Madalyn Wright

(CN) — Tattoo is an art form that has been around for centuries and carries rich cultural history. As the industry took off, the share of Americans with tattoos spiked from 9% to 30% in the last decade.

Unregulated by the FDA, the contents of tattoo ink — and their potential health risks — have been a mystery for years. While some people look into how to remove their exes’ names from their bodies with laser treatment, researchers at Binghamton University questioned what exactly is in tattoo ink.

“The idea for this project initially came about because I was interested in what happens when laser light is used to remove tattoos,” said John Swierk, the project’s principal investigator, in a press release. “But then I realized that very little is actually known about the composition of tattoo inks, so we started analyzing popular brands.”

When the researchers interviewed tattoo artists, the tattooists couldn’t explain their inks’ contents, but did know which brands they preferred.

“Surprisingly, no dye shop makes pigment specific for tattoo ink. Big companies manufacture pigments for everything, such as paint and textiles. These same pigments are used in tattoo inks,” Swierk said.

Tattoo ink always has two parts: a pigment for color and a carrier solution that brings the pigment to the middle layer of skin and can include an anti-inflammatory ingredient. Researchers used various techniques — such as Raman spectroscopy and electron microscopy — to analyze nearly 100 pigments’ particle size and molecular composition.

Then Swierk’s team confirmed that ingredients were present in the inks that were not listed on the label; one ink even contained ethanol, the active ingredient in alcoholic drinks. Approximately half of the 16 inks analyzed with electron microscopy included particles smaller than 100 nanometers, making them small enough to get through the cell membrane and potentially cause harm.

Other inks had azo-containing dye, which poses a cancer risk. Azo dyes contain a nitrogen group and can degrade into a potential carcinogen when degraded by bacteria or ultraviolet light.

“Every time we looked at one of the inks, we found something that gave me pause,” Swierk said.

Motivated by their findings and regard for the art form, the researchers crafted a website, What’s in My Ink?to keep artists and consumers informed on the contents and potential risks of different inks on the market. Swierk and his team presented their findings at the fall American Chemical Society meeting, which began Aug. 21 and will end Aug. 25.