As anyone who’s had a tattoo for a while will tell you, they tend to fade over time. But why? Surely once you’re tattooed then that should be it? And if it fades, then why doesn’t it disappear completely? Well, get ready for a science lesson…
Basically, your skin is made up of two separate layers, an outer and inner layer. The outer layer is called the epidermis, and this layer heals itself easily. New skin cells grow underneath and over 3-4 weeks will gradually move up to the surface, replacing old skin. This is why you can get a scratch, but it’s gone a couple of weeks later.
The bottom layer, the dermis, is different. It’s usually protected by the epidermis, so doesn’t need to replenish itself every month. It is in this layer where a tattoo is injected, and because the dermis doesn’t regenerate like the outer layer, the ink stays where it is.
Ok, but this doesn’t explain why tattoos fade over time. Well, it comes down to the actual microscopic ink particles in your blood. They come in all different sizes, and some are bigger than others. Don’t forget, this ink is a foreign body, and your white blood cells see it as a threat. They’ll attack the ink particles and those small enough will be “eaten” by your white blood cells and removed from the body via the liver. You’ll literally piss out your tattoo. As for the bigger particles, the white blood cells can’t destroy those, so they stay in your body.
This is why tattoos fade over time. Some of the ink is taken by your body’s natural immune system, and the rest is left, meaning it fades over time as the ink is broken down.