Gummy Smile and Botox: It Only Works for One of the Four Causes
Reviewed for medical accuracy against our Medical Review Board · Last updated 27 August 2026
Part of Botox by Facial Area
A gummy smile has four possible causes: a muscle that lifts your upper lip too far, the shape of your upper jaw, the position of your teeth, and how much volume your lip has. Botox treats exactly one of them. If your gum shows because of your bone or your teeth, no dose and no injector will change it, and the honest answer is a dentist or an oral surgeon rather than a med spa.
Establishing which cause you have is the entire consultation, and it is skipped constantly. The word "gummy" appears zero times in the BOTOX label, as does "gingival", as does "levator labii", the muscle this treatment targets. There is no approved dose here, and there is one genuinely useful randomized study whose most important feature is what it did not measure.
1. Four causes, one of which responds
"Gummy smile", clinically excessive gingival display, usually means more than about 2 to 3 millimetres of gum visible above the upper teeth when you smile fully. The published account of why it happens lists four contributors: excessive muscle activity, variations in the upper jaw bone, dental malformations, and smaller lip volume.
Those four have almost nothing in common except the appearance they produce:
| Cause | How to recognise it | Does Botox help? |
|---|---|---|
| The lip-lifting muscle travels too far | Little gum at rest or on a small smile, a lot on a full one. The gap between your relaxed and maximum smile is dramatic | Yes. This is the treatable cause |
| Vertical maxillary excess, the shape of the upper jaw | Gum shows even on a moderate smile, and often a long-looking midface. Usually lifelong rather than new | No. This is skeletal. Orthodontics or surgery |
| Tooth position or size, including short clinical crowns | Teeth look short relative to the gum, or the gum line is uneven | No. A dentist or periodontist |
| A short or thin upper lip | Little lip visible, and the lip looks thin rather than mobile | Partly, and filler may be more appropriate |
The rough self-test: compare your relaxed mouth with your biggest smile in a mirror. If the amount of gum changes dramatically between the two, muscle is doing the work and a neurotoxin has something to relax. If gum is visible even on a small or moderate smile, something structural is contributing and you should be assessed by a dentist before anyone injects you.
This is the one page on the site where the right answer is often "go to a dentist". Excessive gingival display from vertical maxillary excess or short clinical crowns is a dental and skeletal problem. Botox cannot move bone or lengthen a tooth, and a clinic that does not raise the possibility has not assessed you.
2. The muscle, and how much lift is normal
The muscle principally responsible is the levator labii superioris alaeque nasi, usually abbreviated LLSAN. It runs from beside the nose down to the upper lip, and it lifts the lip and flares the nostril. Other elevators contribute, but the LLSAN is the one targeted in this treatment.
The mechanism is limitation rather than repositioning. Relaxing the LLSAN means the lip travels less far upward at full smile, so less gum is exposed. Nothing is lowered, added or lifted. Your smile simply has a slightly shorter range at the top of its travel.
That framing matters because it tells you what the treatment costs you: some of the height of your smile. Done well, that is imperceptible and only removes the excess. Done heavily, it is the difference between a warm smile and a restrained one, and there is no reversal agent. This is why the doses here are tiny and why conservative is genuinely the right call rather than a hedge.
3. What the label says, and its six mentions of "smile"
We searched the complete BOTOX Cosmetic prescribing information effective 18 October 2024, nearly 136,000 characters. "Gummy": zero. "Gingival": zero. "Levator labii": zero. "Lip": zero. Meanwhile glabellar lines appear 64 times, platysma bands 50, forehead lines 43 and lateral canthal lines 35, each with a labelled dose and an injection diagram.
There is one detail worth reporting because it is easy to misconstrue. The word "smile" does appear in the label, six times. Every single occurrence is the phrase "maximum smile", and it is there because smiling is the posture used to grade crow's feet severity in the lateral canthal lines trials. Subjects had to have moderate to severe lateral canthal lines "at maximum smile at baseline".
So the label engages with your smile only as a measuring condition for a different area. It never treats a smile as something to modify. If you see a clinic imply that Botox is approved for anything to do with smiles, that is where the confusion comes from, and it is wrong.
4. The randomized study, and what it cannot tell you
Unusually for an off-label facial area, randomized evidence exists. A 2026 study in the Journal of Dental Research, Dental Clinics, Dental Prospects enrolled 30 adults aged 18 to 65 with more than 2 mm of gingival exposure on smiling, and randomly assigned them to three groups: botulinum toxin alone (10 people), hyaluronic acid filler alone (10 people), or both (10 people). Lip pressure was measured objectively at baseline and at 15, 30, 90 and 180 days. Quality of life was assessed with the Glasgow Benefit Inventory.
