A "lip flip" is an off-label injection of a few units of botulinum toxin (Botox, Dysport, Xeomin, Jeuveau, or Daxxify) into the orbicularis oris — the donut-shaped muscle that circles your mouth. As that muscle relaxes, the upper lip rolls gently outward (everts), so it looks fuller without adding any volume. A typical treatment uses about 4–6 units in the upper lip (sometimes 1–2 more in the lower), takes 10–20 minutes, costs roughly $80–500 (usually a few hundred dollars because so few units are used), and lasts about 2–3 months — shorter than forehead Botox because the mouth moves constantly.
The headline distinctions patients miss: a lip flip changes shape, while lip filler adds volume; a lip flip cannot be reversed (you wait it out), unlike hyaluronic-acid filler, which an enzyme can dissolve; and if it is overdone it can cause drooling, trouble speaking or using a straw, and an asymmetric smile. No botulinum toxin is FDA-approved for a lip flip — it is an off-label use that carries the same class boxed warning about distant spread of toxin effect as every approved indication. This article walks the mechanism, the dosing math, the gummy-smile variant, what goes wrong, and how to decide between a flip and filler.
What a Botox lip flip actually is: the orbicularis oris mechanism
The orbicularis oris is the sphincter-like muscle that closes and purses your lips. It has two layers: a deep layer that squeeze the lips together, and superficial intrinsic fibers that attach into the skin of the lip and pull it inward and downward when they contract. As these intrinsic fibers become overactive (or simply stay tense), the upper lip can roll inward, making it look thin and lengthening the distance between the nose and the red part of the lip.
A lip flip targets those superficial intrinsic fibers at the vermilion border — the sharp color boundary where the pink lip meets the surrounding skin. Injected precisely there in tiny doses, the toxin relaxes the fibers that were pulling the lip inward. With the pull released, the lip everts (rolls outward) so more of the pink vermilion shows. A 2026 peer-reviewed study in Aesthetic Plastic Surgery concluded that the lip flip enhances upper-lip projection "primarily by neuromuscular modulation rather than volumetric augmentation" — which is the precise rebuttal to the common misconception that a lip flip "adds a little volume." It does not. It changes the resting posture of the lip so more of the lip you already have is visible.
That mechanism has three practical consequences:
- You must already have some lip to flip. If your upper lip is genuinely very thin, there is little vermilion to roll outward, and the result is subtle. Filler is the better tool when the problem is absent volume.
- The effect is dynamic. Because it works through muscle, the result depends on how your lip naturally moves. People with a thin lip that rolls inward at rest see the most dramatic change.
- It complements, rather than competes with, filler. Clinicians routinely combine a small flip (for shape and eversion) with a small amount of hyaluronic-acid filler (for volume), because they solve different problems. This pairing is covered in the lip flip vs filler section below.
How many units does a lip flip take, what does it cost, and how long does it last?
Units
Published clinical sources converge on a small dose, though they describe it differently. The Cleveland Clinic's treatment page places a typical flip at about 2–4 units in the upper lip and about 2 units in the lower lip; injector-guidance and clinic sources generally cluster around 4–6 units for the upper lip. There is no single "correct" number because the dose is tailored to lip thickness and muscle strength, but the range is narrow — this is a low-dose, superficial technique. Going higher does not produce "more flip"; it produces dysfunction (see the risk section).
For a gummy smile, the target muscle is entirely different (the levator labii superioris alaeque nasi, or LLSAN), and the dosing is separate — covered next.
Cost
Because the unit count is so low, the per-session price is correspondingly modest. Clinic cost pages place a lip flip at roughly $80–500, most commonly a few hundred dollars, at typical per-unit pricing ($10–20 per unit). Compare that with hyaluronic-acid lip filler, which commonly runs $500–1,000+ per syringe — so the lip flip is cheaper per session. But that comparison hides the real cost over a year, which is the comparison that actually matters (see the table below). For the unit-pricing framework behind these numbers, see our guide to how Botox is priced per unit versus by area.
