The bumble and bumble thickening serum is your ticket to thicker stronger strands created especially for those with lifeless fine and thinning hair this nightly leave in treatment will boost fullness it fattens and fortifies the strands over time to boost natural thickness resulting in some seriously glamorous hair before bed dispense about 2 or 3 pumps of serum into the hands and work into the roots and through the hair those with longer hair may need a little more to make sure its