Why Your Smile Lines Are Getting Deeper — And When to Do Something About It

They’re sometimes called laugh lines, sometimes nasolabial folds, sometimes smile lines. The name suggests something benign — even joyful. But when they deepen past a certain point, they stop reading as an expression of happiness and start reading as a sign of age. And unlike actual smiling, they’re there all the time.

Smile lines — the folds that run from the sides of the nose down to the corners of the mouth — are among the most searched aesthetic concerns. They deepen gradually enough that many people aren’t sure exactly when they became noticeable.

And they’re driven by several intersecting factors, which is why treating them effectively requires understanding which factors are actually at play in your face:

• Mid-face volume loss: As cheek fat pads descend, they create a “bulge” of tissue that hangs over the mouth area.
• Loss of skin elasticity: Thinning skin loses its ability to “snap back” after smiling, causing creases to linger.
• Repetitive muscle movement: Constant contraction of the facial muscles eventually etches these lines into the dermis.

Treating these folds as isolated “cracks” to be filled is a classic example of poor filler technique. When an injector simply “stuffs” the line without addressing the structural sagging from the cheeks above, the result is often a face that looks heavier, wider, and distinctly unnatural.

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The nasolabial fold is not simply a line in the skin. It marks the junction between two different anatomical zones — the cheek and the upper lip — which move independently when you express emotion. Every smile, every laugh, every conversation deepens the crease slightly over time.

But movement alone doesn’t explain why the fold deepens so significantly from the mid-30s onward. Several structural changes amplify the effect:

The cheek fat pads that sit above the fold deflate and descend with age. As the overlying tissue loses its volume and falls slightly forward and downward, it piles at the nasolabial groove, deepening the crease. This is not a line created by movement — it’s a fold created by tissue accumulation above it.

As collagen and elastin decline, the skin covering the cheek loses its ability to sit firmly over the underlying structure. Looser skin is more prone to folding at natural junction points.

The maxilla (upper jaw) subtly recedes with age, reducing the projection that once supported the cheek and upper lip. Less forward projection means more of the soft tissue descends toward the fold.

The retaining ligaments that hold the cheek tissue in place weaken over time, allowing greater descent of the soft tissue above the fold.

“Patients often come in asking me to fill their smile lines,” says Dr. Low Chai Ling, Medical Director, SW1 Clinic. “But what they often actually need is midface volume restoration. When the cheek tissue is supported correctly, the fold naturally softens. Filling the fold directly without addressing the descent above it can lead to an unnatural, heavy look.”

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This is one of the most clinically important nuances in smile line treatment. The nasolabial fold is not always best treated by injecting filler directly into it.

Think of it like a curtain rod. If a heavy curtain is sagging and bunching at the base, the solution isn’t to stuff material into the pile at the bottom. You need to lift and support the rod it hangs from.

Similarly, when the fold is created by descending cheek tissue, the anatomically correct approach is to restore volume in the midface — the cheek fat pads above the fold — which lifts the tissue and reduces the folding effect. Direct filler into the fold is sometimes used in addition to this, but rarely as the sole intervention. In fact, ignoring the structural “rod” and only filling the “pile” at the bottom is a classic example of poor filler technique, often resulting in a face that looks heavier and wider rather than truly lifted and refreshed.

“The approach to smile lines has shifted significantly in the last decade,” says Dr. Chua, SW1 Clinic. “We used to fill the fold directly almost by reflex. Now we understand that volumising the midface first — restoring the foundation — produces a more natural and longer-lasting result.”

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Hyaluronic acid filler placed in the deep cheek fat compartments restores the volume and projection that supports the overlying skin. As the midface is lifted, tissue that was descending into the fold is supported, and the fold softens naturally.

At SW1 Clinic,
addresses the midface compartments with precision — restoring facial proportions while simultaneously reducing the appearance of the nasolabial fold.

Where the fold is particularly deep or where direct correction is appropriate, hyaluronic acid filler can be placed within the fold itself. The filler fills the groove from below, softening the transition. A soft, low-viscosity product is typically used here to avoid an overfilled appearance.

at SW1 Clinic addresses facial folds using precise filler placement — addressing the nasolabial area with attention to natural proportion and facial balance.

For patients whose smile lines are compounded by skin laxity, energy-based treatments that stimulate collagen and tighten the overlying skin can be a useful adjunct. HIFU and radiofrequency treatments work in the deeper tissue layers to provide lift and support — reducing the degree to which skin folds at natural junction points.

The
at SW1 Clinic can be used to improve skin quality and laxity in the midface zone, complementing filler treatments for a more comprehensive result.

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A 2014 study in the
confirmed that midface volume restoration with hyaluronic acid filler produces significant softening of the nasolabial fold as a secondary effect — supporting the indirect treatment approach [1]. A separate study published in
demonstrated the importance of treating the deep fat compartments of the face when addressing nasolabial folds, rather than focusing solely on the fold itself [2].

Research also confirms that combination approaches — volume restoration plus skin-tightening — produce longer-lasting results with higher patient satisfaction than single-modality treatment [3].

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Farah, 47, had been bothered by her deepening smile lines for several years. She’d read about filler and assumed she would have the lines directly filled.

After consultation, her doctor recommended midface volume restoration as the primary approach — addressing the cheek tissue descent that was driving the fold. Two weeks after treatment, the lines had softened noticeably. “I didn’t expect so much improvement just from the cheek treatment,” she said. “I thought I’d need the lines filled directly, but the lift made so much more difference than I’d imagined.”

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Smile lines have more than one cause, and the most effective treatment depends on understanding which cause is predominant in your individual anatomy. A consultation at SW1 Clinic will assess your midface volume, skin quality, and the specific anatomy of your fold to recommend the most appropriate approach.

Often, the clinical decision rests on the fundamental distinction of botulinum vs fillers:

• Botulinum Toxin: This is the tool of choice if the lines are primarily “dynamic”—meaning they are caused by the overactive muscles used when you smile or laugh. Relaxing these specific muscles can soften the depth of the fold without adding any physical mass.

• Dermal Fillers: These are used when the fold is “static” or structural—caused by the loss of fat and bone support in the cheeks that allows the skin to drape forward. In this case, adding volume (or “lifting” from the cheekbones) is the only way to physically smooth the crease.

Using the wrong intervention—or failing to recognize when a combination of both is needed—is a primary reason why some results look “unfinished” or unnatural. By identifying the root cause, we ensure your treatment plan preserves your natural expressions while refreshing your overall appearance.

Book at 8218 3273 to arrange a consultation.

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[1] Raspaldo, H., Baspeyras, M., Bellity, P., et al. (2011). Upper- and mid-face anti-aging treatment and prevention using onabotulinumtoxin A: the 2010 multidisciplinary French consensus — part 1.
, 10(1), 36–50. [VERIFY CITATION] [2] Lambros, V. (2007). Observations on periorbital and midface aging.
, 120(5), 1367–1376.

[3] Raspaldo, H. (2008). Volumizing effect of a new hyaluronic acid sub-dermal facial filler: a retrospective analysis based on 102 cases.
, 10(3), 134–142. [VERIFY CITATION]