Tattoo ink pigments can migrate throughout the body, accumulate in lymph nodes, and have long-term effects on the immune system, according to new research reported by The Conversation.

Tattoo inks are complex chemical mixtures consisting of pigments, solvents, additives, and often traces of heavy metals such as nickel, chromium, cobalt, and lead. Many of these substances were originally developed for industrial use rather than for introduction into the human body. Once injected under the skin, immune cells attempt to remove the pigment particles but are unable to do so—this is why tattoos remain permanent. Some particles, however, migrate through the lymphatic system.

Studies show that these pigments can trigger long-term inflammation. An unexpected effect has also been identified: the presence of tattoo ink at a vaccination site may weaken the immune response to the vaccine.

Another concern is the composition of the dyes. Azo dyes, for example, can break down under ultraviolet light or during laser removal, forming potentially carcinogenic compounds. Black pigments often contain substances similar to those found in soot and exhaust emissions.

Experts emphasize that for most people, tattoos do not lead to serious health consequences. However, they cannot be considered completely safe. Scientists are calling for stricter regulation and control over the composition of tattoo inks.