INJECTING RANDOM SUBSTANCES INTO YOUR BODY MIGHT HAVE CONSEQUENCES? GO FIGURE. Tattoos Affect Your Immune System in Ways We’re Only Beginning to Understand. “Tattoos are generally considered safe, but growing scientific evidence suggests tattoo inks are not biologically inert. The key question is no longer whether tattoos introduce foreign substances into the body, but how toxic those substances might be and what that means for long-term health.”

Given how many tatted-up people are walking around, any impacts must be minor, subtle, or long-term.