Botox injections targeting the levator labii superioris and its neighboring muscles are one of the most common nonsurgical treatments for a “gummy smile,” where too much gum tissue shows above the upper teeth when you smile. The procedure typically involves just a few units of botulinum toxin placed near the nose on each side, and it can reduce visible gum tissue by several millimeters within a couple of weeks. The treatment is quick, minimally invasive, and well-studied for this specific use, but it comes with tradeoffs worth understanding before you book an appointment.
What the Levator Labii Superioris Does
The levator labii superioris is a thin muscle that runs alongside the nose, originating near the lower rim of the eye socket and inserting into the upper lip. Its main job is pulling the upper lip upward and outward. It also helps produce facial expressions like disgust and sadness and plays a role in nasal flaring.1PubMed. Anatomy, Head and Neck, Levator Labii Superioris Muscle It does not work alone. A closely related muscle called the levator labii superioris alaeque nasi runs alongside it in two layers, superficial and deep, and inserts between other muscles of the mouth.2PubMed. New anatomical insight of the levator labii superioris alaeque nasi and the transverse part of the nasalis The zygomaticus minor, which sits just lateral to it, also contributes to pulling the lip upward.
When these three muscles are overactive, they can hoist the upper lip higher than average during a smile, exposing a wide band of gum tissue above the teeth. Clinicians call this “excessive gingival display,” and it is one of the most common reasons people seek cosmetic correction. When the cause is muscular rather than skeletal (short upper jaw, overgrown gum tissue, or teeth that have not fully erupted), weakening those lip-elevator muscles with botulinum toxin is a straightforward fix.3PubMed. Botulinum toxin type A in the treatment of excessive gingival display
How Botox Weakens the Muscle
Botulinum toxin type A works by blocking the release of a chemical messenger called acetylcholine at the junction where nerves meet muscle fibers. Without acetylcholine, the muscle cannot contract at full strength. The toxin binds to nerve terminals, gets pulled inside, and then clips a protein that nerve cells need to release their chemical signals.4PubMed Central. Botox (onabotulinumtoxinA) mechanism of action The muscle does not become paralyzed in the way you might imagine. Instead, it weakens enough that the upper lip no longer rides as high when you smile. Over months, the nerve terminals gradually sprout new connections and restore signaling, which is why the effect wears off.
This same mechanism underlies every cosmetic and medical use of Botox, from forehead wrinkles to chronic migraines. What makes the levator labii superioris area distinctive is that the muscles are small, the doses are low, and the margin for error is tight. Putting too much toxin in the wrong spot near the mouth can temporarily weaken nearby muscles that control lip seal and speech. The doses used around the midface tend to be lower than those used in the upper face for exactly this reason.5PubMed. Aesthetic botulinum A toxin in the mid and lower face and neck
Where the Injection Goes
The most widely studied injection strategy for gummy smile correction targets a landmark called the Yonsei point, named after the Korean university where it was developed. This is a spot lateral to the nose where the levator labii superioris, the levator labii superioris alaeque nasi, and the zygomaticus minor all converge in a small triangular zone. A single injection at this point can reach all three muscles at once, rather than requiring separate injections into each one.6PubMed Central. Establishing standards for Yonsei point in a White South African population for the treatment of gummy smile
To find it, practitioners draw an imaginary vertical line from the edge of the nostril and then measure about one centimeter to the side, intersecting with a horizontal line roughly three centimeters above the corner of the mouth. The injection is placed just under the skin at that spot, typically with a fine 30-gauge needle.7Journal of Craniofacial Surgery. The Yonsei Point: A Precision Approach to Gummy Smile Correction With Botulinum Neurotoxin In a randomized trial comparing the Yonsei point approach to injections placed directly into the levator labii superioris alaeque nasi, both sides received a total of 6 units, split as 3 units per side.8PubMed. Application of Botulinum Toxin at the Yonsei Point for the Treatment of Gummy Smile: A Randomized Controlled Trial
The Yonsei point is not the only strategy. Some practitioners prefer a multi-point approach, placing smaller doses into each muscle individually. A third strategy, sometimes called a “lip flip,” targets the orbicularis oris muscle along the lip border to roll the upper lip outward slightly rather than directly weakening the elevators. A review of the literature identified all three strategies as effective, though standardized protocols are still lacking, with dosing ranging from about 2 to 5 units per injection site depending on the severity of gum exposure.9FACE. Cosmetic Management of Gummy Smiles with Botulinum Toxin A: A Review
