Smile lines — also called laugh lines or, in clinical language, nasolabial folds — are one of the most common concerns patients bring to our consultation room. They are also one of the most frequently misunderstood. The common assumption is that smile lines are a surface wrinkle that can be simply filled in. In reality, the fold you see running from the side of the nose down toward the corner of the mouth is almost never just a skin problem. It is a structural boundary, and the way it deepens over time reflects changes happening in multiple layers of the face — skin, fat, muscle, and even bone.
This guide explains what smile lines actually are, why they form, how we assess their severity, and the full range of clinically appropriate treatment options available in Singapore today — from hyaluronic acid dermal fillers to PDO liquid threadlifts, HIFU, and biostimulator injections. The goal is not to sell you a single treatment. It is to help you understand your own face well enough to have a meaningful conversation with your doctor about which approach (or combination) is right for you.
What Are Smile Lines (and Why They Form)
The nasolabial fold is an anatomical structure, not a wrinkle. It exists in almost everyone from childhood — it is the natural boundary between the cheek and the upper lip region, created by the way facial muscles attach to the overlying skin. In young, well-supported faces, this fold is barely visible at rest and only becomes prominent when smiling. That is why it is called a "smile line" or "laugh line" in everyday language.
What changes with time is not that the fold appears from nowhere — it deepens. The surrounding tissue changes. The cheek above the fold loses volume and begins to descend. The skin loses collagen and elastin. Eventually, a line that was only visible during animation becomes a permanent feature of the face at rest. When patients say they want to treat their "smile lines", what they are really asking us to address is this shift — the point at which a dynamic fold has become a static one.
An important clinical distinction: The goal of smile line treatment is rarely to erase the fold completely. A fully flat midface looks unnatural — and is often a sign of overfilling. The aesthetic goal is to restore proportional support so the fold sits gracefully within a balanced face, rather than dominating it. Dr Cherie Lau's approach at MIRAE is focused on natural balance, not elimination.
The Real Causes of Smile Lines — It's Not Just Skin
Understanding why smile lines deepen requires looking at the face in layers. When a patient asks "why do I have smile lines at 35?", the honest answer is usually that multiple contributing factors are at play — and which one is dominant determines what treatment will work best for them.
The implication is important: smile lines caused predominantly by mid-cheek volume loss will not respond well to filler placed only in the fold itself. They need volume restored in the cheek. Smile lines caused by significant skin laxity and descent require lifting, not just filling. And smile lines that are still mostly dynamic — appearing during movement rather than at rest — may benefit from a very different approach than well-established deep folds. This is why the honest first step is always assessment, not treatment.
Assessing Severity: Early, Moderate or Deep Smile Lines?
In clinical practice, we broadly classify smile lines into three stages of severity. This is a simplified framework — real faces fall along a spectrum, and each patient's anatomy is unique — but it is useful for understanding where you are and what that typically means for treatment.
Early / Dynamic
The fold is visible only when smiling or speaking. At rest, the face looks smooth. There may be mild fine-line etching in the skin but no significant volume change or descent. Patients are often in their late 20s to mid 30s.
Moderate / Static
A visible fold is present at rest, deepening further during animation. Mild mid-cheek flattening and early descent become apparent. Patients typically notice this in their late 30s to 40s, though genetics and sun exposure can shift the timeline earlier or later.
Deep / Structural
A deep, well-established fold is present at rest. Significant cheek volume loss, tissue descent, and skin laxity are all contributing. The fold may extend into a "marionette line" running down past the corner of the mouth. Treatment typically requires combination therapy.
The stage guides the strategy. Early smile lines often respond well to a conservative approach — good skincare, sun protection, and potentially skin quality treatments or early collagen-stimulating work. Moderate smile lines are where direct intervention — filler, biostimulators, or liquid PDO threadlifts — typically enters the picture. Deep smile lines almost always require a layered approach, addressing volume loss, tissue descent, and skin quality in combination rather than isolation.
Treatment Options: From Fillers to Liquid PDO Threadlifts to HIFU
The honest answer to "what is the suitable treatment for smile lines?" is that there is no single suitable treatment. The right treatment depends on the cause, severity, and the rest of the patient's face. Below is an overview of the clinically relevant options and what each is actually good for.