The findings: all groups showed statistically significant changes in lip pressure over time, and all three improved quality of life, with the combination treatment "standing out".
Now the part that matters most, and the reason to be careful with how this study gets quoted. The paper explicitly states that "intergroup comparisons across time intervals were not assessed". The three arms were never statistically compared against each other over time. Combined with ten people per arm, that means:
- It supports the idea that these treatments do something measurable and that patients feel better afterward.
- It cannot tell you that toxin beats filler, that filler beats toxin, or that the combination beats either. The impression that combined treatment won is an observation, not a statistically tested result.
- Ten per arm is very small. Treat it as encouraging rather than decisive.
If a clinic cites research showing the combination is superior, this is almost certainly the study, and it does not show that. Our Botox versus fillers guide covers how to think about choosing between them when the evidence does not settle it.
5. Units, and why this is the least forgiving small dose
There is no labelled dose. In practice this is one of the smallest treatments in aesthetics: commonly 2 to 3 units per side, so roughly 2 to 6 units in total, consistent with our units guide.
Of all the small-dose areas, this is the one where going slightly over has the most visible cost. Over-treatment does not simply under-deliver, it produces a stiff or oddly flat upper lip and a smile that reads as reserved. Because the muscles that lift your lip are also the muscles that make a smile look warm, the failure mode is a change in how your expression is perceived, which is harder to live with for three months than a line you wanted softened.
The sensible approach, and what good injectors do, is to start low and add at a review two to three weeks later if the effect is insufficient. You can always add. You cannot remove.
6. Not a lip flip, whatever the price list says
These two treatments are constantly conflated, often on the same price list, and they are different procedures targeting different muscles for different goals.
| Gummy smile treatment | Lip flip | |
|---|---|---|
| Muscle targeted | Levator labii superioris alaeque nasi, beside the nose | Orbicularis oris, the ring muscle around the mouth |
| Goal | Reduce how far the upper lip rises, so less gum shows | Roll the upper lip slightly outward so more pink shows |
| What it looks like | Less gum at full smile | A marginally fuller-looking upper lip without filler |
If a gummy smile is what bothers you, say that specifically rather than asking for a lip flip. Our lip flip page covers that treatment on its own terms, including how short-lived it is.
7. Lip inversion, and the overdosing trap
A recognised accompaniment to a gummy smile is lip inversion, where the upper lip rolls inward and shows less pink. It can be present alongside the excessive gum display, and it changes the calculation in a way worth knowing about.
A 2026 case report in Cureus describes correcting the inversion with botulinum toxin alongside the gummy smile treatment, and makes a point that is directly useful to a patient: doing so "can obviate the need for overdosing and the use of lip fillers". In other words, if the lip is rolling inward as well as rising too far, chasing the appearance by simply increasing the dose aimed at the elevators is the wrong move, and addressing the inversion separately can avoid both a heavier dose and a filler purchase.
This is a single case report, which is the weakest form of clinical evidence, so it is a mechanism worth asking about rather than a protocol to request. But it names the trap accurately: when the first treatment does not fully achieve the look, the tempting response is more units, and more units in this area is where the stiff-lip outcomes come from.
8. What can go wrong
The risks here are all about the smile, because the target muscles are the smile. The recognised problems are a stiff or flattened upper lip, an asymmetric smile if one side receives more effect than the other, difficulty with precise sounds involving the lips, and a smile that feels restrained to you even when others do not notice.
Two structural reasons this area is unforgiving. The muscles are small and immediately adjacent, so a couple of millimetres of diffusion changes which muscle is affected. And the LLSAN sits right beside the nasalis, which is why gummy smile treatment and bunny line treatment can influence one another, and why the same injector should know about both.
All of it is temporary and resolves as the drug wears off, on the timeline in our how long Botox lasts page. Given the stakes are your smile for a few months, this is an area to have treated by somebody who does it regularly. Confirming who is treating you and what licence they hold takes two minutes with our verification guide.
