Lip Flip

What is a lip flip?

A lip flip is an injection of a small amount of botulinum toxin into the ring-shaped muscle around the mouth (orbicularis oris), along the upper lip border (vermilion border). The aim is to partly relax the section of the muscle at the edge of the lip so that the upper lip turns slightly outwards. Nothing is added to the lip; the visible change comes from the position of the lip, not from volume.

According to a systematic review that brings together studies on the subject (a publication that assesses the combined results of studies selected using set criteria), a lip flip is a technique aimed at changing the contours of the lips and how full they look, without adding volume. These studies reported a consistent outward turn and change of outline in the upper lip, and side effects were found to be mild and temporary. However, of the 48 publications screened, only seven could be included in the review, because they described the injection points and amounts in detail.

A lip flip is one of the off-label uses of botulinum toxin: it is outside the uses covered by the product's licence or approval. Although interest in this use is growing, publications on the subject are very limited. A review of lip rejuvenation options also distinguishes between the two methods: botulinum toxin gives the lip a subtle outward turn, while volume and definition are achieved with hyaluronic acid (HA) fillers.

You can read about how botulinum toxin works in general, its known risks and its other uses on the Botulinum Toxin page; a lip flip is a small application of this substance aimed only at the upper lip. The dose, dilution and injection points are decided individually for each person; these decisions are made by the doctor who carries out the treatment.

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Where does the name come from?

‘Lip flip’ is an English expression: ‘lip’ is the lip, and ‘flip’ means to turn over or turn inside out. The name describes the red part of the upper lip turning slightly further outwards and becoming visible. There is no established Turkish equivalent; in Turkish medical language it is described as turning the upper lip outwards with botulinum toxin.

In everyday Turkish, this treatment is also called ‘dudak botoksu’. The Turkish word ‘botoks’ comes from a product name. The active ingredient is botulinum toxin type A, and there are several commercial products containing this active ingredient, each with a different formulation. This is why the term botulinum toxin, the name of the active ingredient, is preferred to a product name.

The name has become more popular, but the scientific evidence has not grown stronger at the same pace. A study of ten years of search data found that searches for lip filler and for lip flip rose together; searches for filler stayed higher throughout, while searches for lip flip increased over time. According to the study, the substance most often used for lip filler is hyaluronic acid, because it is compatible with the body's tissues and reversible.

Search trends show only how much a treatment is talked about, not who it is suitable for. Although interest is growing, there are very few publications on this use. In short, the name ‘lip flip’ only tells you which treatment is meant; how widely the name is used is not a measure of what you can expect from the treatment.

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Why does the lip turn outwards when the muscle relaxes?

The orbicularis oris is the muscle that surrounds the mouth. A lip flip targets its thin section near the edge of the lip (pars marginalis). The aim is to partly relax this section of the muscle to achieve a subtle outward turn of the upper lip. A short case report (a publication reporting the experience of a small number of patients) describes injections given superficially along the lip border, avoiding the corners of the mouth and the deeper muscle layers.

At its core, this relies on the known effect of botulinum toxin: a small amount of toxin causes local relaxation in the muscle it is injected into. In cosmetic treatments, the effect is reported to usually take two weeks to appear fully. The authors of a study that measured the upper lip also explain the change they saw by selective relaxation of the muscle, not by an increase in volume.

This muscle is not built the same way in everyone. In a study that examined the upper lip with ultrasound, the section of the muscle at the edge of the lip was seen only at trace level in 20.0% of volunteers; it was found to be well developed and continuous in 42.9%, and present but discontinuous in 37.1%. According to the researchers, the structure of this section varies markedly from person to person, and this difference needs to be taken into account when botulinum toxin is injected into the upper lip.

Changes that come with age also matter. A study that used ultrasound to measure the angle of the muscle in 30 volunteers reported that this angle decreased significantly with age. The decrease was most marked in the upper lip and in women, and it was also linked to a more inward-turned lip shape. Two lips that look the same from the outside may not respond to the treatment in the same way if their muscle structure is different.

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An upper lip that looks thin

Most lip flip studies look at an upper lip that appears thin at rest. What these studies measure is not the volume of the lip, but how much of the red part is visible and the height of the skin between the nose and the lip. The few measurement studies that have been carried out look at these distances.

