Tattoos become permanent when they are injected into the dermis. The nature of the dermis and the mechanism of the immune system makes this possible.

Picosecond lasers used for tattoo removal require fewer treatments, cause fewer side effects, and result in reduced post-procedural downtime compared to nanosecond Q-switched lasers. They can clear some tattoos that are refractory to other forms of laser therapy, and there is a reduced risk of causing scarring and hypopigmentation.