Bitter lines, often referred to as marionette lines, are those little folds at the corners of the lips that pull the smile down, like a marionette. When these wrinkles deepen and trace their way across our face, they can quickly give us a stern, even sad expression, reminiscent of the face of a hand puppet. The main causes identified are:
Repeated contractions of the facial skin muscle, similar to the movements of a puppet, called DAO (Depressor Auguli Oris) which pulls the corner of the mouth downwards.
Aging, much like the aging of a puppet in a puppet show, leads to sagging skin, melting fat, and sagging of the lower face with age-related bone loss.
These oblique marionette lines rarely form before the age of 40. They are more visible in women, while men can easily hide them, a bit like hiding a puppet behind a curtain, under a beard. These lines can be more or less pronounced, depending on age.