A university researcher says he’s developing a tattoo removal cream that could remove tattoos cheaply and without pain.

A tattoo doesn’t work simply by burying ink deep enough  (in the dermis) that it remains in place as the skin regenerates. Instead it’s that the needle doesn’t just deliver the pigment, but rather that its penetration causes the body’s immune system to send protective cells known as macrophages to the wound. These macrophages soak up the pigment to protect the rest of the skin and, while some macrophages are carried to the lymph nodes, others stay lodged in place, with the dye remaining visible through the skin.

At the moment, most tattoo removal involves using lasers to break down the ink particles so that they are small enough to be absorbed into the body. In effect it’s an attempt to speed up a natural process by which tattoos fade over time because of exposure to sunlight (just not quickly enough for the tattoo to disappear during an average lifespan.) That can mean painful inflammation and even scarring.

Alec Falkenham, a PhD student at Dalhouse University in Halifax, Nova Scotia, has developed what he calls Bisphosphonate Liposomal Tattoo Removal cream. Although it doesn’t require puncturing the skin, it simulates the introduction of a foreign body that comes with tattooing. The idea is that this stimulates the body to deliver fresh macrophages, with the existing ones (containing the pigment) carried to the lymph nodes.

At the moment Falkenham has only tested the cream on mice. He’s looking to move to pigs next before eventual human tests. The estimated price of the cream would be just four and a half cents per square centimetre, though Falkenham isn’t yet sure how many treatments would be needed in humans.

Falkenham has four tattoos and, although perfectly happy with them, says the experience of getting them started him thinking about the relationship between tattooing and the immune system.