As long as you keep your eyelashes in good condition it'll be fine. I notice their mascara is not hard to remove and doesn't take the eyelashes with it when it is removed at night. It does thicken but I would say it does not lengthen as much. I personally just take the brush and wiggle it into my eyelashes and pull the brush away. I usually do this several times.

If you want, to make it appear like you have more eyelashes you can always line your top and bottom line. It works for me!