Study Finds Surprising Amount of Tattoo Ink Contains Bacteria

A new study is highlighting some of the lesser-known risks involved with getting a tattoo , finding that a whopping 35 percent of tattoo ink sold in the United States is contaminated with bacteria. Researchers believe the evidence demonstrates a link between tattoo ink and human infections.

The study, which is the first of its kind, was published on Tuesday in the Applied and Environmental Microbiology science journal. In coming up with the findings, the research team tested 75 tattoo inks from 14 manufacturers to detect the presence of both aerobic and anaerobic bacteria. Of the 75 ink samples, researchers found 26 samples that were contaminated.

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"Our findings reveal that unopened and sealed tattoo inks can harbor anaerobic bacteria, known to thrive in low-oxygen environments like the dermal layer of the skin, alongside aerobic bacteria," the study's authors write. "This suggests that contaminated tattoo inks could be a source of infection from both types of bacteria."

Dr. Seong-Jae (Peter) Kim, Ph.D., an Arkansas-based U.S. Food and Drug Administration microbiologist who co-authored the study, noted in a press release that "the rising popularity of tattooing in recent years has coincided with an increase in tattoo-related complications or adverse reactions."

"It should be noted that microbial infections constitute just one aspect of these complications," Kim explained. "In addition to microbial infections, immunologic complications such as inflammatory reactions and allergic hypersensitivity, as well as toxic responses, represent a significant portion of these issues. In light of our study results, we want to emphasize the importance of continuously monitoring these products to ensure the microbial safety of tattoo inks."

The FDA does not currently approve any tattoo ink or permanent makeup for injection into the skin, as it considers those products to be cosmetic.

However, on its website the federal agency warns of potential health effects such as infections and serious illness from unclean tattoo tools, practices, or products; allergic reactions that can cause skin problems or rashes; and increased risks of sunburn, rashes, redness, or scarring.

But bacteria isn't the only potential risk associated with getting inked. Another recent study found that the majority of tattoo inks sold in the U.S. have unlisted additives and pigments that could pose significant health risks. Specifically, many inks were found to contain 2-phenoxyethanol, which can potentially cause toxic effects including damage to the kidneys, lungs, and nerves.

Yet, even with the associated risks, more than 100 million Americans have at least one tattoo, according to Pew Research .