Facial Expressions, Frown Lines, and Everyday Habits

Faces are made to move. A laugh crinkles the corners of your eyes. Surprise lifts your forehead. Concentration pulls your brows together. Each of those expressions is a set of small muscles contracting under the skin, and each one leaves a fold for a moment before your face relaxes again.

This article looks at how those folds relate to lasting lines, where everyday habits fit in, and why we think the honest answer is more reassuring than the anti-aging aisle might suggest.

Lines that come and go, and lines that stay

It helps to think about two kinds of lines.

Expression lines appear when you make a face and fade when you relax. Frown, and creases form between your brows. Relax, and they soften or disappear. Practitioners often call these dynamic lines because they depend on movement.

Lines at rest are the ones you can see even when your face is calm. They tend to show up gradually over many years.

The two are connected. In its guidance on reducing premature skin aging, the American Academy of Dermatology explains that when you make a facial expression, you contract the underlying muscles, and that if you repeatedly contract the same muscles for many years, these lines become permanent.

The key words there are repeatedly and many years. One frown doesn’t do anything lasting. Expressions only matter in this sense as patterns.

Where expression lines usually appear

Different expressions involve different muscles, so lines tend to form in predictable places:

• Between the brows. Frowning and concentrating bring the brows down and together. A 2024 paper in the Journal of Cosmetic Dermatology describes the typical vertical lines here as forming through contraction of the corrugator supercilii and procerus muscles. These are the lines often nicknamed the “11s.”
• At the outer corners of the eyes. Smiling and squinting both crinkle this area, where the familiar “crow’s feet” form.
• Across the forehead. Raising your eyebrows, in surprise or just out of habit, creases the forehead horizontally.

Expressions are only part of the story

It’s worth being clear: facial expressions are one factor among many in how skin changes over time, and not the biggest one you can control.

The first recommendation on the AAD’s list is to protect your skin from the sun every day, because ultraviolet light speeds up skin aging. Its list also includes not smoking, and it covers a range of other everyday factors. Genetics and the natural process of getting older play their part too, and no habit change can stop that process.

So if you’ve noticed lines between your brows, there’s no reason to blame yourself for having an expressive face. That’s not how any of this works.

Expressions vs. habits

There’s an important difference between expressing and holding.

Laughing with friends, looking surprised, frowning at a confusing plot twist: these are expressions. They come and go, and they’re part of being you. Nobody should try to stop them.

A habit is different. It’s the squint you hold for twenty minutes while reading small text. It’s the furrow that settles in during a long work session and stays put without you noticing. These are repetitive, often unconscious, and usually have nothing to do with how you feel. They’re just tension your face picked up along the way.

That second category is where awareness can help. You can’t (and shouldn’t) stop expressing yourself, but you can learn to notice tension you never meant to hold, and let it go.

A gentler way to think about it

Korean skincare culture is often associated with gentle, consistent daily care, with the small things done regularly rather than dramatic fixes. We like applying that same spirit to facial habits. Not fighting your face, but paying kind attention to it.

In practice, that might look like:

• Wearing sunscreen every day, which the AAD puts first on its list
• Wearing sunglasses on bright days, which the AAD notes can help reduce lines caused by squinting
• Making screens easier to read so your face doesn’t have to work as hard (see Why Do We Squint at Our Phones?)
• Noticing held tension and softening it when you catch it

What awareness can and can’t do

Here’s the honest version.

Awareness can help you notice habits that are otherwise invisible to you. Once you notice them, you can choose to relax, adjust your screen, or take a break. Many people also find a relaxed face simply feels better.

Awareness can’t prevent aging, erase existing lines, or guarantee any particular cosmetic result. Neither can Squintly. We built Squintly as a habit-awareness tool, not a treatment. It uses your phone’s front camera and on-device facial tracking to notice sustained squinting or brow furrowing, then gives you a gentle vibration so you can relax. What you do with that moment is up to you.

If you have specific concerns about your skin, a board-certified dermatologist is the right person to talk to.

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This article is for general information and isn’t medical or dermatological advice.