01 July 2024

90% of tattoo ink has undeclared hazardous substances in it

When getting a tattoo, do you know what exactly is being injected under your skin? American scientists have found out that in most cases the list of ingredients of tattoo ink does not coincide with the actual composition, and some components can threaten health.

The study, which was recently published in the journal Analytical Chemistry, was conducted by specialists from the chemical laboratory of Binghamton University (New York State, USA) under the guidance of Associate Professor of Chemistry John Swierk (John Swierk).

This is not their first work on tattoo inks. For example, earlier scientists from this team found in the ink not specified on the labels of nitrogen-containing dyes. Although they are considered safe, and some types are even used in the food industry, under the influence of ultraviolet light or bacteria such pigments can break down to nitrogen-containing compounds known as potential carcinogens.

This time the chemists analysed 54 varieties of tattoo ink in six colours and compared their declared and actual compositions. The study looked at products from nine manufacturers in the US, including large international companies and small brands.

Using methods of nuclear magnetic resonance, Raman spectroscopy, mass spectrometry and X-ray fluorescence analysis, the scientists found that 45 inks out of 54, that is, 90%, the composition on the label did not match what was actually. For example, the inks contained pigments other than the components listed. They also contained unspecified additives.

More than half of the inks contained polyethylene glycol not declared in the composition, which can damage internal organs with repeated exposure. In 15 inks scientists found propylene glycol, which is classified as a potential allergen. Also among the foreign substances were antibiotic hexamethylenetetramine, commonly used in urinary tract infections, and preservative 2-phenoxyethanol, dangerous for breastfed babies if ingested in breast milk.

However, researchers have not been able to determine whether manufacturers added these ingredients intentionally, or whether they got into the ink as a result of mislabelling or contamination of the ingredients used to make it.

Among the most common adverse effects of tattooing, the authors cited allergic reactions. Such side effects can be not only persistent and painful, but also disfiguring. Red pigments are considered particularly problematic, although scientists don't fully know why exactly.

Researchers said they are continuing to work on the safety of tattoos and their health effects.

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