Decoding Tattoo Inks: Multiple Analysis Techniques Reveal Discrepancies in Ingredient Composition and Elemental Content When Compared Against Label Claims

Permanent body art has grown in popularity in recent years, with millions of individuals having black/monochrome or colorful tattoos. With this decision to get a tattoo comes risk: Injecting coloring compounds into the skin has been reported to cause allergies, skin inflammation, and systemic disorders. Despite the growing number of tattooed individuals, there are currently few regulations, laws, and safety criteria for tattoo and permanent cosmetic formulations. The goal of our study was to identify the pigments in a set of commercially available yellow tattoo inks. We examined a set of previously unstudied yellow tattoo inks: lemon yellow (LY), golden yellow (GY), golden rod (GR), and bright orange (BO). We also examined reference pigments: pigment yellow 14 (PY14), pigment yellow 65 (PY65), pigment blue 15 (PB15), and pigment orange 13 (PO13). Both sets of inks were examined using a range of techniques, including Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, X-ray diffraction (XRD), Raman spectroscopy, energy dispersive X-ray (EDX) spectroscopy, and inductively coupled plasma optical emission spectroscopy (ICP-OES). We report that the combined use of these techniques can provide major insights into ink composition without needing difficult and time-consuming sample preparation. Results of our study indicate that the ink compositions differed from what was described on the labels. Furthermore, we demonstrate that the tattoo inks tested included additional elements that were not listed as ingredients, such as aluminum (Al), sodium (Na), and silicon (Si). These unlabeled ingredients raise concerns about the regulation, health effects, and degradation products of tattoo inks.