9. What it costs at real published rates
At 2 to 6 units this is the smallest neurotoxin treatment on the site, and the cheapest. The figures use per-unit rates published by clinics in the cities we cover.
| City | Published rate per unit | 2 to 6 units |
|---|---|---|
| Atlanta, GA | $9 to $15 | $18 to $90 |
| Austin, TX | $11 to $13.5 | $22 to $81 |
| Charleston, SC | $9.99 to $13 | $20 to $78 |
| Charlotte, NC | $9 to $15 | $18 to $90 |
| Chicago, IL | $9 to $15 | $18 to $90 |
| Denver, CO | $10 to $16 | $20 to $96 |
| Houston, TX | $12 to $14.5 | $24 to $87 |
| Las Vegas, NV | $10 to $16 | $20 to $96 |
| Nashville, TN | $10 to $14 | $20 to $84 |
| Philadelphia, PA | $10 to $15 | $20 to $90 |
| Phoenix, AZ | $9.99 to $13 | $20 to $78 |
| Raleigh, NC | $13 to $14 | $26 to $84 |
| Salt Lake City, UT | $9.8 to $14 | $20 to $84 |
| San Antonio, TX | $10.5 to $12.5 | $21 to $75 |
| San Diego, CA | $10 to $16 | $20 to $96 |
| Scottsdale, AZ | $10.5 to $13.5 | $21 to $81 |
| Tampa, FL | $10 to $18 | $20 to $108 |
Those figures are lower than almost every clinic minimum spend, so this will be quoted as part of something larger or subject to a minimum. Ask for the itemised price and ask what the minimum is. Also ask about the review appointment: if the plan is to start low and add, find out whether the top-up is included or charged separately, because that changes the real cost materially.
10. What to ask before you agree
Six questions for a gummy smile consultation
- Is my gum showing because of muscle, bone, teeth or lip volume? The first and most important question. If the answer does not distinguish between them, you have not been assessed. Botox addresses one of the four.
- How much gum shows at rest, and how much at maximum smile? A big difference means muscle. Gum visible on a moderate smile points to something structural.
- Should I see a dentist or orthodontist first? An honest injector will say yes when the cause looks skeletal or dental. Willingness to raise it is a good sign about everything else.
- What dose per side, and will you start low and review? Expect 2 to 3 units a side. Starting low with a review at two to three weeks is the right approach because nothing can be undone.
- Is the review or top-up included in this price? At these unit counts the review policy affects the real cost more than the per-unit rate does.
- What happens to my smile if this is slightly too much? A specific answer about a flat or stiff upper lip and a timeline for recovery is what you want. There is no reversal agent.
The reason to be careful here is not that the treatment is dangerous. It is that the thing being adjusted is your smile, the adjustment is not reversible for a few months, and a good proportion of the people searching for this treatment have a cause it cannot address. Settle the cause first. If it is muscular, this is a small, cheap, effective treatment that works well at a conservative dose.
Every area Botox treats, and what each one takes
Botox is not one treatment, it is eight or so, and the dose ranges by a factor of thirty between the smallest and the largest. 4 of these areas are on the FDA label; the rest are off-label, which is legal and common but means the dose comes from clinical practice rather than from a registration trial.
| Area | Typical dose | FDA status |
|---|---|---|
| Frown lines (glabella) | 20 units | FDA approved |
| Forehead lines | 20 units, with the glabella | FDA approved |
| Crow's feet | 24 units | FDA approved |
| Neck and platysmal bands | 26 to 36 units | FDA approved |
| Brow lift | 4 to 12 units | Off-label |
| Lip flip | 2 to 6 units | Off-label |
| Masseter (jaw slimming) | 40 to 60 units | Off-label |
| Under the eyes | 1 to 4 units per side | Off-label |
| Bunny lines (nose) | 2 to 5 units per side | Off-label |
| Gummy smile (you are here) | 2 to 3 units per side | Off-label |
| Marionette lines | 2 to 8 units per side | Off-label |
Units are not comparable between brands, so these are Botox units. Full ranges per area are in the units guide and calculator.
Frequently asked questions
Can Botox fix a gummy smile?
How many units of Botox for a gummy smile?
Is a gummy smile treatment the same as a lip flip?
Is Botox or filler better for a gummy smile?
Is Botox approved for gummy smile?
What happens if too much Botox is used on a gummy smile?
Know the count before the quote. The unit count is half the bill, and a low per-unit rate recovered by a high unit count is the commonest way a deal is not one. How to tell.
Deciding which area, not how many units? Botox by facial area covers what each zone actually achieves, which four are FDA approved, and the things Botox cannot fix at all.