| Botox lip flip | Hyaluronic-acid lip filler | |
|---|---|---|
| Typical per-session cost | ~$80–500 (few units) | ~$500–1,000+ per syringe |
| Sessions per year | ~4–6 (every ~2–3 months) | ~1–2 (lasts 6–12 months) |
| Approximate year-one cost | ~$300–1,500 (plus consultations) | ~$500–2,000+ |
| Adds volume? | No — shape only | Yes |
| Reversible? | No | Yes (hyaluronidase) |
| Onset | ~3–7 days | Immediate (settles over 1–2 weeks) |
How long it lasts, and why it is shorter than forehead Botox
Here is where med-spa pages disagree loudly and confuse patients: one will say a lip flip lasts 4–6 weeks, another 3–4 months, another 2–5 months. The reconciliation is straightforward. The cosmetic duration of a perioral toxin treatment runs about 2–3 months in practice; the Cleveland Clinic gives a wider envelope of "2–5 months." The reason the mouth wears off faster than the forehead (where Botox commonly lasts 3–4 months) is mechanical: the orbicularis oris is in near-constant motion whenever you talk, eat, drink, and smile. That repeated contraction metabolizes and clears the toxin faster than a relatively static muscle like the frontalis. So while a lip flip is cheap per session, it requires more sessions per year than forehead Botox, and the year-one cost gap with filler narrows considerably. For the duration framework on the filler side, see our article on how long lip filler lasts versus a lip flip.
Lip flip or lip filler: which do you need, and can you combine them?
The decision is not "which is better." The two address different anatomy:
- Choose filler when the problem is missing volume — a genuinely thin lip, age-related deflation, asymmetry from one side being smaller, or a desire for noticeably plumper lips.
- Choose a lip flip when the problem is shape or posture — a lip that looks thin because it rolls inward at rest, a long upper-lip-to-nose distance, or a "gummy" smile where too much gum shows (then the toxin targets the LLSAN, below).
- Combine them when you want both. A small amount of filler restores volume while a small flip everts the border, so the filler sits on an outward-rolled lip rather than a tucked-in one. Done conservatively, this is the canonical "natural-looking" result — see our article on natural-looking neuromodulator results for the dosing philosophy behind that look.
The cost-per-syringe math on the filler side, including what drives price up or down, is in our lip filler cost-per-syringe guide.
Gummy smile Botox: the LLSAN muscle, dosing, and who it helps
A "gummy smile" — formally, excessive gingival display — is when more than a few millimeters of upper gum shows on full smile. It has several causes (short upper lip, jaw position, tooth length, orthodontic factors), but one common driver is hyperactivity of the levator labii superioris alaeque nasi (LLSAN), a small muscle in the cheek that elevates the upper lip. When the LLSAN is overactive, it lifts the lip too far during a smile.
For the LLSAN-driven gummy smile, botulinum toxin is a recognized off-label option, and the anatomy is entirely different from the orbicularis-oris lip flip. Clinical references (the Plastic Surgery Key gummy-smile chapter by Sieber and Kenkel, and injector-guidance sources) place a typical starting dose at about 2–4 units per side into the LLSAN. A 2024 dose-finding study in Toxicon found that 2–3 units per side can be sufficient and that increasing to 5 units or higher brought more adverse effects without proportional benefit. A 2023 review (Fatani et al., PMC) describes Polo's classic 2.5-unit LLSAN injection technique. The practical takeaway: gummy-smile dosing is small, conservative, and bilateral.
Important boundaries:
- A toxin-treated gummy smile lasts roughly the same ~2–3 months as a lip flip, for the same motion-related reason.
- If the gummy smile is caused by skeletal or dental anatomy rather than muscle overactivity, toxin will do little — an orthodontic or surgical assessment is the right referral, not a higher toxin dose.
- Some patients have a gummy smile and a thin lip; then an LLSAN treatment and an orbicularis-oris flip are different injections at the same visit.
What goes wrong: drooling, speech, and straw trouble — and why you can't reverse it
Because the orbicularis oris is the muscle you use to seal your mouth, over-relaxing it produces exactly the dysfunctions you would predict. The Cleveland Clinic and clinic complication lists converge on a consistent set:
- Drooling and difficulty keeping food or drink in the mouth, because the lip cannot seal cleanly.
- Trouble speaking clearly or pronouncing certain sounds, particularly "p," "b," and "m."
- Inability to use a straw or to whistle, because pursing is weakened.
- An asymmetric smile if the dose is uneven or if toxin spreads unevenly to one side.
- A flattened or "heavy" feeling in the lip that some patients find unpleasant even when it is not strictly a malfunction.
Two things make these mistakes costly. First, botulinum toxin cannot be reversed. Unlike hyaluronic-acid filler, which the enzyme hyaluronidase can dissolve within hours, there is no antidote that turns the toxin off. You wait — typically several weeks to a few months — for the effect to wear off. That irreversibility is the single most important reason to choose an experienced injector and to dose conservatively. Second, the difference between a good flip and a dysfunctional one is often one or two units and a few millimeters of placement. A practitioner who treats the perioral area regularly knows how to titrate; one who does it occasionally is more likely to overshoot. Choosing a qualified injector is covered in our how to choose an injector guide.
