Where does tattoo ink go in your body? There’s one particular spot.

Tattoos are no longer taboo. One in every three Americans now has at least one tattoo. As getting inked becomes more common, potential risks and side effects are being more intensely scrutinized. Last year, a series of worrisome headlines suggested a link between tattoos and lymphoma. These scare stories were based on a study of 1,400 people with lymphoma and a control group of over 4,000 people without cancer. 

This study’s authors claimed that their study showed that getting a tattoo increased risk, but their data actually suggested that any differences were not statistically significant. If tattoo ink did cause cancer, you’d expect people who had more of their body tattooed to be at greater risk. Crucially, the authors did not find this. Even if the data were more convincing, the study’s format makes it impossible to tell whether any link is causal–there could be factors that make people more likely to get lymphoma and tattoos. 

These health risks were overblown, but the study got me thinking about tattoo ink–where does it go in our skin, and does it stay there?  

Where does tattoo ink go in our skin?

When we get tattooed, the ink is deposited as a pigment in the dermis of our skin, explains dermatologist Dr. Lauren Ploch. This is below the top layer of skin–the epidermis–but above the skin’s fat. Cells in the dermis are replaced much more slowly than in the epidermis, which is why tattoos don’t fade as we shed skin cells. Your first consideration before getting a tattoo should be needle hygiene. Unclean needles spread infection and disease. 

When tattoo ink enters your skin, your body recognizes it as foreign, says dermatologist Dr. Lauren Moy. That causes the body to recruit immune cells to the area. This is why newly tattooed skin can become inflamed or sensitive. In most cases, careful after-tattoo care can mitigate most of these reactions. This includes keeping the tattooed skin area clean, using moisturizer, and avoiding exposure to sun or water. 

The immune cells that flood into your newly tattooed skin include macrophages–specialists in munching foreign molecules. These cells devour the pigment but struggle to break it down. This means the ink in our tattoos is distributed between skin and immune cells. When macrophages die, they release their contents, but that ink is rapidly eaten by other macrophages in the area. This “capture” and “recapture” process holds ink in place in the skin. 

But if your body has an allergic reaction to the ink, a red or pink thick, scaly area can form on your skin, says Ploch. Some of these allergic reactions are caused by immune cells called lymphocytes. Certain types of ink are more likely to provoke these pseudolymphomatous reactions. One study of 104 skin biopsies from people who had allergic reactions to their tattoos showed that 78 percent of the reactions involved red pigments. These responses can also occur months or years after the tattoo was inked. 

Can tattoo ink move out of the skin?

“Tattoo ink can technically move through the body, but it does not usually travel very far,” explains Ploch. When ink does move, it’s because the immune system has broken the pigment down to a size where it can be fed into our lymphatic system, which drains into lymph nodes. This pigment breakdown contributes to the blurring or fading of the tattoo. Nevertheless, even pigment that has been smashed to bits by the immune system and shuttled out of the skin can still cause issues. 

A 2018 case study reported the case of a heavily tattooed cancer patient whose mastectomy went in an unexpected direction when her surgeons noted her lymph nodes had turned black. An incorrect diagnosis could have led to the woman being treated for malignant melanoma. Luckily, her doctors realized the color was caused by broken-down tattoo ink building up in the nodes. Their analysis showed the discoloration wasn’t dangerous. 

A link to our ink? 

Pigment breakdown also happens when tattoos are removed. “Most lasers on the market now essentially break apart the pigment into smaller pieces so that it can be cleared by our lymphatic system quickly and more efficiently,” says Ploch. This process, says Moy, releases chemicals like iron and zinc oxides from the pigment, which can cause further reactions.  

Ultimately, though, these reactions are generally mild, says Ploch. As for any cancer risk, Moy points out that any link between tattoos and cancer would have been noticed in our increasingly inked world. “I think if tattoos were really that dire, we all would have heard about it,” she concludes.

This story is part of Popular Science’s Ask Us Anything series, where we answer your most outlandish, mind-burning questions, from the ordinary to the off-the-wall. Have something you’ve always wanted to know? Ask us.

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