Paul Mitchell Tea Tree Scalp Care Regeniplex Tonic is for anyone who wants fuller, thicker-looking hair. This stimulating scalp treatment helps to generate the optimal scalp environment to facilitate the growth of stronger, fuller, thicker hair. 85% of people* saw an increase in hair volume and strength after use of this leave-in treatment. Promote new growth and add fullness today. Formulated to be paraben-free and gluten-free with a botanical scent.