Scalp Micropigmentation (SMP) A tattoo machine is used to create follicle-like replications by implanting pigment under the skin. This technique can be used for both men and women suffering from hair loss and thinning hair. Two to five sessions are needed to create your desired density. Sessions are done once a week until the look is complete. Results can last 5+ years with proper care and upkeep. A refresher touch up may be needed to combat further hair loss.