How does botulinum toxin treatment affect the depressor anguli oris muscle?

Botulinum toxin treatment of the depressor anguli oris muscle inhibits its contraction, leading to the elevation of the corners of the mouth and a reduction in marionette lines. This treatment can improve the appearance of a sad or sullen expression by enhancing the smile.

The depressor anguli oris muscle contributes to the formation of marionette lines and down-turned corners of the mouth by pulling the corners downward. Botulinum toxin injections target this muscle to partially inhibit its contraction. As a result, the corners of the mouth are elevated, reducing the appearance of marionette lines and improving facial expressions. The treatment is subtle and focuses on maintaining oral function while achieving aesthetic improvements. Effects are typically noticeable two weeks after treatment and last for about 2-3 months.