In a prospective study that followed 17 women, measurements from three-dimensional facial photographs showed a small but significant increase in upper lip height 15 days after treatment, while lip volume did not change. The participants' own ratings of the area around their lips also improved significantly. However, this is a small study, and its published abstract does not mention a comparison group; its level of evidence is given as level IV, one of the lower steps in the hierarchy of evidence.

In a case series (a study that reports the results of a group of patients without making a comparison) in which three patients were followed with three-dimensional imaging, the height of the red part of the upper lip increased after two weeks, and the height of the skin between the nose and the lip decreased. There was a trend towards a larger lip surface area, but this difference was not statistically significant. The authors state that the treatment can be an option only if used with caution.

What these findings mean for you: the measured change is subtle and does not make the lip bigger. An ultrasound study reported that age-related changes in the lip muscle are linked to a more inward-turned lip shape. Even so, whether the thin appearance of your lip comes from volume loss or from the position of the muscle is determined at a consultation.

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An upper lip that curls inwards when you smile

In some people, the upper lip curls inwards rather than lifting when they smile, and less of its red part shows. When too much gum shows on smiling, this is usually attributed to the lip rising too high, a short upper lip, or the structure of the teeth and jaws. Inward curling, by contrast, is discussed as a pattern of movement separate from these causes.

In an exploratory case series looking at this type of smile, 94 people had a small amount of botulinum toxin injected, from inside the mouth, into the section of the muscle at the edge of the lip. At the follow-up on day 15, a change towards a lesser degree of inward curling was seen. Functional changes were reported as mild, temporary and resolving on their own; the ability to close the mouth was generally preserved.

You should also know the limits of this study: the rating scales used are preliminary tools, the study is a case series, and it has no comparison group. The authors say that new studies with objective muscle measurements, three-dimensional imaging and comparative designs are needed. Because there can be more than one reason why the gums show when you smile, which one is most relevant in your case is determined at a consultation.

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The difference between a lip flip and lip filler

The key difference: a lip flip does not add volume to the lip; lip filler does. So the two are not different routes to the same goal, but different answers to different questions. According to a review of lip rejuvenation options, botulinum toxin creates a subtle outward turn of the lip, while hyaluronic acid fillers provide volume and definition. A surgical lip lift also turns the red part of the lip outwards, by shortening the skin between the nose and the lip.

Measurements support this distinction too. In the study that followed 17 women, upper lip height increased after a lip flip, but lip volume did not change. So if the main issue with a thin-looking lip is volume loss, a lip flip does not address it. Options for volume are described separately on the Lip Filler page.

Which method is considered first in the lower face also matters. According to a treatment guide for the lower face, this is an advanced treatment area, and fillers play a more important role here than muscle relaxants. For lines caused by movement (dynamic lines), fillers are recommended for structure and support before muscle relaxants are considered. According to an international consensus statement, however, botulinum toxin is considered the first option when the main cause of facial imbalance is excessive muscle contraction.

The authors of the study on search data suggest that a lip flip may be an option for people who have reservations about filler. These reservations are understandable; but before choosing one method instead of the other, it needs to be established whether the change in your lip comes from volume or from the position of the muscle.

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How strong is the evidence?

The short answer: limited. Publications on lip flips consist of small case series, small observational studies and one systematic review summarising them. A literature search found no randomised controlled trials (trials in which participants are randomly assigned to groups) comparing a lip flip with a placebo or with another method.

In the systematic review, only seven of the 48 publications screened could be included in the assessment, because they clearly described the injection points and amounts. These studies report that patients were highly satisfied and that side effects were mild and temporary. However, the number of studies in the review is small, and satisfaction is based on the patients' own ratings.

The individual studies are also small. The prospective study using measurements included 17 women, and its level of evidence is given as level IV. The authors of a three-patient case series present the treatment as an option that can only be recommended with caution. The authors of a recent case report covering three patients state clearly that their findings should be interpreted as preliminary findings: the sample is very small, there is no control group, there was no blinded assessment and the follow-up period is short.

The question of how long the effect lasts is also still unanswered. The abstracts of the publications reviewed report early results and give no long-term follow-up data. For this reason, it is not possible to state how long the effect of a lip flip lasts. Data on how long botulinum toxin lasts in general come from other areas and cannot be applied directly to the lip.

