Obagi Nu-Cil™ Eyelash Enhancing Serum is designed to target the growth phase of the lash cycle to support overall lash improvement. Over time the natural lash cycle can be altered by factors such as hormones, stress level, or the aging process causing a decrease in volume, density, condition, and pigment. Thanks to NouriPlex™ technology, a unique blend of 4 key ingredients nourish lashes for a more luscious, thicker, and defined appearance with results that continuously build day after day.