The Latisse clinical trial examined 278 participants in 16 cities. Participants were given either Latisse solution or a placebo. Neither the participants nor their physicians knew which treatment they were receiving, so the trial was a “double-blind”, placebo-controlled trial, the gold standard of clinical trials. The participants were followed for four months. During the 16-week trial, participants were photographed and evaluated every four weeks. Investigators studied the length, fullness, and thickness of participants’ lashes. At the end of the trial, the results showed that Latisse improved lash length, fullness and thickness in 78% of patients.