A furrowed brow is the facial expression created when you pull your eyebrows downward and together, producing vertical lines between your eyebrows and horizontal creases across the bridge of your nose. It’s one of the most universally recognized expressions in human communication, signaling everything from deep concentration to confusion, anger, or sadness. You’ve almost certainly made this face thousands of times without thinking about it.
The Muscles Behind the Expression
Two small muscles do most of the work. The corrugator supercilii muscles are a pair of pyramidal muscles that sit deep beneath the skin of your forehead, just above each eye. They have two parts: one pulls your eyebrows inward toward each other, and the other pulls the inner edge of each brow downward. Together, these actions create the vertical creases between your eyebrows.
A second muscle called the procerus runs vertically along the bridge of your nose. When it contracts, it pulls the skin between your eyebrows downward, adding horizontal creases to the mix. These muscles work as a team, along with the ring-shaped muscle surrounding each eye, to hold your brow in position. When they all contract at once, you get the full furrowed look: lowered brows, vertical lines in the center, and a tightened, compressed appearance across the upper face.
What a Furrowed Brow Communicates
In conversation, a furrowed brow acts as a powerful nonverbal signal. Research in face-to-face interaction has found that it’s strongly associated with communicative problems, essentially telling the other person “I don’t have enough information” or “I’m not following you.” When study participants saw their conversation partner furrow their brow, they responded by speaking longer, adding roughly 8 to 11 extra words to their answers. The expression prompted speakers to clarify and elaborate without a single word being said.
Furrowing is also linked to negative emotions, particularly anger. Raised eyebrows tend to signal positive emotions like surprise, while lowered, furrowed brows skew negative. But the expression isn’t limited to emotion. People furrow their brow when concentrating on a difficult task, squinting in bright light, reading fine print, or simply thinking hard. Context determines the meaning. The same muscle contraction can read as fury in one situation and focused attention in another.
Why Humans Evolved This Expression
Researchers at the University of York have proposed that early humans had large, prominent brow ridges that served as a display of physical dominance. As human faces evolved to become smaller and flatter over hundreds of thousands of years, the brow region became more mobile and expressive. The shift reflects a broader change in human social life: moving from a world where looking intimidating was advantageous to one where cooperation, recognition, and empathy mattered more. Flexible eyebrows allowed for a much richer range of social signals, from the quick “eyebrow flash” you give someone you recognize across a room to the slow furrow that tells a friend you’re worried about them.
The Link Between Furrowing and Mood
There’s an interesting feedback loop between your facial muscles and your emotions. The facial feedback hypothesis suggests that the physical act of making an expression can intensify the emotion associated with it. In one study, researchers had participants perform a task that covertly caused them to contract their brow muscles while viewing unpleasant images. Those participants reported feeling significantly more sadness than people whose brow muscles were inhibited from contracting. In other words, furrowing your brow doesn’t just reflect how you feel. It can make a negative feeling worse.
Psychiatrists have recognized this connection for over a century. In 1872, Charles Darwin described the corrugator muscles as “grief muscles.” A few years later, German psychiatrist Heinrich Schüle coined the term “omega melancholicum” for the distinctive pattern that appears on the forehead during prolonged depression: two vertical slits between the eyebrows joined at the top by a horizontal crease, forming a shape resembling the Greek letter omega (Ω). This “omega sign” results from excessive, sustained contraction of the corrugator and procerus muscles, confirmed by electrical recordings of muscle activity in depressed individuals. While it isn’t specific enough to diagnose depression on its own (a similar pattern shows up in certain neurological conditions like progressive supranuclear palsy), it remains a useful clinical observation when combined with other symptoms.
How Furrowing Creates Permanent Lines
When you furrow your brow, the lines that appear are “dynamic” wrinkles. They show up during the muscle contraction and disappear when your face relaxes. Over years of repetitive contraction, though, those temporary creases become permanent. The repeated tugging of muscle on skin triggers structural changes in the deeper layers of your skin. Cells called fibrocytes ramp up their activity and gradually remodel the connective tissue beneath the surface, etching the lines into place. These are called “static” wrinkles, and they remain visible even when your face is completely at rest.
The most common result is the pair of vertical lines between the eyebrows, often called “elevens” or “11 lines” because they look like the number 11. Some people also develop a horizontal crease across the nose bridge from the procerus muscle. How quickly these lines become permanent depends on genetics, skin type, sun exposure, and how frequently and intensely you furrow throughout the day. People who spend long hours concentrating, squinting at screens, or experiencing chronic stress tend to develop them earlier.
Treating Deep Furrowed Lines
The most common cosmetic treatment for furrowed brow lines involves injecting a neurotoxin (sold under brand names like Botox, Dysport, and Xeomin) into the muscles responsible for the creasing. The injection temporarily weakens the corrugator and procerus muscles so they can’t contract as strongly, softening both dynamic lines and, over repeated treatments, the static ones as well. A standard session involves five small injections across the area between the eyebrows.
At standard doses, the effects typically last three to five months before the muscles gradually regain full function. Higher doses can extend that duration. With repeated treatments over time, the static lines that persist at rest tend to progressively improve because the skin gets a sustained break from the constant mechanical stress of muscle contraction.
Beyond cosmetics, there’s a therapeutic angle. Because of the feedback loop between facial expression and mood, some researchers have found that injections in the furrowed brow area can reduce depressive symptoms, likely by breaking the cycle in which the physical expression of distress reinforces the emotional experience of it.