What is lip filler and how does it work?
The hyaluronic acid used in lip filler is a molecule that occurs naturally in the body and attracts water. In filler products this molecule is processed into a gel so that it can stay in the tissue for longer. When the gel is injected into the lip, it creates volume where it is placed; over time it is slowly broken down by the body and its effect decreases.
One important reason hyaluronic acid is preferred for the lips is that, when necessary, it can largely be dissolved with an enzyme called hyaluronidase. Despite this property the procedure is not free of risk; however, it gives the physician a way to intervene if the result is unwanted or in some complications. For the substance itself and its use in other areas of the face, see our article “Hyaluronic Acid Filler”; for the dissolving procedure, see our article “Dissolving Filler (Hyaluronidase)”.
Filler substances that do not dissolve in the body, or that stay for a very long time, cannot be reversed if a problem arises in the lips. Be sure to ask which substance will be used on you, and ask for the product information in writing.
What is lip filler used for?
- Adding a measured amount of volume to lips that are naturally thin
- Supporting lips that have thinned and lost the definition of their border with age
- Defining the lip border and the curve at the centre of the upper lip
- Balancing mild differences between the upper and lower lip or between the right and left sides
The procedure is planned according to your own lip structure, teeth and facial proportions, not according to a photograph of someone else.
Who is it suitable for?
It may be suitable for adults who are in good general health, who have realistic expectations and who know that the result is temporary and that there may be marked swelling in the first days. The decision should be your own, and should be made without haste.
Who is it not suitable for, and what should you watch out for?
- Pregnancy and breastfeeding: safety data for this period are insufficient; the procedure is generally postponed.
- An active cold sore, infection, wound or inflamed spot on or around the lips
- A history of allergic reaction to the components of the filler or to a local anaesthetic
- A bleeding disorder or use of blood-thinning medication: do not stop your medicine on your own; talk to your physician.
- A filler previously placed in the lips whose contents are unknown or which does not dissolve
- Earlier filler still being present in the lips: repeated treatments on top of one another can lead to build-up and an unnatural appearance.
- Being under 18: lip filler for cosmetic purposes is not recommended in this age group.
- Intense and constant worry about appearance: in this situation it is more appropriate to talk and have an assessment first.
This list is not complete; tell your physician in full about your state of health, the medicines and supplements you use and any aesthetic procedures you have had before. We discuss how worry about appearance can affect the decision-making process in our article “Body Image and Aesthetic Treatments”.
Who should perform lip filler, and where?
The upper and lower lip arteries run through the lips, and the course of these vessels varies from person to person. For this reason, lip filler should be carried out in a healthcare facility by a physician who knows the anatomy of the lips well and who can deal with complications. The FDA and the American Academy of Dermatology (AAD) stress that filler is a medical procedure and should not be done in beauty salons, at home or in similar non-medical settings.
Ask in advance whether the enzyme hyaluronidase is available where the procedure is carried out and how you can reach the physician out of hours. The FDA warns that fillers sold directly to the public and treatments carried out with needle-free pressure devices have led to serious injuries; we explain this in our article “Needle-Free Filler Pens and At-Home Treatments”.
Preparing for lip filler: why does a history of cold sores matter?
Injections into and around the lips can reactivate the virus in people who have had cold sores before. Before the procedure, be sure to mention your history of cold sores, how often you get them and when your last one was. In people who get cold sores frequently, your physician may consider preventive treatment before the procedure; if there is an active cold sore on the lip, the procedure is generally postponed.
- If you know about your previous lip fillers, say when they were done and with which product.
- Ask your physician about medicines and supplements that may increase the risk of bruising; do not stop your prescription medicines yourself.
- If you have dental treatment or a vaccination planned soon, or an illness with fever, say so; your physician will assess the timing.
- Do not plan the procedure just before an important event; allow time for swelling and bruising.
- Read the consent form without rushing; ask about anything you do not understand.
If you are planning around a date such as a wedding, a graduation or a photo shoot, our article “Timing Aesthetic Treatments before a Special Event” may guide you.
The day of the procedure, step by step
- The physician assesses your lips at rest, while you speak and while you smile, and agrees the aim and the approximate amount with you. Photographs are usually taken for the record.
- The informed consent form is read; the risks and options are discussed and the form is signed.
- The lips and the surrounding area are cleaned with an antiseptic solution.
- To reduce pain, a numbing cream is applied or the area is numbed with an injection, as at the dentist. In many products the gel itself also contains a small amount of local anaesthetic.
- The gel is injected in small amounts with a fine needle or a blunt-tipped cannula. The physician decides which instrument to use; no instrument eliminates the risk of vascular occlusion.
- Throughout the treatment the physician watches the colour of the lips and your reaction. If you feel sudden, severe or unusual pain, say so immediately.
- At the end of the procedure the lips may be gently shaped and a cold compress may be applied. The colour of the lips is checked before you leave; you are given aftercare advice and details of how to reach the physician.
The AAD states that most filler treatments take 15–30 minutes. Even with numbing, the procedure is not free of pain; most people describe a prickling sensation and pressure.
With lip filler, the swelling of the first days does not show the result; you usually need to wait a few weeks to assess the final appearance. With those who want a marked change we discuss a staged approach; a measured amount matters for both a natural look and safety.
Dr. Hamza GemiciMedical Director, DoktorClub · Aesthetic Medicine Physician
The first 24 hours after lip filler
- Do not press on, massage or squeeze the lips; do not try to shape them unless your physician specifically recommends it.
