Every individual is different and so is every tattoo. And everyone’s health and immune system is different.
There is no specific science. However, we will consider the many variables before we can estimate the number of treatments you might need:
On average, you’ll need between 4-8 treatments but everyone reacts and heals differently. Some people might need more, some people need less.
And certain colours take longer than others. For example, black ink is the easiest to eliminate whereas colours like blues, greens and reds may require more sessions.