Surprisingly little is known about the long-term health effects of tattooing, which has become a global trend in recent decades. Tattoos are often considered an artistic form of self-expression, but from a scientific perspective, tattooing can be defined as the intradermal injection of poorly soluble inorganic and/or organic colour pigments diluted in a carrier liquid. Despite attempts to control the ingredients used in the manufacture of inks at the national and international level, the resulting chemical mixtures often have hazardous toxicological profiles and may contain substances classified by the IARC Monographs programme as carcinogenic (Group 1), probably carcinogenic (Group 2A), or possibly carcinogenic (Group 2B) to humans upon dermal and respiratory exposure. Because most of the pigment particles, which are often nanoparticle-sized, will eventually be transported from the dermis to adjacent draining lymph nodes, exposure to tattoo ink may be systemic rather than locally confined. Therefore, potential systemic health effects of tattoos are not limited to the dermis but could include various types of lymphoma, as well as cancers of the kidney, bladder, and liver.

This website presents the latest research stream from the Environment and Lifestyle Epidemiology Branch at IARC on the potential long-term health effects of tattooing.