Why an eyelash serum? As well as hair, eyelashes can also be subject to aggression. Too vigorous removal of make-up, frequent use of the eyelash curler, as well as false eyelashes and extensions, can cause the eyelashes to weaken and break. Cils Booster Lash Revitalizing Serum is a real treatment that takes care of your eyelashes, fortifying and strengthening them. Apply it twice a day, in the morning and in the evening. Start by cleaning the eye area. Apply the serum along the lash line as a liner, and then as a mascara from the base to the tips. Wait a few minutes before proceeding with the application of eye makeup. Extra tip: For even thicker lashes, apply Primer Cils Booster XL on your lashes and follow your favorite mascara.