You’ve probably seen tattoo studios popping up everywhere, and the numbers back that up. About 30% of Americans have at least one tattoo, and among adults aged 18 to 34, that number climbs to 40%. Tattoos aren’t fringe anymore. They’re as common as a cup of coffee. But recent science is asking a question worth your time: Do we really know what’s in that ink being pushed into your skin?

The answer, it turns out, isn’t reassuring.

The Label Isn’t the Whole Story

Researchers at a major university examined 54 inks from nine well-known tattoo brands sold in the United States. What they found should give anyone pause. Of the 54 inks, 45 contained ingredients not listed on their labels. Only the inks from one brand showed complete agreement between what was listed and what was actually inside the bottle.

The most common unlisted ingredient was polyethylene glycol, or PEG, which appeared in more than half of the inks tested. This substance can affect the kidneys over time, and scientists have flagged it as something that may cause organ damage with repeated exposure. Propylene glycol turned up in 15 of the 54 inks. It was named the American Contact Dermatitis Society’s Allergen of the Year in 2018, meaning it’s a well-known trigger for rashes, swelling, and blisters.

The pigments told an equally troubling story. Some brands listed pigments on their packaging that simply weren’t there when scientists tested them. Others contained pigments that weren’t listed at all. Six inks with the biggest gaps between label and reality came from the same brand, which listed ingredients on every bottle that were absent from all its products.

Heavy metals hiding in tattoo inks add another layer of concern. Research has identified cadmium, lead, mercury, and arsenic as contaminants found in various tattoo products, and these metals have been linked to cancer, brain disease, and problems with the heart and hormones. Some of the pigments found in US inks, particularly the red and yellow ones, fall into a category of chemicals that can release substances known or suspected to cause cancer when they’re exposed to sunlight or broken down by laser treatment.

What the Cancer Research Is Saying

Two significant studies published in 2024 and 2025 brought cancer concerns into sharper focus. A large population-based study out of Sweden tracked more than 11,000 people and found that those with tattoos had a 21% higher risk of developing malignant lymphoma, which is a cancer of the immune system. The risk appeared to increase for people who’d had their tattoos for 11 or more years, suggesting that long-term exposure to ink particles matters.

That same Swedish study turned up something striking about laser tattoo removal. People who had their tattoos removed by laser showed a risk of lymphoma nearly three times higher than non-tattooed individuals. Scientists suspect the process of breaking ink down with lasers releases harmful chemicals that then travel through the body in unpredictable ways.

A Danish twin study published in early 2025 approached the question from a different angle, comparing twins in which one had tattoos and the other didn’t. It found that tattooed individuals had a 62% higher risk of skin cancer and that people with tattoos covering an area larger than the palm of one hand risked lymphoma nearly three times greater than their non-tattooed counterparts. The twin design is particularly useful because it controls for factors that are difficult to measure in other studies, like shared genetics and upbringing.

It’s worth being honest about what these studies do and don’t tell us. They found associations, meaning that tattooed people were more likely to develop certain cancers. They didn’t prove that the ink directly caused those cancers. Scientists call this distinction the difference between correlation and causation, and it matters. At least one newer study found no significant increased cancer risk in a different tattooed population, showing that the science is still being sorted out. Lifestyle factors, sun exposure, and behaviors that tend to go along with tattooing could all play a role that’s hard to separate from the ink itself.

Still, the researchers who conducted these studies are calling for more investigation, and that call is difficult to argue with given what they’ve found.

Where Does Regulation Stand?

Here’s the part that might surprise you most. The FDA classifies tattoo ink as a cosmetic product, which means it doesn’t approve tattoo inks before they reach the market and has historically had limited power to require recalls. That started to change in 2022 with a new federal law called the Modernization of Cosmetics Regulation Act, which expanded the FDA’s ability to address safety concerns, require adverse event reporting, and issue recalls.

In 2024, the FDA took another step by releasing final guidance on sanitary conditions for tattoo ink manufacturing. Between 2003 and 2024, there were 18 voluntary recalls of contaminated inks, with the most recent issued in August 2024. Some of those contaminated inks carried harmful bacteria that caused real illnesses in real people.

Voluntary recalls and guidance documents aren’t the same as strict, enforceable standards. Scientists and legal scholars who study this area have called for mandatory ingredient standards, limits for toxic substances, and required testing before any ink reaches the market. Right now, manufacturers largely decide for themselves what goes into their products and whether those products are safe.

If you have tattoos or you’re considering getting one, a few things are worth knowing. Asking your tattoo artist about the brands they use and whether those brands have independent testing is a reasonable question. Choosing a studio that can show you safety data sheets for its products is a good idea. So far, the research doesn’t say that everyone who gets tattooed will develop cancer. It says that questions about long-term safety deserve serious answers and that the industry needs better oversight to provide them.

The science of tattoo ink safety is still developing to keep pace with the popularity of tattoos. What’s clear is that millions of people are walking around with substances in their skin that weren’t fully disclosed on any label, and the health questions surrounding those substances are real enough to warrant both attention and action.