Studies are finding that tattoo ink can end up in your lymph nodes.

Here’s a look at what happens to tattoo ink after it gets injected into your skin and the risks associated with a certain type of tattoo ink.

Tattoos are permanent works of art on your skin. But the ink doesn’t always stay where you can see it. When you get a tattoo, your skin gets punctured with hundreds of needle pricks. Each prick deposits ink into the dermis, which is the layer of skin below the epidermis. The dermis houses blood vessels and nerves.

But a study in Scientific Report suggests that some of the ink migrates through the lymphatic system. It then gets carried to the lymph nodes, whose job it is to filter out harmful substances from the body. The lymphatic system and lymph nodes are things that you don’t want to mess with in your body. They are vital to the immune system, fight cancer and carry lymph fluid directly to the heart. Sending tattoo ink to your heart sure sounds like a bad idea. The evidence that proves this was done through conducting analyses on cadavers with tattoos that have shown enlarged and pigmented lymph nodes.

But what’s in the ink exactly?

Black tattoos in particular are commonly made of iron oxide and carbon. While colored ink may contain nickel, chromium, manganese, or cobalt, which means that tiny particles of these metals are ending up in your lymph nodes. While these are all items to be concerned about, titanium dioxide in particular is highlighted in the report as the substance to most watch out for.

It appears that titanium dioxide is the thing that is infecting the lymph nodes. Unfortunately, titanium dioxide is the second most common substance used for tattoo dyeing, meaning infections could be widespread.

Meanwhile, research on mice found that tattoo ink travels through the blood system to the liver. This shows that there is a strong chance that in humans tattoo ink can reach organs via the lymphatic system.

But is it harmful?

Longitudinal studies need to be conducted in order to understand the long term effects on tattoo ink and titanium dioxide in particular. Until then, you may want to ask your tattoo artist if the ink contains titanium dioxide particles. It may sound like an odd question at the time, but it could be very important. If you need more information on identifying it, remember that it is referred to as titanium white, Pigment White 6 (PW6) or CI 77891.

Some news sources are running with the idea that tattoo ink is the next tobacco. For example, the Daily Mail interpreted the Scientific Report article’s findings as an indication that tattoos could give you cancer. Yes, this is alarming but is definitely clutching at straws; it’s drawn on the knowledge that lymph nodes catch cancer cells as they’re metastasizing around the body, destroying them. It’s known that when lymph nodes do not destroy the cancer cells, they can become an area where more cancerous tumors grow. Stating tattoo ink can cause cancer by tampering with this method is not proved at all. While the Daily Mail article is definitely a hyperbolic interpretation, it has picked up on some genuine concerns that need to be addressed. For example, it correctly addresses the point that if the ink is damaging the lymph nodes, then the immune system is infected, so it’s a very real prospect that affected people are less able to fight off infections than they would have been.

While the evidence is inconclusive, it’s certainly a good idea to err on the side of caution. Web MD states right at the top of its article on the subject that those seeking a tattoo should be very careful when choosing where they go. That means that the tattoo you got on a drunken night out could be harmful as well as regrettable.