Guide · Lip flip vs lip filler
Lip flip vs lip filler rolling the lip out, or adding volume
A lip flip and lip filler are often confused, but they work in completely different ways. One relaxes a muscle so the upper lip turns out slightly; the other adds gel to build volume and shape. Here is who suits which, how long each lasts and what can go wrong.
Quick answer
- A lip flip is a tiny wrinkle-relaxing injection into the muscle along the upper lip border, which lets the lip roll outwards slightly so more of the pink shows; it adds no volume. Lip filler is hyaluronic acid gel injected to add real volume and shape, and to define the border.
- A lip flip suits people who want a subtle change, whose upper lip seems to disappear when they smile, or who have fine lines above the lip; filler suits thin or uneven lips and fullness lost with age. A lip flip takes effect within about a week and is short-lived, while lip filler fullness commonly lasts about six to twelve months.
- Lip flip side effects are usually mild but particular: difficulty drinking through a straw, whistling, spitting or saying some sounds, and slight asymmetry, which fade as the effect wears off. Filler brings swelling and bruising, and the rare but serious risk of filler blocking a blood vessel.
- Both are medical injections done by a doctor. At IN Eternity Clinic, Pacific Plaza, Dr Sin Yong performs wrinkle-relaxing injections and lip filler and advises which suits your lips, priced at consultation. SkinRev Lab does not inject; it offers lip blush for colour instead.
The difference
Lip flip vs lip filler: what each one does
The lips are surrounded by a ring of muscle, the orbicularis oris, which purses and tightens the mouth. In a lip flip, a doctor places a very small dose of a wrinkle-relaxing injection into the edge of this muscle along the upper lip border. As the edge relaxes, the upper lip rolls outwards a little, so more of the pink part shows, particularly when you smile. Nothing is added to the lip.
Lip filler works the other way round. A hyaluronic acid (HA) gel is injected into the lip to add volume, define the border, balance an uneven lip or restore fullness lost with age. The change is physical and visible straight away, and HA filler can be dissolved with an enzyme if needed.
So the first question is what you want to change: how much of your upper lip shows, or how full and shaped your lips are. A lip flip cannot create volume that is not there, and filler does not relax a lip that rolls inwards when you smile.
Side by side
Lip flip vs lip filler at a glance
| Lip flip | Lip filler | |
|---|---|---|
| What it is | A small wrinkle-relaxing injection into the lip-border muscle | Hyaluronic acid (HA) gel injected into the lip |
| What changes | Upper lip turns out slightly; more pink shows | Volume, projection, border definition and symmetry |
| Adds volume | No | Yes |
| When you see it | Within about a week | Straight away, clearer once swelling settles |
| How long it lasts | Temporary; up to about three to four months in reports | Commonly about six to twelve months |
| Common effects | Trouble with straws, whistling and some sounds; mild asymmetry | Swelling, tenderness, bruising |
| Rare but serious | Weakness around the mouth, difficulty holding liquid | Filler blocking a blood vessel (vascular occlusion) |
| Can it be reversed | No; it wears off on its own | HA can be dissolved with hyaluronidase |
| Who performs it | A doctor | A doctor |
| At IN Eternity Clinic | Priced at consultation | Priced at consultation |
The evidence
How a lip flip works, and what the research shows
A lip flip uses a very small total dose, usually split across about four points along the upper lip border and kept to the central part of the lip. Staying central limits spread to the neighbouring muscles that lift the corners of the mouth, which could otherwise affect the smile.
The evidence is thin. A 2025 systematic review of the lip flip found only seven studies that described injection sites and doses, several of them case reports or small case series. They reported consistent outward turning of the upper lip and improved contour, with effects often visible in the first week and high satisfaction, but the authors called for larger controlled trials. An earlier report of 18 patients treated for vertical lines above the lip noted smoother lines plus upper lip fullness and eversion as a side benefit.
Wrinkle-relaxing injections are prescription medicines in Singapore, and doses for the lip are much smaller than for the forehead or frown lines. The skill lies in the placement and the amount, which is why a lip flip should only be done by a doctor.
Who suits which
Lip flip, filler, both or neither?
