Unlisted ingredients found in tattoo inks

In a new study analyzing 54 tattoo inks sold in the US, researchers found that 45 contained pigments or additives that manufacturers did not list on the ingredient label ( Anal. Chem. 2024, DOI: 10.1021/acs.analchem.3c05687 ). The unlisted compounds include propylene glycol, polyethylene glycol, and 2-phenoxyethanol—ingredients that could cause allergic reactions or other adverse health effects. John Swierk, one of the study's authors and a chemistry professor at Binghamton University, says the findings suggest an issue with labeling accuracy across the US tattoo ink market. The discrepancies could pose a safety issue for some people who get tattoos. "If there are unlisted things in there and people are having problems, it makes it harder to understand where those problems may be coming from," he says. Tattoo inks in their simplest form are pigments suspended in a carrier package typically made of alcohol and water. Inks can also contain additives like