Latisse is the first and only prescription treatment approved by the FDA for inadequate or insufficient eyelashes, growing them longer, fuller, and darker. Latisse makes lash growth possible because of its active ingredient: Bimatoprost. Latisse is easy to use and effective. It is a once-a-day treatment that is applied topically to the base of your upper eyelashes. Latisse works gradually and remarkably — starting at 4 weeks with full results after 16 weeks.