattooed area - common symptoms associated with what are assumed to be "botched" tattoos - were all considered to be linked to the pigments used, or to have occurred as a result of using unsanitary equipment.

"There is more to tattoos than meets the eye," said environmental scientist Hiram Castilla of the ESRF. "It is not only about the cleanliness of the parlor, the sterilization of the equipment or even about the pigments."

The nanoparticles discovered during the study appear to have been left behind by the needles used to puncture the skin and not necessarily the deposited ink.

"After studying several human tissue samples and finding metallic components, we realized that there must be something else," said Ines Schreiver of the German Federal Institute for Risk Assessment.

"We also tested around 50 ink samples without finding such metal particles and made sure that we hadn't contaminated the samples during sample preparation. Then we thought of testing the needle and that was our 'eureka' moment."

This discovery does not exonerate ink as a guilty party in the distribution of contaminates throughout the body. During the testing of various inks, scientists found titanium dioxide in a white pigment often used to brighten darker colored inks.

Come to find out, using these pigments actually increases the wear on tattoo needles, as titanium dioxide acts as an abrasive essentially shaving microscopic fragments from the needles every time they puncture the skin.

In tests using pig skin, researchers discovered that pigments using titanium dioxide exhibited much more wear than those using a softer, less abrasive, carbon black pigment.

"It is beyond doubt that the metal particles derive from the tattoo needle as result of more than just pure mechanical grinding," said Bernhard Hesse of the ESRF. 

It is imperative that before you decide to "get some work done" you do your homework. Choose a reputable studio, conduct medical checkups to determine any unknown allergies, and ask questions, find out what ingredients make up the ink. Essentially, protect yourself, as more research is required to determine the total effect that tattooing has on someone's health.