In the past half decade, the popularity of Botox in the U.S. has skyrocketed, with a 40.6 percent increase in procedures according to the latest figures from the American Society for Aesthetic Plastic Surgery (ASAPS), and a 5.1 percent rise since 2017. Last year, over 1.5 million Botox injections were carried out.

Researchers at Northwestern University wanted to investigate why so many of us undergo the treatment.