Hyaluronic Acid (HA) Dermal Fillers
Most common first-line treatmentHA fillers are gel-like products made from a sugar molecule naturally found in the skin. For smile lines, they are used in two distinct ways: to restore volume in the mid-cheek (lifting the fold from above), and to directly soften the fold itself with softer, more pliable HA products. The choice of product — and more importantly, where it is placed — matters as much as the volume injected. Results are immediate, and a good HA treatment can last 9 to 18 months depending on product and placement.
Biostimulators (PDLLA / Collagen-Stimulating Injectables)
Progressive collagen remodellingBiostimulators such as poly-L-lactic acid (PDLLA) do not fill the fold in the way HA does. Instead, they stimulate the skin's own collagen production over months, producing a more gradual, structural improvement. This makes them useful for patients whose smile lines are driven by skin laxity and overall volume depletion rather than a single deep fold. Results build over 3 to 6 months and typically last up to 24 months as the newly formed collagen matures.
PDLLA + HA Hybrid Skin Boosters
Combination approachHybrid products combine the immediate volumising effect of HA with the collagen-stimulating properties of PDLLA in a single injection. For patients with moderate smile lines and generalised skin quality decline, this can produce both short-term visible improvement and longer-term structural support. See our dedicated guide on skin boosters in Singapore for how these compare.
PDO Liquid Threadlift
Lifting without surgeryPDO liquid threadlift uses fine, absorbable polydioxanone threads introduced into the deeper layers of the skin via micro-cannula to create structural support and stimulate collagen formation along the thread pathways. For smile lines caused by tissue descent, liquid PDO threadlift addresses the cause directly by repositioning the fallen cheek tissue — a result that filler placed into the fold cannot replicate. Read more in our Liquid PDO Threadlift Singapore price guide.
HIFU (High-Intensity Focused Ultrasound)
Structural lifting, no injectionHIFU delivers focused ultrasound energy to the SMAS layer at 4.5mm depth — the same layer a surgeon would address in a facelift. The thermal coagulation points trigger collagen remodelling and tissue contraction, producing a subtle lift of the midface and cheek. For smile lines where descent is the dominant factor but the patient prefers to avoid injections, HIFU is a strong option. Results develop over 3 to 6 months. See our full HIFU Singapore guide.
Morpheus8 RF Microneedling
Skin quality & early laxityMorpheus8 is not a primary treatment for deep smile lines, but it plays a valuable supporting role. For patients with a textural component to their smile lines — fine crepey skin, poor skin quality around the fold — Morpheus8 improves the overlying skin and can tighten early jowl-adjacent laxity. It is often combined with filler or liquid PDO threadlift rather than used alone for this concern. Read our Morpheus8 Singapore guide for full detail.
Skin Boosters (HA, PN, Exosomes)
Adjunct / skin qualitySkin boosters — whether hyaluronic acid, polynucleotides (PN), or exosomes — are not fold-filling treatments. They improve overall skin hydration, elasticity, and quality. For early smile lines where poor skin quality is the main concern, or as a maintenance treatment alongside filler or liquid PDO threadlift, skin boosters contribute to the long-term aesthetic outcome even if they do not directly treat the fold itself.
Anti-Wrinkle Injection
Targeted, selective useAnti-wrinkle injections are not a first-line smile line treatment. Smile lines are caused by volume loss and descent, not overactive muscle — so relaxing the muscle will not address the fold itself. Anti-Wrinkle Injections is occasionally used alongside filler in patients where an overactive nasal muscle contributes to the appearance of the fold during animation, but as a standalone treatment for the nasolabial fold, it is rarely appropriate. See our Anti-Wrinkle Injections guide for where Anti-Wrinkle Injections is genuinely effective.
Smile Line Fillers: Which One & Why It Matters
HA fillers are not all the same. Products differ in their cross-linking, elasticity, cohesivity, and how they behave when placed in tissue. For the smile line area, this matters more than most patients realise — because the fold spans multiple depths of tissue, and the product that suits a deep cheek placement is very different from the product that suits a superficial fold refinement.
