A lash serum must disrupt eyelash hair development for it to work. Bimatoprost drops do that, say specialists. Most dermatologists and cosmetologists recommend it to lengthen, thicken, and darken eyelashes. Women and men use Careprost eye drops to grow their little lashes, the most popular Bimatoprost brand. The eyelash treatment stimulates healthy hair follicles and prevents lash loss. It may lengthen the hair growth cycle and boost the lash count.