Wait on both if you are pregnant or breastfeeding, or have an active cold sore or infection on the lips. A lip flip is not suitable with neuromuscular conditions such as myasthenia gravis, and anyone who relies on fine lip control, such as a wind instrument player or singer, should discuss timing carefully. A good consultation may end with a smaller change than you expected, or with advice to do nothing.
- Upper lip that thins or seems to vanish when you smile, with reasonable volume at rest: a lip flip may suit.
- A subtle change with no added volume, or a first, temporary step: a lip flip.
- Fine vertical lines above the upper lip from pursing: a lip flip may soften them; etched lines may need other treatment too.
- Thin lips, uneven sizes, a flat border or fullness lost with age: filler, which adds actual volume.
- Both concerns together: some people have filler for shape and a lip flip for show; the doctor decides the order.
- Pale or patchy lip colour: neither; lip blush adds colour.
- Old filler that feels lumpy or has moved above the lip line: an assessment, and possibly dissolving, before anything new.
How long each lasts
How long a lip flip and lip filler last
A lip flip is temporary. The muscle gradually regains its strength as nerve endings recover, and the lip returns to how it was. In the published reports the effect lasted up to about three to four months in some people, and because the dose is so small it can wear off sooner. It is repeated only if you want to keep the effect.
Lip filler lasts longer. In a meta-analysis of HA lip augmentation, 91% of people still had fuller lips at two months, 74% at six months and 46% at twelve months. Lips move constantly, so filler here tends to fade sooner than in the cheeks or chin.
Visible fullness and actual filler are not the same thing: HA can remain in the tissue after the visible effect fades, so frequent top-ups can build up and spread above the lip line. A review before each top-up is sensible.
Lip flip risks
Lip flip side effects: straws, speech and asymmetry
Because a lip flip relaxes part of the muscle that seals the lips, the typical side effects are functional. The 2025 review reported difficulty drinking through a straw, whistling, spitting and pronouncing sounds that need closed lips, such as p and b. Most settled within two to four weeks, though some lasted a month or longer. Mild bleeding, bruising, swelling, tenderness and slight asymmetry were also reported.
Rarely, more of the muscle is affected than intended. One case report described temporary weakness around the mouth that made it hard to hold water in. There is no antidote, so these effects simply have to wear off, which is why conservative dosing and precise placement matter more than how much lip show is achieved.
Tell the doctor about any neuromuscular condition, recent infection around the mouth, previous reactions, and medicines that can interact, such as certain antibiotics.
Lip filler risks
Lip filler risks: from bruising to a blocked vessel
Most lip filler side effects are mild and settle on their own. In a meta-analysis pooling 1,496 people, tenderness, swelling and bruising were the most frequent, while lumps from a foreign-body reaction, cold sore flares and allergic swelling were each uncommon. A bluish tint can appear if HA sits too close to the surface.
The serious risk is vascular occlusion, where filler blocks or presses on an artery and cuts off blood supply to the lip skin. Each lip has its own artery, and in a study of 193 specimens it ran mostly beneath the muscle on the inner side (78.1%), sometimes within the muscle (17.5%) and occasionally just under the skin (2.1%), most variably in the midline. Expert consensus is that most complications can be avoided with proper planning and technique, and that the clinician must be ready to treat them.
- Skin on or around the lip turning pale, white, blotchy or dusky after filler is an emergency.
- Pain that keeps increasing rather than settling needs urgent attention.
- Any change in vision after filler anywhere on the face is an emergency.
- Contact the clinic that treated you at once, or go to an emergency department.
Colour, not volume
Lip blush: a non-injectable option for colour
Many people who ask about a lip flip or filler are really unhappy with lip colour or a faded border rather than shape. Lip blush is semi-permanent cosmetic tattooing that adds soft colour through the whole lip, evens out tone and clarifies the border. It changes colour, not volume or lip show, and typically lasts one to three years.
Lip blush can be combined with injections, but not on the same day. A dermatology review of permanent make-up notes that cosmetic tattoo can shift or look different when filler is later injected beneath it, so it usually makes sense to settle any filler first and design colour around the final shape. If you get cold sores, say so beforehand, because lip work can trigger them.
At SkinRev Lab, Signature Lip Blush is priced at consultation, with shade selection and design included. It is a beauty service done by a trained artist, not a medical treatment.