In general, fillers for the smile line area fall into three functional categories. Structural, high-G-prime fillers are robust, lifting products placed deep in the cheek to restore the volume platform that supports the overlying tissue. These are the products that produce "lift" rather than just "fill". Mid-range fillers are used for the fold itself when direct treatment is needed — they integrate with tissue, move naturally with expression, and correct the line without appearing as a distinct cushion under the skin. Softer, lighter fillers are used for superficial refinement of the fold's surface texture where skin quality is also a concern.
A note on "the suitable filler for smile lines": There is no single suitable product. What determines outcome is the match between product properties, injection depth, volume distribution, and each patient's anatomy. A widely advertised premium brand placed poorly will produce a worse result than a modest product placed correctly. This is a case where the injector matters far more than the brand name on the syringe.
Filler vs Liquid PDO Threadlift vs HIFU vs Biostimulator: How to Choose
The most common question patients ask is how these options compare. Below is a simplified comparison — a consultation is the appropriate place to determine which is right for your specific anatomy, but this table gives a sense of how each treatment differs.
| Feature | HA Filler | Liquid PDO Threadlift | HIFU | Biostimulator |
|---|---|---|---|---|
| Primary action | Volume replacement | Mechanical lift + collagen | Structural lifting via SMAS | Progressive collagen stimulation |
| for | Moderate to deep folds, volume loss | Tissue descent, early to moderate sag | Mild to moderate descent without injections | Overall volume decline, skin laxity |
| Result onset | Immediate | Immediate (refines over 8–12 weeks) | Gradual: 3–6 months | Progressive: 3–6 months |
| Typical duration | 9–18 months | 12–18 months | 6–12 months | Up to 24 months |
| Downtime | Minimal (2–5 days possible bruising) | Mild (3–5 days) | Minimal (hours) | Mild swelling / firmness (3–5 days) |
| Reversibility | Yes (hyaluronidase) | Absorbs naturally over time | Non-reversible (naturally remodels) | Non-reversible (naturally remodels) |
| Pain level | Mild with numbing + lidocaine in filler | Mild with numbing | Moderate sensation during treatment | Mild with numbing |
| Combination potential | Strong — pairs with most modalities | Strong — pairs with filler, HIFU | Strong — pairs with filler, liquid PDO threadlift | Strong — pairs with filler |
Individual suitability and expected outcomes are determined during a consultation with Dr Cherie Lau. This table is for general educational reference.
The Decision Framework: Matching Cause to Treatment
Rather than asking "which treatment is suitable?", a more useful question is "which cause is dominant in my face?" The answer points naturally to the appropriate treatment. Here is how we approach this clinically at MIRAE.
If the dominant issue is mid-cheek volume loss
The fold is deep but the skin above it looks deflated and flat. Cheeks have lost their natural roundness. Addressed with structural filler placed in the cheek (lifting the fold from above), often with minimal direct filler in the fold itself. Biostimulators can play a supporting role over time.
If the dominant issue is tissue descent / sagging
The cheek tissue has fallen and is accumulating along the fold, creating a visible hammock over the upper lip. Filler alone will not lift the tissue — it may make the lower face look heavier. Addressed with liquid PDO threadlift and/or HIFU to reposition and support the tissue, with filler used selectively.
If the dominant issue is skin quality & fine-line etching
The fold is not very deep, but fine lines within it and poor skin quality (crepey, thin, dry) make it look more pronounced. Addressed with skin boosters, Morpheus8 RF microneedling, and daily skincare and sun protection. Filler may not be needed at all.
If the dominant issue is a deep, well-established static fold
The fold is visible at rest, deep, and clearly structural. Multiple contributing factors are present. Addressed with a combination approach — cheek volumisation, direct fold softening, structural lifting, and skin quality improvement — rather than any single treatment in isolation.
If the concern is primarily dynamic (visible only when smiling)
The fold is not yet static. In many cases, early preventive measures — consistent sun protection, medical-grade skincare, and skin quality treatments — are more appropriate than injectable intervention. Treating a purely dynamic fold with filler risks creating an unnatural resting face.
Treating the Face, Not Just the Fold
Dr Cherie Lau's approach to smile lines is grounded in the principle that the nasolabial fold is a reflection of the face around it. Treating the fold in isolation — without considering the cheek, the lips, the jawline, and the skin — produces the overfilled, unnatural results that patients often describe as looking "done". A measured, combination-aware approach prioritises facial balance: enough volume to restore proportion, enough lifting to counter descent, and enough skin quality improvement to refine the surface — no more, no less.
