Thinking about getting a tattoo? Here's what you should know
Studies show an association, not causation, between tattoo ink and certain cancers: experts
Tattooing services are regulated and largely considered safe, but there's a growing group of experts concerned over links between tattoo ink and allergic reactions, as well as potential associations between tattoos and certain kinds of cancer.
Current evidence largely shows associations — not causation — with cancer, but experts say people should be aware that tattoos do come with a small amount of risk, even if more research is needed to determine the severity of that risk.
What are the risks of getting a tattoo?
Tattoos are permanent because they're formed when a needle containing ink pierces skin and deposits the pigment in the dermis — the skin's middle layer — according to Dalhousie University dermatologist Dr. Kerri Purdy.
The needle being dipped into ink and then penetrating the skin increases the risk of certain infections — like mycobacterial infections — as well as introduces the possibility of spreading diseases like hepatitis and HIV.
"That said, the risk is exceedingly low, with people and tattoo parlours being very careful about that," said Purdy, division head of clinical dermatology and cutaneous science at Dalhousie's school of medicine.
A 2025 two-part series on tattoo-associated infections published in the Lancet Microbe found that the risk of infection ranged from study to study.
In general, roughly one to six per cent of tattooed people experienced a microbial infection after receiving a tattoo, though it's not uncommon for people to experience minor skin elevation or itchiness after a fresh tattoo.
Tattoo infections are often mild to moderate, with the second paper in the two-part series explaining that tattooing can lead to life-threatening infections in "rare and extreme cases."
Purdy says people can develop allergic reactions to compounds present in the ink itself, once the ink makes it into our skin.
Western University chemist Yolanda Hedberg's 2021 study analyzed more than 70 tattoo ink samples, finding traces of potentially harmful metals like nickel and chromium in almost all of the samples tested.
Arsenic, mercury and lead all turned up in one sample each.
The study samples were collected both in-person and online from vendors in Sweden, but many of the ink samples were fabricated in the U.S. and are commonly available in many countries, including Canada.
The study found that 93 per cent of the inks tested violated European labelling requirements. Researchers concluded that 61 per cent of inks contained "pigments of concern," but found that the level of metal exceeded restriction limits in "only a few cases."
Hedberg added that the ingredients listed on an ink bottle didn't always match up with the actual ingredients in the ink itself.
Different tattoo inks also present different levels of risk, she says. For example, certain red inks contain azo dyes, increasing the allergic risk. Azo dyes are synthetic and do not occur naturally. Many are non-toxic, though some azo dyes are mutagens and carcinogens.
While tattoo allergies can develop within days of inking, Hedberg says it's not uncommon for tattoo allergies to develop after several weeks or even months, rather than immediately after inking.
The delay likely occurs because it takes time for the body to identify the tattoo as foreign material that needs to be removed. "Generally, you would notice an allergic reaction within three months," she said.
Mild cases of tattoo allergies can be treated using topical steroid creams.
More significant or swollen allergic reactions can be treated using corticosteroidal injections, while very severe reactions can require medications like prednisone, according to Purdy.
What does the research show about cancer?
A small number of studies have tracked a potential association between tattoos and the development of certain cancers, including melanoma and lymphoma.
A 2025 study of Danish twins found that the risk of skin cancer was 1.62 times higher among people with tattoos. The study looked at twins where one sibling had a tattoo and the other didn't, comparing the health of each twin.
The study sampled 2,367 randomly selected twins and a control group of 316 twins, all born between 1960 and 1996. The risk was determined for tattoos that were larger than the palm of a hand.
The study identified the lack of information on sun exposure as a possible limitation. Additionally, the study didn't look at factors like how many cigarettes were smoked by study participants.
Another study published in the Lancet in 2024 compared almost 1,400 people who had lymphoma to almost 4,200 people who didn't, finding that 21 per cent of the people with lymphoma had tattoos.
Nonetheless, the 2024 study found an association, not direct causation. The authors concluded that more research is needed to establish causality.
McGill University dermatologist Dr. Elena Netchiporouk says the core compound required to produce black ink — a compound known as carbon black — is a possible carcinogen derived in part from the incomplete combustion of petroleum products.
"We know that [carbon black] has very strong proof that it can cause cancer in humans," said Netchiporouk, speaking with The Dose's Dr. Brian Goldman.
Netchiporouk — who wasn't involved in the 2025 Danish study or the 2024 Lancet study — cautioned that current carcinogenic evidence comes from research on ingesting carbon black, not from injecting it into our skin.
She also said darker tattoos can also make it difficult to monitor for signs of skin cancer — especially if tattoos cover up moles.
It's not clear whether the size of someone's tattoos increase their cancer risk.
Netchiporouk says more research is necessary to determine the true cancer risk associated with tattoo inks.
What should I do if I'm worried?
Purdy recommends that anyone interested in getting a tattoo visit a reputable tattoo shop.
Tattoo parlours are regulated by provincial and territorial governments in Canada, while tattoo inks are subject to cosmetic regulations under the federal Food and Drugs Act.
"It is the responsibility of the manufacturer or importer to meet the requirements of the Food and Drugs Act and Cosmetic Regulations and ensure that the product they are selling is safe," Health Canada wrote in an email statement.
Still, Hedberg says Canada's tattoo regulations are less stringent than Europe's rules.
The EU banned in 2022 thousands of chemicals used in tattoo inks, which has affected certain blue and green pigments.
"In Canada, you can still tattoo all colours and they are not restricted here just yet," said Hedberg.
Netchiporouk says laser tattoo removal is usually a safe option.
However, she notes that the azo dyes typically present in red inks can undergo transformation because they're sensitive to ultraviolet radiation, as well as laser removal.
"They can transform into other chemicals in the skin, which can become more likely allergenic," said Netchiporouk.
Due to the questions surrounding tattoos, Netchiporouk isn't interested in getting one any time soon.
She says further research is required to determine the long-term risk of tattooing.
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