Tattoo ink doesn’t just stay in the skin. New research shows it rushes into the lymphatic system, where it can persist for months, kill immune cells, and even disrupt how the body responds to different vaccines.

Scientists in Switzerland used a mouse model to trace what happens after tattooing. Pigments drained into nearby lymph nodes within minutes and continued to accumulate for two months, triggering immune-cell death and reshaping how the body responds to different vaccines.

In a recent study published in the Proceedings of the National Academy of Sciences, researchers investigated the journey of tattoo ink through the lymphatic system, as it accumulates in lymph nodes and affects immune cells, and examined its long-term effects on immune responses to vaccination.

They demonstrated that tattoo ink rapidly drains to lymph nodes, where macrophages take it up and often undergo cell death, triggering persistent inflammation for months. These effects were observed when vaccination occurred in the same lymphatic drainage area as the tattoo.

Ink accumulation reduced immunity to messenger ribonucleic acid (mRNA) vaccines for the coronavirus disease 2019 (COVID-19) when administered at the tattoo site, but enhanced responses to an influenza vaccine in an ink- and timing-dependent manner.

Tattooing has become highly prevalent worldwide, particularly among younger populations, with around 20 per cent of people globally and over 30 per cent in the United States having at least one tattoo.

The process introduces pigments deep into the layers of the skin through repeated needle penetration. Because these pigments are designed to be insoluble and long-lasting, they often contain complex mixtures of binders, solvents, and industrial colourants.

With billions spent on tattoos each year, the authors at Università della Svizzera Italiana in Bellinzona said the results point to a need for tougher toxicology testing and stricter oversight of tattoo-ink ingredients, which face far looser regulation than medical products.

The study doesn’t show whether similar immune effects occur in people — that hasn’t been tested. But it flags clear risks. Pigments have long been documented in human lymph nodes, and the mouse findings mirror what’s been observed in both humans and primates. (Nigerian Tribune)

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