This often means we recommend doing less at the first session, reviewing the result, and building gradually. Good aesthetic medicine is rarely delivered in a single visit, and the patients who are happiest over the long term are usually those treated conservatively across multiple visits rather than maximally at one.
What to Expect: Procedure, Downtime & Results
Consultation & Assessment
Your first visit is a clinical assessment, not a treatment session. Dr Cherie Lau will examine your face at rest and in animation, discuss your concerns and goals, and explain what is contributing to your smile lines specifically. This is also when contraindications, medications, allergies, and any previous treatments are reviewed. A treatment plan is then proposed — often with more than one option — and a personalised quote is provided.
On the Day of Treatment
Topical numbing cream is applied 20 to 30 minutes before injectable treatments. The area is cleaned and prepared, and photographs are taken for your medical record (these are kept confidentially and are not used for advertising). The procedure itself — whether filler, liquid PDO threadlift, or biostimulator — typically takes 20 to 45 minutes for the nasolabial area depending on what is being done and whether adjacent zones are being treated in the same session.
Immediately After
For injectables, you may notice mild redness, small pinpoint marks at injection sites, and some swelling. Bruising is possible but not universal — ice and arnica can help. You are reviewed before leaving the clinic, and written aftercare instructions are provided. Most patients return to normal activities the same day, though some prefer to plan treatments ahead of a quieter weekend for comfort.
Aftercare
- Avoid vigorous exercise, saunas, and steam rooms for 24 to 48 hours after injectables.
- Avoid applying pressure to the treated area — including heavy facial massages, sleeping face-down, or aggressive skincare — for 2 weeks.
- Delay dental procedures for 2 weeks where possible, as dental anaesthesia and mouth manipulation can affect filler in the nasolabial area.
- Stay well hydrated and avoid alcohol for 24 hours to minimise bruising.
- Consistent sun protection (SPF 50 daily) supports long-term results regardless of the treatment chosen.
Review & Follow-Up
A two-week review is standard for filler and liquid PDO threadlift treatments. Swelling has fully resolved by this point and the result is settled — this is when any minor refinements can be made if clinically indicated. For biostimulators, a longer review window (6 to 12 weeks) is used because results develop progressively. HIFU reviews are typically scheduled at 3 months.
On expected results: Smile line treatment produces a softening and rebalancing of the fold, not complete elimination. The aesthetic goal is natural proportion, and most patients find that removing 50 to 70 percent of the visible depth of the fold produces a face that looks refreshed without looking treated. Attempts to erase the fold entirely almost always produce an overfilled appearance that other people can read as artificial, even if the patient cannot articulate why.
Individual response varies. Some patients need a single treatment; others benefit from staged sessions over several months. We do not promise specific outcomes, and we will tell you honestly if we believe a treatment is unlikely to meaningfully change your concern.
Smile Line Treatment Cost in Singapore
Treatment cost in Singapore varies substantially depending on the product, volume, and combination of treatments used — and no honest clinic can quote a precise figure without an assessment. What we can explain are the factors that drive the quote you will eventually receive.
Treatment Modality Chosen
Primary cost driverHA filler, Liquid PDO threadlift, HIFU, and biostimulators are priced differently because the products, consumables, and clinical time involved vary. Within each category, premium products typically cost more than standard products — though, as noted above, product choice is a clinical decision, not simply a price-tier decision.
Volume and Zones Treated
Clinical factorSmile line treatment is rarely just the fold. When we assess your face, we may recommend addressing the cheek, the marionette line, or the chin in the same session to produce a balanced outcome. Treating more zones costs more but often produces a more natural and longer-lasting result than focusing on the fold alone.
Number of Sessions
Long-term factorBiostimulator and HIFU protocols typically involve more than one session to reach the planned result. Filler is often require 2-3 sessions with maintenance every 18-24 months. Liquid PDO threadlift is usually a single session with maintenance every 12 to 18 months. When comparing costs, the per-session price is less meaningful than the total cost to reach and maintain the result.