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Limits of this treatment

A lip flip slightly changes the position of the upper lip; it does not answer most other concerns. In a study based on measurements, upper lip height increased, but lip volume did not change. So a lack of volume, whether it comes with age or from a person's natural build, is not corrected by this treatment. For a lack of volume, hyaluronic acid fillers are considered as an option; where the skin between the nose and the lip is long, a surgical lip lift is considered.

The effect depends on the muscle relaxing and is not permanent. In the cosmetic use of botulinum toxin, the effect is reported to usually take two weeks to develop fully and to fade over time; for a lip flip, there is no reliable data on how long it lasts. Results are also reported to be more noticeable for lines that appear with movement than for lines visible at rest.

A treatment guide for the lower face regards this area as an advanced treatment area; it stresses avoiding overcorrection of the lips and keeping the proportions between the lips and the chin. A lip flip does not turn the lip into a target separate from the rest of the face; the lips, the chin and the face as a whole are assessed together.

This information is not meant to put you off, but to help you compare the options. Which path makes sense for you (a lip flip, lip filler, another method or none of these) is decided by the assessment at your consultation and by your own decision. Deciding not to have any treatment is also a valid outcome.

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The muscle around the mouth and safety

Botulinum toxin treatment in the lower face needs a different kind of care from treatment in the upper face. According to an expert consensus on the muscles of the lower face, the muscles in this area have important functions; this makes treatment particularly difficult and increases the risk of side effects and complications. In addition, the anatomy of these muscles varies from person to person.

In a lip flip, the target is the thin section of the orbicularis oris muscle near the edge of the lip. An ultrasound study showed that this section develops markedly differently from person to person. A case report describes injections given superficially, avoiding the corners of the mouth and the deeper muscle layers. In short, the treatment area is small and its anatomical boundaries are narrow.

The same muscle is also the source of the vertical lines above the lip. In a randomised trial comparing two different total amounts for lines around the mouth that become more noticeable with movement, the severity of the lines decreased significantly in 60 women. Most adverse effects were mild to moderate and of the kind typical of lip treatments; they occurred more often as the amount injected increased. A lip flip and treatment for upper lip lines target the same muscle, but their aims are different.

An international consensus statement recommends deciding the dose and injection site by assessing the target muscle together with the neighbouring muscles and surrounding tissues; the aim is not to paralyse the muscle but to regulate how it works. The dose, the number of injection points and the depth are decisions made individually for you by the doctor who carries out the treatment.

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Known risks

The side effects reported for a lip flip are mostly mild and temporary, but because they affect how the lip works, they are noticeable in everyday life. The main side effects reported in the systematic review are difficulty whistling and difficulty drinking through a straw; these are reported to resolve within weeks.

In the prospective study that followed 17 women, all adverse effects were mild and temporary: temporary numbness and limited function were reported, and these resolved on their own within 30 days. In a three-patient case series, mild weakness of the muscles around the mouth and inability to close the lips fully lasted about one month in all three patients.

The effect on speech has been little studied. In a recent case report covering three patients, no speech problems, difficulty moving the mouth, asymmetry or impaired mouth closure were reported during a short follow-up period; the authors stress that this is a preliminary finding. A risk can still exist even if no problem has been reported.

Asymmetry is also a known risk. A systematic review of aesthetic botulinum toxin treatments covering 8,787 people reported lip asymmetry and imbalance at a rate of 6.9% after lower face treatments; all of these were reported to resolve on their own. Another review of complications after facial treatments also describes functional problems around the mouth and facial asymmetry as generally mild and resolving on their own.

General risks also apply: mild bruising and swelling can occur. Neuromuscular disorders, a tendency to form keloids (excessive, raised scars) and allergy to any of the product's ingredients are listed among the contraindications (reasons not to have the treatment); elective cosmetic procedures are reported to be postponed during pregnancy. Before the procedure, you will be asked about blood thinners, antiplatelet medicines (medicines that stop blood platelets from clumping together) and supplements that can affect bleeding. Do not stop any prescribed medicine on your own. If needed, the procedure is planned or postponed after consulting the relevant doctor. The rates in this section come from other studies; they are not this clinic's data.

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