The creases running from the sides of the nose to the corners of the mouth seem like they should respond to Botox. They appear when smiling, deepen with expression, and superficially resemble other dynamic wrinkles. But nasolabial folds differ fundamentally from forehead lines or crow’s feet. They result primarily from volume loss and skin descent, not muscle hyperactivity. Treating them with Botox targets the wrong mechanism and carries risks that make filler the standard approach for most patients.
The Misconception of Folding
The nasolabial fold forms at the junction between the mobile lip and cheek tissue and the fixed tissue of the midface. It is a boundary, not a crease in the traditional sense.
Young faces have nasolabial folds too. Look at a child’s face while they smile: the line is there. The difference is that young faces have abundant fat pads and elastic skin that fill out and smooth over when the expression ends.
Aging faces lose the fat pads that supported the cheek, particularly the malar fat pad that sits over the cheekbone. Without this volume, the cheek tissue descends, deepening the fold. The skin loses elasticity and cannot retract the way it once did.
The deepening is gravitational and structural, not primarily muscular. Treating the muscles that move the mouth does little to address falling volume or stretching skin.
Patients often assume their nasolabial folds result from smiling too much. This is rarely the case. The folds deepen because the face is losing internal architecture, not because facial expressions are excessive.
The LLSAN Muscle Target
There is one scenario where Botox contributes to nasolabial fold treatment: when the Levator Labii Superioris Alaeque Nasi (LLSAN) causes a bunching effect at the top of the fold.
The LLSAN elevates the upper lip and flares the nostril, particularly during the “snarl” expression. Some patients recruit this muscle heavily, creating a visible mound at the top of the nasolabial fold during certain expressions.
Treating the LLSAN relaxes this snarl component and softens the upper portion of the fold. The injection point lies approximately 1 cm lateral to the ala nasi and 3 cm superior to the lip line, at the Yonsei point identified in the aesthetic literature.
This treatment does not address the full length of the nasolabial fold. It targets only the superior bunching where the LLSAN inserts. Patients expecting complete nasolabial fold improvement from this limited treatment will be disappointed.
| Treatment | Target | Effect |
|---|---|---|
| LLSAN Botox | Upper fold bunching | Reduces snarl component |
| Cheek filler | Volume loss | Lifts and fills entire fold |
| Direct fold filler | Fold itself | Fills the crease directly |
The LLSAN treatment is an adjunct, not a standalone solution. Filler remains the primary intervention.
Risk of Smile Drop
The nasolabial region contains muscles critical for normal smiling. The zygomaticus major and minor pull the mouth corners upward and outward. The levator labii superioris elevates the upper lip.
Botox placed inaccurately can weaken these muscles, creating asymmetric smiling or a drooping upper lip. The effects are visible and distressing: one side of the smile moves less than the other, or the upper lip fails to elevate properly, exposing too little upper teeth.
The zygomaticus muscles lie dangerously close to any nasolabial injection. The toxin diffuses from the injection site, and even careful placement may affect adjacent structures. The zygomaticus originates on the cheekbone and crosses through the lateral midface on its way to the mouth corner, passing near typical injection zones.
Risk mitigation involves:
- Conservative dosing: lower doses diffuse less
- Precise placement: targeting LLSAN specifically, not the general nasolabial region
- Avoidance in high-risk patients: those with already-weak smiles or previous facial paralysis
The consequences of smile weakness are socially significant. Facial paralysis, even partial and temporary, affects how others perceive emotional expression. A patient whose smile is affected may feel self-conscious about basic social interactions until the Botox wears off.
When to Choose Botox Here
Despite the limitations, Botox has a role in nasolabial treatment for specific presentations:
The snarl pattern: Patients who elevate their upper lip aggressively, bunching tissue at the nostril base and creating a mound at the top of the nasolabial fold. LLSAN treatment reduces this specific component.
Gummy smile with nasolabial concerns: Some gummy smile patients also have pronounced nasolabial bunching from the same LLSAN overactivity. Treating both concerns with a single muscle target makes sense.
Combined treatment adjunct: Patients receiving filler may benefit from small amounts of Botox to reduce dynamic motion that would otherwise fight against the filler. The filler addresses volume; the Botox reduces movement that would displace it.
For most patients seeking nasolabial fold improvement, Botox is not the answer. The fold results from structural changes that require structural solutions.
Why Filler is the Gold Standard
Dermal filler addresses the actual cause of nasolabial deepening: volume loss. Hyaluronic acid or other fillers restore the lost padding that once supported the cheek tissue and prevented the fold from deepening.
Filler can be placed in the cheek to lift the tissues that have descended into the fold. This indirect approach treats the cause rather than the symptom.
Filler can also be placed directly in the fold to soften the crease itself. This direct approach treats the symptom and provides immediate visible improvement.
The combination of cheek volumization and direct fold treatment produces comprehensive results that Botox cannot match. The structure is restored, the crease is filled, and the improvement persists as long as the filler lasts.
Filler duration in the nasolabial folds varies by product and individual metabolism: typically 9-18 months for hyaluronic acid products. Retreatment maintains the result, and many patients find they need less product over time as the treated tissue maintains some of the repositioning.
Managing Patient Expectations
Patients seeking nasolabial fold treatment need clear communication about what Botox can and cannot achieve.
Can achieve: Softening of upper fold bunching from LLSAN activity, modest improvement in snarl-related deepening, adjunctive support for filler treatment.
Cannot achieve: Significant improvement in established nasolabial folds, correction of volume loss, lifting of descended cheek tissue, elimination of the fold itself.
The honest answer for most nasolabial fold complaints: “Botox is probably not your primary solution. Filler addresses the volume loss causing your folds. We might add a small amount of Botox if you have significant snarl activity, but filler does the heavy lifting.”
Setting this expectation prevents the frustration of treating the wrong problem with the wrong tool. Patients who receive Botox expecting filler-like results blame the injector, the product, or both. Patients who understand the mechanism and receive appropriate treatment are more satisfied with realistic outcomes.
Sources:
- Yonsei point and LLSAN anatomy: Journal of Cosmetic Dermatology, “Anatomical Considerations for Botulinum Toxin in Nasolabial Region”
- Nasolabial fold pathophysiology: Aesthetic Plastic Surgery, “The Nasolabial Fold: A Morphologic and Histologic Reappraisal”
- Zygomaticus injection complications: Plastic and Reconstructive Surgery, “Smile Asymmetry Following Perioral Botulinum Toxin”