Hair Tattoo - Scalp micropigmen1xtion, SMP, Hair Shading or Hair Simulation is a cosmetic procedure which involves using microneedles to inject a special ink pigment into the scalp area, drawing on a technique similar to tattooing to imitate the appearance of closely cropped hair. micropigmen1xtion can help create an impression of greater density, and it can be used on its own or alongside other hair restoration methods.