Kymberlie Dozois Photography/Getty Images Scientists at Binghamton University (State University of New York) analyzed nearly 100 different tattoo inks and found that manufacturers’ ingredient labels (when used) are often inaccurate and that many inks contain small nanoscale particles that could be harmful to human cells. They presented their findings at this week’s meeting of the American Chemical Society (ACS) in Chicago. According to lead researcher John Swierk, a chemist in Binghamton, the project first began when his team became interested in tattoos as medical diagnostic tools. This shifted to an interest in laser tattoo removal, specifically how laser light causes tattoos to fade. “We realized that we didn’t understand much about the interaction between light and tattooing,” Swierk said during a press briefing at the ACS meeting. “My group studies how light can cause chemical reactions, so it was a natural application.” This meant learning more about the chemical makeup of tattoo inks, which is also not well understood. One reason for this significant gap in scientific understanding is that, at least in the US, tattoo ink manufacturers are not required to disclose ingredients, and even when they do, there is no real oversight of whether those disclosures are correct, per Swierk. Typical tattoo ink contains one or more pigments (which give the ink its color) inside a “carrier package” to help deliver the pigments to the skin. Pigments are the same as those used in paints and fabrics. They can be either small pieces of solids or discrete molecules, such as titanium dioxide or iron oxide (for white or rust-brown colors, respectively). When it comes to transfer packs, most ink makers use grain or rubbing alcohol, sometimes adding a bit of witch hazel to the mix to help the skin heal after the tattooing process. Other additives may also be present to adjust viscosity and maintain suspended pigment particles in the carrier package. Advertisement Enlarge / The European Union has recently cracked down on blue and green pigments used in tattoo inks. justtscott/Getty Images First, the team interviewed several tattoo artists and found that while the artists had their preferred brands, they knew very little about the chemical composition of their favorite inks. Swierk’s lab then used various methods to analyze a wide range of tattoo inks, including Raman spectroscopy, nuclear magnetic resonance spectroscopy, and electron microscopy. This allowed them to identify specific pigments and other ingredients in the various inks. They found that several ingredients did not appear on manufacturers’ labels, such as an ink that contained ethanol, even though it was not listed on the label. And 23 of the inks analyzed so far show evidence of an azo-containing pigment. Such pigments are usually inert, but exposure to bacteria or UV light can cause them to break down into a nitrogen-based compound that could potentially cause cancer. Additionally, says Swierk, “Often the particle sizes used in tattoo inks are very small—less than 100 nanometers in diameter. When you get to that size regime, you start to have concerns about nanoparticles penetrating cells, entering into the core and causing damage, possibly causing cancer.” About half of the 18 inks analyzed by electron microscopy had particles in this alarming size range. Enlarge / Colored ink bottles mixed in a box at a tattoo parlor in Berlin. John MacDougall/AFP/Getty Images The European Commission recently began cracking down on harmful chemicals in tattoo ink, including two widely used blue and green pigments (Pigment Blue 15 and Pigment Green 7), arguing that they are often of low purity and may contain dangerous substances. “Anyone tattooing in the US with blue or green tattoo inks should assume that these worrisome pigments will be included,” Swierk said. “Most tattoo manufacturers stop selling blue and green inks in Europe [in response to the regulatory crackdown]not necessarily a color change, because there’s no obvious replacement right now.” Advertising
However, he added that while the EU’s scientific data is worrying, it is not yet conclusive on the overall safety of the colourants. “These particular pigments have been used in tattooing for a long time,” Swierk said. “As with anything related to tattooing, it’s up to consumers to make a decision about their specific comfort level and then proceed accordingly.” That’s why Swierk and his team created a new website, What’s in My Ink? Their research will ultimately be the first comprehensive survey of tattoo inks in the US market, according to Swierk. Currently only rudimentary data from previous peer-reviewed studies are available, but once his team completes its analysis of commercial tattoo inks and the resulting data goes through the peer-review process, the site will serve as a valuable resource consumers for information on the composition of tattoo inks. The science and chemistry at play on our skin reacts with tattoo ink.