How Much Improvement to Expect
Across multiple studies, botulinum toxin consistently reduces the amount of visible gum by about 3 to 5 millimeters.10FACE. Cosmetic Management of Gummy Smiles with Botulinum Toxin A: A Review That might not sound like much, but a few millimeters make a surprisingly large visual difference in how a smile looks. In one study, the average gingival display dropped from roughly 5 millimeters at baseline to essentially zero at two weeks after injection, though this dramatic a result may not hold for everyone.11PubMed Central. A Standardized Technique for Gummy Smile Treatment Using Repeated Botulinum Toxins: A 1-year Follow-up Study
The response is not identical for everyone. A prospective study found that women tended to get more correction than men with the same dose. The researchers developed a prediction model showing that a woman with less than about 5 millimeters of baseline gum exposure could expect to end up with roughly 0.3 to 3 millimeters after treatment, while a woman with 6 millimeters or more of baseline exposure might still show 3 to nearly 9 millimeters afterward.12Aesthetic Surgery Journal. Individual Factors of Botulinum Type A in Treatment of Gummy Smile: A Prospective Study The takeaway: if your gummy smile is moderate, Botox alone may bring it into a comfortable range. If it is severe, you may see improvement but not full resolution, and additional or alternative treatments might be worth discussing.
How Long the Effect Lasts
This is one of the most important practical details, and the evidence is consistent. You will typically see the effect begin within a week or two after injection, with peak results at about two weeks.13PubMed Central. Clinical and electromyographic evaluation of botulinum toxin type A in the treatment of gummy smile: A prospective clinical study After that, the muscle gradually regains strength. Most studies report that results remain noticeable for about three to four months, with the gummy smile returning to baseline by roughly five to six months.14PubMed Central. To evaluate the effect and longevity of Botulinum toxin type A (Botox) in the management of gummy smile – A longitudinal study upto 4 years follow-up A systematic review described the effective window as roughly 12 to 24 weeks, depending on the dose and severity of the original gum display.15PubMed. Dose and injection site of botulinum toxin type A for gummy smile management: A systematic review and bibliometric analysis
One controlled trial tracked patients for 25 weeks across two groups receiving injections at different numbers of points. Interestingly, using more injection sites prolonged how long patients stayed satisfied (about 21 weeks for the multi-point group versus 16 weeks for fewer injection points), but did not increase the degree of gum reduction at any single time point.16Aesthetic Surgery Journal. Botulinum Toxin A in the Management of a Gummy Smile: A Clinical Controlled Preliminary Study This suggests that spreading the dose across more sites may gently extend how long the correction holds, even if it does not make the initial result more dramatic.
Because the effect is temporary, most people who want to maintain results need to return for retreatment roughly every four to six months.17PubMed Central. An Approach for Gummy Smile Treatment Using Botulinum Toxin A: A Narrative Review of the Literature This ongoing commitment is the main practical drawback compared to a surgical approach.
Side Effects and Safety
Reported complications from these injections are rare and almost always temporary. The most common issues are mild asymmetry in the smile and slight weakness of the upper lip. In one study of 30 patients treated based on a gingival exposure area protocol, two patients showed mild side effects that were corrected with small additional doses of toxin.18PubMed. Gummy smile and botulinum toxin: a new approach based on the gingival exposure area A broader review described complications as “rare and transient,” typically limited to mild asymmetry and lip weakness.19FACE. Cosmetic Management of Gummy Smiles with Botulinum Toxin A: A Review
The biggest safety concern is not a severe reaction but an unwanted cosmetic outcome. If the toxin diffuses too far from the injection site, it can temporarily affect muscles responsible for lip seal, making it harder to drink through a straw or pronounce certain sounds. Caution around the perioral area is standard practice to avoid what clinicians describe as an “incompetent mouth.”20PubMed. Aesthetic botulinum A toxin in the mid and lower face and neck These effects resolve on their own as the toxin wears off, usually within a few weeks if they occur at all. Choosing a practitioner experienced with midface injections matters more here than in many other Botox applications precisely because the muscles are so close together and so functionally important.