The same logic applies to the gummy-smile LLSAN injection: overshooting the dose can drop the upper lip too far and create an asymmetric or "floppy" smile that, again, cannot be reversed until the toxin wears off. This is precisely why the Toxicon dose-finding data — 2–3 units sufficient, more brings harm — matters.
Is the lip flip FDA-approved? Off-label use and the boxed warning
This is the regulatory fact most consumer pages either gloss or get wrong. No botulinum toxin product is FDA-approved for a lip flip, for lip eversion, or for gummy-smile correction. Every lip flip is an off-label use of a drug (onabotulinumtoxinA and its competitors) that is FDA-approved for other indications — glabellar lines, lateral canthal lines, forehead lines, and, for Botox Cosmetic specifically, platysma bands (for more on that labeled indication, see our article on Botox for platysma bands). Off-label use is legal and common, but it means the lip flip has not gone through the pivotal-trial process the FDA uses to confirm efficacy and safety for a specific indication. Our guide to what off-label use actually means lays out the framework; the procedure-specific version is here.
What the FDA Botox label does carry — and what applies equally to an off-label lip flip — is the boxed warning on distant spread of toxin effect. The prescribing information for onabotulinumtoxinA (BLA 103000/S-5327, 2023) warns that the botulinum toxin effect may spread from the injection site to produce symptoms consistent with botulinum toxin effects elsewhere in the body — swallowing and breathing difficulties that have, in some cases with unapproved uses, been serious or fatal. The label devotes a specific section, "Serious Adverse Reactions with Unapproved Use," to this. The realistic per-lip-flip risk of distant spread at the small doses used is very low, but the boxed warning exists for a reason and is part of informed consent. For a small-dose, superficial perioral injection, that remote risk is not the practical concern; the practical concerns are the local over-treatment effects described above.
Pregnancy, nursing, and who should skip a lip flip
Botulinum toxin is not studied in pregnant or breastfeeding patients, and current guidance is to defer elective toxin treatment during pregnancy and lactation. The conservative default — avoid it — is laid out procedure-by-procedure in our guide to aesthetic treatments during pregnancy and breastfeeding, and the lip flip is squarely in the "wait" category. Other patients who should pause or be assessed first include anyone with an active perioral infection, a known neuromuscular disorder (myasthenia gravis, ALS, Lambert-Eaton), or who is taking aminoglycoside antibiotics or other agents that interfere with neuromuscular transmission.
What to expect at the appointment and in the days after
A lip flip is a short, in-office visit. The injector examines lip posture at rest and on smile, marks two to four points along the upper vermilion border (and sometimes one or two in the lower lip), and places tiny superficial injections with an insulin-type syringe. The whole procedure is typically 10–20 minutes and uses no anesthesia beyond a topical numbing cream or ice if the patient wants it. Because the doses are small and placed superficially, bruising and swelling are usually minor.
The onset is not immediate. Botulinum toxin takes 3–7 days to begin working and roughly two weeks to reach full effect. This is a meaningful difference from filler, which is visible immediately. Practical implications:
- Do not judge the result at day two. It is too early; the muscle has not relaxed yet. If you book a follow-up, do it at about two weeks, when the effect is complete.
- Plan around events. If you want the flip for a specific occasion, treat at least two weeks ahead, and ideally do a first-time treatment even earlier so you and your injector can confirm your dose before it matters.
- Skip the straw and the heavy workout for the first day. Clinics vary, but a common-sense first 24 hours — avoid lying flat, vigorous exercise, and excessive lip manipulation — is reasonable. Follow your injector's specific aftercare instructions.
- Bruising is possible but usually minor. The vermilion border is vascular; patients who bruise easily or who take blood thinners (including over-the-counter NSAIDs and fish oil) should discuss this in advance. The broader framework for managing medication and supplement effects around toxin treatment is in our Botox and blood thinners pre-treatment guide.
Who is a good candidate — and who is not
A lip flip helps most when the lip's posture is the problem. Good candidates typically have:
- An upper lip that rolls inward at rest and looks thinner than it is.
- A long upper lip (a large distance from nose to vermilion) where a little eversion restores balance.
- A desire for subtlety — the "I just want to look a bit more refreshed, not obviously done" patient. This philosophy is exactly what our natural-looking Botox article is about.
- A mild gummy smile from LLSAN overactivity (separate injection, as above).
A lip flip is usually the wrong choice when:
- The upper lip is genuinely very thin — there is little vermilion to roll out, and filler is the honest answer.
- The goal is obvious plumpness or a big size change — toxin cannot deliver that.
- The patient is pregnant or breastfeeding (above).
- The patient has a neuromuscular condition or is on medications that interfere with neuromuscular transmission.
