Smile lines: why yours are deeper on one side, and 5 things that actually help
UpdatedWritten by Megan Caldwell
Attending Dermatologist at Northwestern Medicine Dermatology Naperville · Last updated: August 2026
Smile lines, or nasolabial folds, are the creases running from the sides of your nose to the corners of your mouth. Everyone has them, at every age. They deepen for three reasons that have nothing to do with your pillow: the cheekbone flattens and midface volume descends, sun damage and smoking break down collagen and elastin, and every smile folds the skin along the same line. You cannot remove them permanently, and the Cleveland Clinic says so directly. What you can do is slow the deepening, and correct one specific imbalance. If one of your smile lines is visibly deeper than the other, the usual causes do not explain it: sun and smiling hit both sides about equally. Sleep position does not. You spend roughly 65% of the night on one side, with the weight of your head pressing half your face into a surface. Here is what causes smile lines, how to get rid of the treatable part, and why the side you sleep on shows up in the mirror.
In this article
- What are smile lines, and what causes them?
- Why are your smile lines deeper on one side?
- Can you get rid of smile lines?
- How do you get rid of smile lines? What actually helps, ranked
- Does your pillowcase affect smile lines?
- Frequently asked questions
What are smile lines, and what causes them?
A nasolabial fold is not really a wrinkle. It is a structural boundary. The muscles that lift the corner of your mouth anchor into the skin along that line, so the fold appears on a smooth 6-year-old face the moment they smile. What changes with age is depth: the cheek fat pad sits above the fold and slowly descends, so instead of a crease that shows up when you smile, you get a shelf that stays visible at rest. That is why the fix depends on the cause. Five things drive depth, and they are not equal.
| Driver | What it does | How much it matters |
|---|---|---|
| Midface volume loss | Cheekbone flattens, the cheek fat pad descends and folds over the crease | Largest driver from your mid-30s on |
| Sun damage and smoking | Destroy collagen and elastin, so folded skin stops springing back | Second largest, and almost entirely preventable |
| Repeated expression | The same muscles pull the skin along the same line, thousands of times | Constant, and normal anatomy rather than damage |
| Weight change | Rapid loss leaves loose skin; gain adds fullness that drags downward | Variable, and often the fastest visible change |
| Sleep position | Compresses and drags one side of the midface for hours a night | Smallest of the five, but the only one that acts on one side |
Aging, sun, smoking and weight-change causes per the Cleveland Clinic. Sleep-surface mechanics per Anson, Kurtz and Fulton, "Sleep Wrinkles: Facial Aging and Facial Distortion During Sleep," Aesthetic Surgery Journal, 2016.
Why are your smile lines deeper on one side?
Look at the top four drivers again. Sun reaches both cheeks, you smile with both sides of your face, and collagen declines everywhere at once. None of them produce a lopsided result.
Sleep is the one exposure that is not symmetric. Most people have a side they default to and return to it for decades. A 2016 review in the Aesthetic Surgery Journal treated this as its own category, finding that sleep wrinkles "form in response to distortion created when the face is pressed against any sleep surface" through compression, tension and shear, and that they differ from expression wrinkles in mechanism, location and direction. The lateral position accounts for about 65% of sleep time.
This is accepted enough that the Cleveland Clinic puts it in its own prevention advice for nasolabial folds: "Sleep on your back. This can help gravity work against laugh lines. If you're a side sleeper, try to switch sides regularly." That is a medical institution telling you to change how you sleep, on a page about smile lines.
Two caveats. Some facial asymmetry is skeletal and has been there since childhood, so not every uneven fold is a sleep habit. And sleep position is still the smallest of the five drivers. It is simply the one that explains what you noticed in a photograph.
Can you get rid of smile lines?
Not permanently. The Cleveland Clinic is unusually blunt about it: "There's no way to prevent nasolabial folds permanently. Treatments can work for a few months or even years, but you can't completely stop the signs of aging." Softening is realistic, erasing is not, and what follows is ranked by how much difference each option makes rather than by how easy it is to sell.
How do you get rid of smile lines? What actually helps, ranked
- Daily sunscreen, and no smoking. These protect the collagen and elastin that let folded skin recover its shape. Broad-spectrum SPF 30 or higher, every day. Nothing else here returns as much over 10 years.
- A retinoid at night. The best-evidenced topical for building collagen. Start low, two or three evenings a week, and build up. Irritated skin is not the goal.
- Replace volume, if the fold is deep. Filler placed in the cheek rather than the fold addresses the actual cause, which is descent. Results last months to a couple of years. Go to a board-certified clinician: overfilled nasolabial folds are a recognizable outcome.