Clinician Experience
Outcome factorInjector experience is the single most important determinant of injectable outcomes — and is reflected in pricing. A modestly priced treatment from an inexperienced injector often costs more in the long term, either in corrective treatment or in results that do not meet expectations. See our page on Dr Cherie Lau for her clinical background.
On pricing transparency: In accordance with Singapore's healthcare regulations, MIRAE does not advertise promotional discounts or package pricing for medical aesthetic treatments. Pricing is provided during the consultation after Dr Cherie Lau has assessed your concerns and formulated a treatment plan. The quote you receive reflects your specific plan — not a standard package applied to every patient.
Common Mistakes to Avoid
Over the years, certain patterns emerge in patients who come to us unhappy with smile line treatment done elsewhere. Understanding these in advance can help you avoid them.
- Treating the fold without treating the cheek. Putting filler directly into the fold without addressing mid-cheek volume loss creates a visible cushion above the lip that can appear more obvious than the original fold. This is the most common mistake in nasolabial treatment.
- Over-filling to try to erase the fold. The nasolabial fold is an anatomical boundary — it cannot be entirely eliminated on a normal face without distorting natural proportions. Chasing complete erasure produces unnatural results.
- Choosing the treatment before the diagnosis. Arriving at a consultation requesting "the filler I saw on social media" without discussing whether filler is actually the right treatment for your face is a common path to disappointment. The diagnosis should drive the treatment, not the other way around.
- Ignoring the rest of the face. Smile lines rarely occur in isolation. Treating them without considering the jawline, lips, chin, and general skin quality often produces a disproportionate result where the smile line area looks "corrected" against an otherwise ageing face.
- Expecting permanent results from a temporary treatment. HA filler is absorbed over time. Biostimulators stimulate collagen that eventually turns over. All injectable treatments require maintenance. If you are looking for a permanent solution, these are not it — and no honest clinician will tell you they are.
- Comparing prices without comparing plans. A quote for "smile line filler" from two different clinics may cover entirely different procedures — different products, different volumes, different zones treated. Always ask what is included before comparing.
Questions to Ask at Your Consultation
- Based on my face, what is the dominant cause of my smile lines — volume loss, descent, skin quality, or a combination?
- Would treating only the fold give me the result I want, or do you recommend treating adjacent areas (cheek, chin, jawline) as well?
- Which treatment do you recommend first — filler, liquid PDO threadlift, HIFU, biostimulator — and why that one for me specifically?
- What specific product do you plan to use, and why is it suited to my anatomy and concern?
- What realistic change should I expect, and when will the result be settled?
- What are the risks and possible complications, and how do you manage them if they occur?
- How long will the result last, and what does maintenance look like?
- Are there any non-injectable options I should consider first — skincare, sun protection, HIFU, or Morpheus8 — before proceeding to injectables?
- If my result is not what I expected at the review, what are the options for adjustment?
Key Takeaway
Smile lines — or nasolabial folds — are not a simple wrinkle that can be filled away. They are a structural change in the face driven by volume loss, tissue descent, skin laxity, and repetitive expression. The appropriate treatment depends on which cause is dominant in your face — which is why no responsible clinician will recommend a specific treatment without first assessing you. At MIRAE, Dr Cherie Lau's approach is grounded in facial balance and measured intervention: restoring proportion rather than eliminating the fold, and combining modalities where the clinical picture calls for it. Whether that is filler, liquid PDO threadlift, HIFU, biostimulators, or a combination, the plan is built around your face — not around a single product.
Medical Disclaimer: This article is written for general educational purposes and does not constitute medical advice, a diagnosis, or a recommendation for any specific treatment. Individual suitability for any treatment can only be determined following a thorough assessment by a licensed medical doctor. Results vary between individuals and cannot be guaranteed. Dermal fillers, biostimulators, Liquid PDO threads, and HIFU are medical procedures with risks as well as benefits — these should be discussed in detail at consultation.
Regulatory note: All dermal fillers, biostimulators, PDO threads, and medical devices used at MIRAE are HSA-registered and administered by Dr Cherie Lau, a medical doctor registered with the Singapore Medical Council and the Ministry of Health Singapore. This content is educational and is not intended to induce demand for treatment that is not clinically appropriate for the individual reader.
Further reading: Visit our smile lines concern page, HA dermal fillers page, and PDO liquid threadlift page for full treatment details.