Tattoo ink may contain uncountable chemicals harmful to human health, says new study

Getting a tattoo is a symbol of self-expression and people have been decorating their bodies for decades for several different reasons. In today's day and age, tattoos are not only trendy but also considered a walking form of art. But little is known about the components used in the ink that goes inside our bodies.

A recent study suggests that half of the tattoo inks used in the United States contains chemicals that are harmful to human health.

The researchers, from State University of New York at Binghamton, analysed data from nearly 100 currently sold tattoo inks that contained chemicals not declared on their ingredients. The components, nanoparticle sizes, are suspected to be damaging to health.

The team also analysed 16 inks using electron microscopy, and about half contained particles smaller than 100 nm. “That’s a concerning size range,” said John Swierk, Ph.D., the project’s principal investigator. “Particles of this size can get through the cell membrane and potentially cause harm.”

The Science Behind Tattoo Ink
Tattoo inks contain two parts - a pigment and a carrier solution. The pigment could be a molecular compound; or a combination of the two compound types.

The carrier solution helps transport the pigment to the middle layer of skin and typically makes the pigment more soluble. It can also control the viscosity of the ink solution and sometimes includes an anti-inflammatory ingredient.

Swierk and undergraduates in his laboratory interviewed tattoo artists to see what they knew about the inks they use on their customers. While these artists identified a brand they preferred, they didn’t know much about the ink's contents.

It's important to note that tattoo artists must be licensed to work, yet no federal or local agency regulates the contents of the inks themselves.

The study confirmed the presence of ingredients that aren’t listed on some labels. For example, ethanol, which was not listed in one of such cases.

“Every time we looked at one of the inks, we found something that gave me pause,” Swierk says. “For example, 23 of 56 different inks analysed to date suggest an azo-containing dye is present.”

Although many azo pigments do not cause health concerns when they are chemically intact, bacteria or ultraviolet light can degrade them into another nitrogen-based compound that is a potential carcinogen, according to the Joint Research Centre, which provides independent scientific advice to the European Union.