The depressor anguli oris is a facial muscle that allows a person to move the corners of their mouth, specifically downward. The muscle sits on either side of the mouth.

Frowning involves activating the depressor anguli oris muscle as it pulls down the corners of the mouth. Depending on the strength of these muscles, some people may have more pronounced frowning expressions than others.

Individuals may wish to fix this with cosmetic procedures. Dermatologists and plastic surgeons can inject botulinum toxin into the muscle to improve what some people perceive as an overly frown-like expression.

Read more to learn about the depressor anguli oris, how this muscle helps individuals express emotion, and whether botulinum toxin can help with weak or overactive muscles.

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The depressor anguli oris is a facial muscle responsible for the downward pull of the mouth. It allows people to express emotions facially and, most notably, frown.

It is a paired muscle, which means there is one on each side of the face. Each muscle starts along the edge of the chin and stops at the corners of the mouth.

Click on the BodyMap above to interact with a 3D model of the depressor anguli oris muscle.

People sometimes refer to the depressor anguli oris as the “sadness muscle.” This is because it is responsible for pulling down or “depressing” the corners of the mouth, which occurs when a person frowns.

Like other facial muscles, the depressor anguli oris is an essential part of expressing emotion.

Some people perceive the depressor anguli oris muscle to be overactive, causing a persistent frown-like appearance. Issues with this muscle can make it difficult to smile, cause a lopsided smile, or cause excessive frowning.

Conditions that may affect the muscle include:

  • Bell’s palsy
  • Ramsay Hunt syndrome, an infection of a facial nerve
  • Lyme disease
  • trauma to the face

Some people may opt for cosmetic procedures to help manage this constant downward pull.

Botox, one trademark of the botulinum toxin, is one option. It can help eliminate the frowning appearance by blocking the nerve signals that make the muscles contract.

According to one older 2010 study, using Botox on the depressor anguli oris can help elevate the corners of the mouth and even create a temporary neck lift. However, there is insufficient research on Botox treatment for this muscle, so researchers do not fully know its risks and side effects.

Additionally, the effects of Botox are not permanent — it typically only lasts a few months.

While Botox injections carry fewer risks than surgical procedures, a person needs repeat injections to maintain results. Additionally, getting a Botox injection into the depressor anguli oris is an inpatient procedure and does not require a hospital stay.

The depressor anguli oris is responsible for pulling the corners of the mouth down. When the muscle is overactive or weak, it can look like a person is frowning when their face is at rest.

Some people choose Botox to change this appearance. While Botox is a relatively safe and simple procedure, some individuals need regular injections to maintain results.