Botox Versus Surgery for Gummy Smiles
The main surgical alternative is lip repositioning, a procedure where the surgeon restricts how far upward the lip can travel by modifying the tissue attachment between the lip and the gum line. One study comparing lip repositioning alone with lip repositioning plus Botox found that adding Botox provided a significantly greater improvement at 3 months. By 12 months, however, the difference between the two groups was no longer significant, and the surgical results held steady regardless of whether Botox was added.21PubMed Central. Comparison of lip repositioning and lip repositioning with botulinum toxin application in gummy smile treatment
This pattern highlights the fundamental tradeoff: Botox gives you fast, noticeable improvement with zero downtime and no incisions, but you will need to keep coming back. Surgery involves recovery time and carries the usual risks of any oral procedure, but the results are durable. For someone who wants to “test drive” a reduced gummy smile before committing to anything permanent, Botox serves as a low-risk preview of what a corrected smile might look like.
Combining Botox With Other Treatments
Gummy smiles often have more than one contributing factor. The muscles might be overactive, but the teeth could also be slightly short, or the lip itself could be thin. Increasingly, practitioners are combining multiple treatments to address all of these dimensions at once. One approach dubbed the “combo technique” pairs Botox with esthetic crown lengthening (a dental procedure that exposes more tooth and removes excess gum tissue) and hyaluronic acid lip filler. This combination allows lower Botox doses while achieving stable cosmetic results and high patient satisfaction.22Journal of Esthetic and Restorative Dentistry. The Combo Strategy: Triple Approach for Gummy Smile—18‐Month Case Series
Hyaluronic acid filler on its own has also been studied as an alternative to Botox for gummy smiles. The idea is that injecting filler into the upper lip adds volume and weight, which physically limits how high the lip can rise. A head-to-head comparison found that while Botox gave quicker initial improvements, hyaluronic filler produced more consistent results over time, and patients in the filler group reported higher satisfaction scores across follow-up visits.23PubMed Central. Comparison of Effectiveness, Duration, and Patient’s Satisfaction of Botulinum Toxin A and Hyaluronic Filler in the Treatment of Gummy Smile: An in Vivo Study The filler approach, sometimes called “myo modulation,” is minimally invasive and offers a different risk-benefit profile since it does not weaken the muscles at all.24PubMed Central. Botulinum Toxin Type A and Hyaluronic Acid Dermal Fillers in Dentistry: A Systematic Review of Clinical Application and Indications
Uses Beyond the Gummy Smile
While cosmetic gummy smile correction is the most frequently discussed reason for injecting the levator labii superioris area, the same technique has therapeutic applications. One of the more significant is managing facial asymmetry after facial nerve palsy, a condition where damage to the facial nerve (from Bell’s palsy, surgery, or trauma) leaves one side of the face moving differently from the other. On the unaffected side, the muscles often become overactive as they compensate. Injecting botulinum toxin into the levator labii superioris, its alaeque nasi neighbor, and the zygomaticus muscles on the overactive side helps rebalance the face, reducing the deepening of the nasolabial fold and the asymmetric pull during smiling or speaking.25PubMed Central. Efficacy and Short-term Durability of Combined Botulinum Toxin Type A and Rehabilitation for Chronic Facial Asymmetry After Facial Nerve Palsy
This is a genuinely different clinical scenario from cosmetic gummy smile treatment. The goal is not to reduce gum exposure but to even out the visual appearance of the face at rest and during expression. The muscles targeted overlap substantially with those in gummy smile protocols, but the dosing strategy and placement differ because the objective is symmetry rather than simple reduction of lip elevation.
Emerging Precision Tools
One of the ongoing challenges with Botox in the midface is that everyone’s anatomy varies. The muscles are layered, they overlap, and their exact positions shift from person to person. A growing body of research is exploring ultrasound guidance as a way to visualize the muscles in real time during injection. This allows the practitioner to see exactly where the needle tip sits relative to the muscle fibers and nearby blood vessels, potentially reducing the chance of unintended spread to adjacent muscles and improving how precisely the toxin lands.26PubMed. Sonoanatomy of injecting botulinum neurotoxin into the facial muscles This is still more common in research settings than in everyday cosmetic clinics, but it represents where the field is heading, especially for complex cases where standard landmark-based approaches have not given a satisfactory result.
The broader picture for anyone considering this procedure is that the evidence base is solid for short-term gummy smile reduction, the risks are low when the injection is done by someone who understands the anatomy, and the main limitation is simply that it does not last. Whether that tradeoff works for you depends on how bothered you are by the gummy smile, how comfortable you are with repeat visits, and whether a longer-lasting option like surgery or filler might better fit your goals.