- The patient cannot tolerate an un-reversible result for several months. If "what if I hate it" is a dealbreaker, filler's reversibility makes it the safer psychological choice.
The decision in one paragraph
A Botox lip flip is a cheap, subtle, off-label neuromodulator technique that works by relaxing the orbicularis oris (and, for a gummy smile, the LLSAN) — not by adding volume. It lasts only about 2–3 months, cannot be reversed, shares the botulinum-toxin boxed warning, and is unforgiving of over-injection. Done conservatively by an experienced injector it is a good choice for someone who wants shape and eversion without volume; if what you actually want is plumpness, choose filler. The whole decision rests on one question — do I want shape or volume? — and on being honest about which one your lip actually needs.
FAQ
How long does a Botox lip flip last? Most sources place it at roughly 2–3 months (the Cleveland Clinic says 2–5 months). It is shorter than forehead Botox because the orbicularis oris is constantly moving when you talk, eat, and smile, which metabolizes the toxin faster. Repeat treatments every couple of months maintain the effect.
How much does a lip flip cost? Usually $80–500, most commonly a few hundred dollars, because only about 4–6 units are used. At typical per-unit pricing that is far cheaper per session than lip filler ($500–1,000+ per syringe), but because a flip lasts 2–3 months versus filler's 6–12 months, the year-one cost is closer than the per-session gap suggests.
Can a lip flip be reversed if I don't like it? No. Unlike hyaluronic-acid lip filler (which hyaluronidase can dissolve), botulinum toxin cannot be reversed; you wait for it to wear off over weeks to months. That is why conservative dosing and an experienced injector matter.
Does a lip flip fix a gummy smile? It can, but only when the cause is overactivity of the LLSAN muscle — and then the injection target is the LLSAN (about 2–4 units per side), not the orbicularis oris. If the gummy smile is skeletal or dental, toxin will not help and the right referral is orthodontic or surgical.
Is a lip flip FDA-approved? No. No botulinum toxin is FDA-approved for a lip flip or for gummy-smile correction. It is an off-label use that carries the same boxed warning about distant spread of toxin effect as approved indications.
Sources
- U.S. FDA. BOTOX® / BOTOX® Cosmetic (onabotulinumtoxinA) full prescribing information, BLA 103000/S-5327 (2023) — boxed WARNING on distant spread of toxin effect; "Serious Adverse Reactions with Unapproved Use" section; absence of a lip-flip or gummy-smile indication. https://www.accessdata.fda.gov/drugsatfda_docs/label/2023/103000s5327lbl.pdf
- Cleveland Clinic. "Lip Flip: What It Is, Botox, Results & Precautions." Typical dose ~2–4 units upper lip and ~2 units lower lip; effects last 2–5 months; 10–20 minute procedure; risks include drooling and difficulty drinking or speaking. https://my.clevelandclinic.org/health/treatments/22362-lip-flip
- Aesthetic Plastic Surgery (2026). "Clinical Outcomes and Neuromodulatory Basis of Upper Lip Eversion" — the lip flip enhances upper-lip projection primarily by neuromuscular modulation rather than volumetric augmentation. https://link.springer.com/article/10.1007/s00266-026-05727-0
- ScienceDirect / Toxicon (2024). "Dose and injection site of botulinum toxin type A for gummy smile" — 2–3 U per side can be sufficient; increasing to 5 U or higher brings more adverse effects. https://www.sciencedirect.com/science/article/abs/pii/S0041010124006305
- Fatani AH, et al. (PMC, 2023). "An Approach for Gummy Smile Treatment Using Botulinum Toxin" — Polo's 2.5-unit LLSAN/LLS injection technique and dosing review. https://pmc.ncbi.nlm.nih.gov/articles/PMC9941039
- Plastic Surgery Key / Sieber DA, Kenkel JM. "Injection of Botulinum Toxin for Treatment of the Gummy Smile" — gummy smile is hyperactivity of the LLSAN; typical starting dose ~2–4 units per side. https://plasticsurgerykey.com/injection-of-botulinum-toxin-for-treatment-of-the-gummy-smile
- Rejuvenation Resource (Dr. Janelle Vega). "Non-surgical Rejuvenation of the Lips and Perioral Area" — lip flip targets the intrinsic orbicularis oris at the vermilion border to evert the upper lip; complements HA filler. https://www.rejuvenationresource.com/articles/clinical-application-by-anatomic-region/non-surgical-rejuvenation-of-the-lips-and-perioral-area
- Aesthetic Plastic Surgery (2024). "Lip Filler Versus 'Lip Flip': Longitudinal Public Interest and a Brief Review" (PMC). https://pmc.ncbi.nlm.nih.gov/articles/PMC11815597