- Sleep on your back. The Cleveland Clinic's own recommendation. It removes the compression completely, and it is the hardest thing here to sustain, since you cannot supervise your position once you are asleep.
- Reduce the drag at the surface. If you cannot stay on your back, position is fixed and the surface is the only variable left. Compression comes from the weight of your head and cannot be removed. Shear depends on how much the fabric grips your skin.
Does your pillowcase affect smile lines?
It affects one of the three forces, and being precise about which one is the whole point. The 2016 review examined sleeping position, not fabric, and did not test or endorse any pillowcase material. What it established is that shear distorts the tissue. Shear is friction: the sideways pull as your cheek moves against the surface each time you turn.
Friction is measurable, which makes it one of the few parts of this conversation where you can check a number instead of a promise. Cotton's surface roughness measures about 0.25 µm. CloudThera™, Dreamey's engineered eucalyptus lyocell, measures 0.11 µm, which is 56% less friction, and it is smoother than silk at 0.15 µm. It also moves 34% more moisture vapor than cotton (570 vs 425 g/m²/h) and harbors 3x less surface bacteria per Hohenstein Institute testing, so your cheek is not resting in a damp fold for 8 hours.
That surface is not something eucalyptus gives you by default. It comes from DermaWeave™, the proprietary finishing process that refines each 10 to 12 µm fiber, which is why the commodity eucalyptus viscose sold for $40 pills by the second wash and publishes no roughness figure at all. Ask for the number and see whether one exists.
What that does and does not mean: a smoother surface reduces the drag component, which is why the honest claim is fewer sleep creases. No fabric erases a fold caused by volume loss, no fabric replaces sunscreen or a retinoid, and no fabric outperforms simply sleeping on your back. Anyone selling a pillowcase as an anti-aging treatment is well past what the evidence supports. It is one small controllable variable, running the whole 8 hours.
A DermaWeave-finished 0.11 µm surface, 56% less friction than cotton and smoother than silk's 0.15 µm, so there is less sideways drag on the side of your face you sleep on. OEKO-TEX Standard 100 certified.
One practical note: swap the case you actually sleep on, not the decorative one. The same forces act across the rest of the bed, which our guides to the 2 kinds of neck wrinkles and silk vs satin pillowcases cover in more depth.
Pillowcases and sheets together. The same 0.11 µm surface and 570 g/m²/h moisture transmission everywhere your skin touches, made in a 99.5% closed-loop process and PETA-approved vegan.
Frequently asked questions
Why are my smile lines so deep?
Usually midface volume, not the skin at the fold. As the cheekbone flattens and the cheek fat pad drifts downward, tissue stacks above the crease and casts a deeper shadow. Sun damage compounds it by weakening the collagen that would hold the cheek up, and rapid weight loss can unmask it in months. Treating the fold while ignoring the cheek is the common mistake here.
How do you get rid of smile lines naturally?
You can soften them without injectables, but expect modest results over months, not weeks. Daily sunscreen, a retinoid, stable weight and stopping smoking address the causes that are reversible, and sleeping on your back removes one-sided compression. Facial massage and face yoga temporarily improve how the area looks by moving fluid, but no exercise rebuilds a cheekbone or a fat pad, so treat those claims carefully.
Does Botox work on smile lines?
Generally no, and it is the wrong tool for this line. Neurotoxins work by relaxing a contracting muscle, which suits forehead and frown lines. A nasolabial fold is mostly volume and structure, so relaxing the muscles that lift your mouth risks an uneven smile or a drooping lip rather than a smoother face. Filler placed in the cheek is the standard approach for depth.
Does sleeping on one side make your face asymmetrical?
It can contribute over years, though it is rarely the whole story. Side sleeping applies compression, tension and shear to one half of the face for most of the night, and the Aesthetic Surgery Journal review found these forces produce wrinkles in locations that differ from expression lines. The Cleveland Clinic advises side sleepers to switch sides regularly for this reason. Bear in mind that mild skeletal asymmetry is normal and present in almost everyone.
Does a silk or eucalyptus pillowcase prevent smile lines?
No. Neither prevents them, and a brand telling you otherwise is overselling a real but small effect. A smoother surface reduces friction, one of three forces involved in sleep creasing, and it does nothing about the volume loss that drives most of the depth. On friction the measured figures are 0.25 µm for cotton, 0.15 µm for silk and 0.11 µm for engineered eucalyptus lyocell. Worth having, far behind sunscreen and back sleeping.
Less drag on the side you sleep on.
A 0.11 µm DermaWeave surface, 56% less friction than cotton and smoother than silk. Measured, not marketed. Better skin, hair & sleep starts tonight.
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