For centuries we have assumed that once tattooed that’s it – the image or words are there for life. Then came tattoo cover-ups, allowing ink that people had grown tired of or grown out of to be covered up with a new design by experienced, talented artists.

Finally, we reached the point where lasers were employed to remove tattoos entirely. The technology works, and it means that those youthful (or not so youthful) indiscretions can be made as invisible as possible. Sometimes, however, it’s not possible to remove all of it. This is especially true of tattoos with a colored pigment.

Things may be about to change though. A study carried out in France, regarding just how permanent that ‘permanent’ ink from a tattoo is, has revealed surprising findings. The research, carried out on mice, has shown that the skin cells into which the tattoo is fixed are not fixed themselves, and when they die, those cells can pass the pigment on to new cells. But they don’t just pass them on – they ‘eat’ the tattoo beforehand, thus reducing the amount of ink in the skin over time.

Mouse tail showing the same tattoo before macrophages are killed. New macrophages moved in to abosrb the pigments, and the mouse retained its tattoo. CreditBaranska et al., 2018

These special cells are called macrophages and they are immune cells that you can find in the dermis (the true skin that is under the epidermis). It seems that they come swarming towards the site of the tattoo, thinking that it is a wound that needs to be healed (which, to all intents and purposes, it is). It consumes the ‘injured’ cells, thus replicating the tattoo for all eternity because when the macrophages die, they too are swallowed up. The tattoo remains the same, but the skin beneath it is different.

The authors speculate that laser removal on tattoos can become a lot more accurate and the results can be a lot more impressive. Why? Because the laser can target the macrophages specifically, meaning that, over time, the tattoo will fade entirely because there will be fewer and fewer pigments to swallow up.