Where to go
Lip injections and lip blush in our network
Lip injections are medical treatments. At IN Eternity Clinic, 9 Scotts Road, #12-01 Pacific Plaza, beside Orchard MRT, Dr Sin Yong performs wrinkle-relaxing injections and lip filler, and examines your lips at rest and in motion before advising whether a lip flip, filler, both or neither suits you. Where earlier filler is involved, he maps it with ultrasound before any dissolving. Treatment is priced at consultation by the clinic; WhatsApp +65 8815 3008.
SkinRev Lab, at #B1-28 CityLink Mall by City Hall MRT, is a non-invasive centre and does not inject. It offers Signature Lip Blush for colour (priced at consultation) and the HydraFacial Perk Lip add-on for dry, lined lips (ask at the counter), and can pass injection enquiries to IN Eternity Clinic. Results vary between people.
Sources
References & sources
- Pitchford CA, Desrosiers AS, Tolkachjov SN. The lip flip: a systematic review of botulinum toxin lip augmentation. Arch Dermatol Res. 2025;317(1):765.
- Semchyshyn N, Sengelmann RD. Botulinum toxin A treatment of perioral rhytides. Dermatol Surg. 2003;29(5):490-495.
- Czumbel LM, Farkasdi S, Gede N, et al. Hyaluronic acid is an effective dermal filler for lip augmentation: a meta-analysis. Front Surg. 2021;8:681028.
- Cotofana S, Pretterklieber B, Lucius R, et al. Distribution pattern of the superior and inferior labial arteries: impact for safe upper and lower lip augmentation procedures. Plast Reconstr Surg. 2017;139(5):1075-1082.
- Signorini M, Liew S, Sundaram H, et al. Global Aesthetics Consensus: avoidance and management of complications from hyaluronic acid fillers. Evidence- and opinion-based review and consensus recommendations. Plast Reconstr Surg. 2016;137(6):961e-971e.
- Ghafari G, Newcomer J, Rigali S, Liszewski W. Permanent makeup: a review of its technique, regulation, and complications. J Am Acad Dermatol. 2024;91(4):690-698.
Common questions
Your questions,
answered
What is a lip flip?
A lip flip is a small wrinkle-relaxing injection into the muscle along the upper lip border. As the muscle edge relaxes, the upper lip rolls outwards slightly so more of the pink shows, especially when smiling. It does not add volume.
How long does a lip flip last?
It is temporary. The effect usually appears within about a week and, in published reports, lasted up to about three to four months in some people; because the dose is small, it can wear off sooner. Lip filler usually lasts longer, commonly six to twelve months.
Lip flip or lip filler for thin lips?
If your lips are thin at rest, filler is usually the more effective option, because a lip flip cannot add volume. A lip flip suits lips with reasonable volume that seem to disappear when you smile. Some people combine the two after a doctor's assessment.
Does a lip flip make your lips bigger?
Not in volume. It makes the upper lip look slightly fuller by turning more of the pink part outwards. For physically bigger lips, filler is the option to discuss with a doctor.
Can I drink from a straw after a lip flip?
It may be harder for a few weeks, because the muscle that seals the lips is partly relaxed. Difficulty with straws, whistling and spitting are the most commonly reported side effects, and they usually settle as you adjust or as the effect wears off.
Does a lip flip affect speech?
Some people notice that sounds needing closed lips, such as p and b, feel slightly different for a while. In the reports reviewed this was usually mild and temporary. If your work depends on precise speech or a wind instrument, discuss timing with the doctor.
Can a lip flip go wrong?
The usual problems are mild asymmetry and temporary trouble with straws or some sounds. Rarely, too much of the muscle is affected and holding liquid becomes difficult until it wears off. Conservative dosing and precise placement by a doctor keep these risks low.
Can I get a lip flip and lip filler together?
Some people do, using filler for volume or shape and a lip flip for more lip show. Whether to combine them, and in what order, is a doctor's decision after seeing how your lips look at rest and move when you talk and smile.
How much is a lip flip in Singapore?
It depends on the assessment and whether filler or other treatment is also planned. At IN Eternity Clinic, lip injections are priced at consultation by the clinic after Dr Sin Yong has examined your lips. SkinRev Lab does not inject.