According to the European Commission's Joint Research Center (JRC), 12% of Europeans and as many as 24% of Americans have tattoos. Which makes this next fact all the more alarming: a lack of research and spotty regulation of tattoo inks means those tattoos could contain a whole host of harmful compounds. For example, many pigments in tattoo inks are sourced from the textile, plastic, or automotive industry.
A 2016 JRC report analyzed a wide variety of tattoo pigments for the chemicals within them and listed the ones of most concern. The most dangerous are known as polycyclic aromatic hydrocarbons (PAHs), a chemical group found in mostly black inks that contains carcinogens and can migrate from the skin to the lymph nodes. There are also azo pigments, which make up about 60% of the color ingredients in tattoo inks. Though azo pigments are safe when they first enter the skin, they can degrade over time into potentially cancer-causing compounds. A Swiss survey of 229 tattoo inks also found problematic preservatives. A quarter of the inks contained the skin irritant benzo-isothiazolinone, and 7% contained formaldehyde, a carcinogen. Tattoo inks can also contain harmful metals such as nickel, chromium, and cobalt. To avoid potentially risky pigments, tattoo customers should get to know their artist and ask about where their ink is sourced before they go under the needle.