Ever looked in the mirror and wondered why your mouth naturally turns downward even when you’re feeling perfectly fine? It’s frustrating. You’re happy, but your face is telling a different story—one of chronic grumpiness or exhaustion. That little "frown maker" is actually a specific piece of anatomy called the depressor anguli oris muscle.
It’s small. It's triangular. And it's incredibly powerful.
Basically, this muscle lives in your lower face, stretching from your jawline up to the corners of your mouth. When it contracts, it pulls the corners of your lips toward your chin. Most people don’t even know it exists until they start noticing "marionette lines" or a permanent downturned expression.
Honestly, your face is a complex map of tug-of-war. For every muscle that pulls up, there’s another pulling down. The depressor anguli oris muscle (let’s just call it the DAO from here on out) is a "depressor" muscle, meaning its primary job is to yank things south. In the world of facial expressions, it’s the primary driver of sadness, grief, and disapproval.
Anatomy of the DAO: It’s All in the Jaw
The DAO originates from the oblique line of the mandible. If you run your finger along your jawline, somewhere between your chin and the back of your jaw, that’s the starting point. It then tapers upward to insert into the "modiolus"—a fancy medical term for the dense fibromuscular hub at the corner of your mouth where several muscles meet like a busy intersection.
It’s not working alone.
It overlaps with the platysma (that thin sheet of muscle in your neck) and sits right next to the depressor labii inferioris. Anatomically speaking, it’s a superficial muscle. This means it’s right under the skin, which is exactly why its movements are so visible. When you’re upset, the DAO tenses up. Over decades of life, that repetitive tension can actually change the resting shape of your mouth.
Physical therapists and dermatologists often look at the DAO as a key player in facial aging. As we lose collagen and fat in our cheeks, the upward-pulling muscles (the levators) get weaker. Meanwhile, the DAO stays strong, pulling the corners of the mouth down into those deep folds that make people look perpetually "over it."
The "RBF" Connection and Emotional Signaling
Have you heard of "Resting Bitch Face"? Or maybe just "Resting Sad Face"?
A lot of that comes down to DAO hyperactivity. In some people, this muscle is just naturally more "toned" or tight than in others. Dr. Jean Carruthers, a pioneer in the use of cosmetic injectables, has often noted that the mouth area is one of the most expressive parts of the human face. If your depressor anguli oris muscle is constantly "on," you’re sending signals of negativity to the world without realizing it.
It’s a feedback loop.
There’s a psychological theory called the facial feedback hypothesis. It suggests that our facial expressions can actually influence our moods. If your DAO is pulling your mouth down, your brain might receive subtle signals that you are, in fact, unhappy. This creates a cycle where physical tension leads to mental stress, which leads to more muscle tension.
When the DAO Goes Rogue: Medical and Cosmetic Issues
Sometimes the DAO causes more than just a frown. In cases of facial nerve palsy or Bell’s palsy, the balance between the muscles on either side of the face is thrown completely out of whack. If one side’s DAO is working and the other isn't, your smile will look crooked. You’ll have a noticeable asymmetry that can affect eating, speaking, and—of course—self-confidence.
Then there’s the cosmetic side of things.
📖 Related: Being a 10 Body Fat Man: What Getting Lean Really Feels Like
The most common way people deal with a hyperactive depressor anguli oris muscle is through neurotoxins like Botox or Dysport. A skilled injector will put a tiny amount of toxin directly into the DAO. This temporarily relaxes the muscle.
The result?
The "upward" muscles finally win the tug-of-war. The corners of the mouth return to a neutral position. It’s a subtle change, but it can make a person look years younger and significantly more approachable. However, if you hit the wrong spot—like the depressor labii inferioris—you might end up with a lopsided smile for three months. That’s why knowing the exact anatomy is so critical for practitioners.
Exercises, Stretches, and Natural Management
You don't always need needles.
Some people swear by "face yoga" or facial exercises to counteract the downward pull. While the science on face yoga is still a bit mixed, the logic is sound: strengthen the zygomaticus muscles (the ones that help you smile) to provide a better counterweight to the DAO.
One common stretch involves placing your index fingers on the corners of your mouth and gently pulling outward while trying to purse your lips. You’re essentially creating resistance for the DAO. Another trick is focusing on "tongue posture." By pressing your tongue against the roof of your mouth (a technique often called mewing), you provide more internal support for the lower facial structure, which can subtly lift the area surrounding the mouth.
Massage helps too.
📖 Related: Ideal weight 5 6 female: Why the Charts Are Kinda Lying to You
Taking two fingers and performing small, circular motions along the jawline where the DAO originates can release some of that built-up tension. Think about how much stress we carry in our jaws. Most of us are clenching all day. That clenching engages the masseter, but it also triggers the DAO. Relaxing the jaw is the first step to relaxing the mouth.
Why We Can't Just "Turn It Off"
Evolutionarily, the depressor anguli oris muscle is vital. We need it to communicate.
Non-verbal communication is about 70-90% of how we interact. If we couldn't express sadness, disappointment, or empathy through a downturned mouth, our social cohesion would suffer. We use the DAO to show we understand someone else's pain. It’s a tool for human connection, even if it’s the cause of those pesky marionette lines we hate seeing in photos.
It’s also involved in complex movements like speech. Try saying the letter "F" or "V" without any downward movement of the lower lip area. It’s nearly impossible. The DAO provides the stability needed for the lower lip to move independently of the rest of the face.
Actionable Steps for a Balanced Smile
If you’re concerned about how your DAO is affecting your appearance or your mood, you don't have to just live with it.
- Audit your "resting" face. Set a timer on your phone for three times a day. When it goes off, check: is your jaw clenched? Are the corners of your mouth turned down? Simply being aware of the tension can help you release it.
- Consult a specialist. If the downturn is significant, talk to a dermatologist or a facial plastic surgeon. They can determine if your DAO is truly hyperactive or if the "frown" is actually caused by volume loss in the cheeks that requires filler rather than muscle relaxers.
- Focus on the "Upper" Face. Often, we focus on the mouth because that’s where the lines are, but strengthening the cheek muscles through targeted exercises can provide a "natural lift" that offsets the DAO’s pull.
- Watch your posture. Believe it or not, looking down at a smartphone for six hours a day (tech neck) puts incredible strain on the platysma and the DAO. Keep your chin up—literally—to reduce the mechanical pull on your lower face.
The depressor anguli oris muscle isn't the enemy. It's just a very hard-working muscle that sometimes forgets how to relax. By understanding its anatomy and its role in your expressions, you can take better control of your facial health and the "vibe" you put out into the world.
Stop clenching. Breathe. Let the corners of your mouth drift back to neutral. Your brain—and your jawline—will thank you.