- Use cold compresses only if your physician recommends them, and in the way recommended.
- Avoid very hot drinks and hard foods until the numbness wears off; you could bite or burn your lip without noticing.
- Wait for the period your physician recommends before using lipstick and lip products.
- Stay away from intense exercise, saunas, Turkish baths and very hot environments; the AAD recommends waiting until the next day before exercising.
- In the first hours, check the colour of your lips in the mirror several times. The local anaesthetic can mask pain for a while.
When does the swelling go down after lip filler?
Because of their loose tissue and rich network of blood vessels, the lips swell more than other areas of the face. In the first days the lips may look much fuller than you expected, tight and slightly asymmetrical; it is common for one side to swell more than the other. This appearance is not the result of the procedure.
| Period | Usual course | What to do |
|---|---|---|
| First 24 hours | Swelling, tenderness, numbness; small bruises at the injection points | Watch the colour of your lips; do not press on them |
| First days | Swelling is at its most noticeable; it may be greater in the mornings. There may be mild asymmetry and small firm areas that can be felt | Be patient; do not judge the result at this stage |
| First week | Swelling and tenderness gradually decrease; bruises begin to fade | If swelling or pain increases as the days go by, contact your physician |
| Second week and after | The lips soften and the gel settles into the tissue | A follow-up appointment, if your physician recommended one |
| First month | The final appearance emerges | If a touch-up or further treatment is needed, it is discussed at this stage |
According to the FDA, most side effects such as swelling and bruising appear shortly after the injection, and many resolve within a few days to a few weeks. Remember that the duration varies with the person, the amount injected and the product. You can find the table that distinguishes which swelling is usual and which is a sign of a problem in our article “Lip Filler Complications”.
Expected side effects and emergency signs
- Swelling and a feeling of tightness
- Bruising and tenderness at the injection points
- Mild asymmetry in the first days
- Small firm areas that can be felt on touching and that decrease as the swelling goes down
- Redness and mild itching
Less commonly, problems such as lumps, filler spreading beyond the lip border, a cold sore flare-up, infection, swelling that appears weeks or months later and, rarely, blockage of the lip arteries may develop. We do not go into these problems, their causes and the treatment options in detail here; they are all explained in our article “Lip Filler Complications”. We assess common beliefs about filler migration in our article “Rumour: Filler moves around the face and migrates elsewhere — What does the science say?”.
Contact the physician who treated you immediately (if you cannot reach them, go to the nearest emergency department)
- Whitening or marked paleness of the lip or of the skin of the upper lip
- A purplish-bluish discolouration spreading like a net on or around the lips
- Sudden, severe or steadily increasing pain
- Part of the lip being cold compared with the surrounding area; in the following hours, darkening colour or small blisters
Call 112 (or your local emergency number) without waiting, or go to the nearest emergency department
- Blurred vision, loss of vision, double vision or severe eye pain
- Impaired speech, facial drooping, or weakness in an arm or leg
- Shortness of breath, difficulty swallowing; rapidly increasing swelling of the lips, tongue or throat
What you should and should not do if these symptoms occur is explained step by step in our article “After Fillers: When Is It an Emergency?”. Whenever you are not sure, call your physician rather than wait.
How long does lip filler last?
The volume effect is seen immediately after the procedure; however, because of the swelling, the true result can only be assessed over the following weeks. As for how long the effect will last, there is no definite answer. The AAD states that the effect of hyaluronic acid fillers generally lasts between 4 and 12 months; this range is general information given for all areas of the face and is not specific to the lips. Because the lips are an area in constant motion, the duration is thought likely to be closer to the short end of this range. The product used, the amount and the person's metabolism also affect the duration.
There is one more point worth knowing: a decrease in the visible effect may not mean that no product is left in the tissue. In a small study that examined magnetic resonance images of 33 people who had had filler in the mid-face, hyaluronic acid was detected in the tissue for much longer than expected. This study covers the mid-face, not the lips, and may not be representative of everyone; even so, it suggests that repeat treatments should be planned according to the findings on examination, not according to the calendar.
A natural look and proportions: what is a realistic expectation?
A natural-looking lip is not about size alone; it is about the proportion of the upper and lower lip to each other, the clarity of the lip border, and how the lips fit with the teeth and the rest of the face. There is no single ideal proportion that applies to everyone; it varies with facial structure, age and personal preference. The AAD states that a measured approach to filler gives a more natural result and that marked enlargement of very thin lips may not give a good result.
- Lip filler does not change your lip structure completely; it supports the existing structure.
- A very thin lip cannot safely be turned into a markedly full lip in a single session; there is a limit to the amount the tissue can take.
- On its own, it does not correct deep lines around the lips, downturned corners of the mouth or an appearance caused by the structure of the teeth and jaw.
- Too large an amount and frequent repetition can cause the lips to project forwards and the lip border to lose its definition.
- The result cannot be guaranteed; symmetry and duration vary from person to person.
If you want a marked change, discuss a staged approach with your physician: starting with a small amount and reassessing once the swelling has gone down.
Alternatives
| Method | What it does | Point to note |
|---|---|---|
| Having no procedure | The option of waiting without taking any risk | Always a valid option |
| Botulinum toxin along the edge of the upper lip | Aims to make the upper lip look more defined by turning it slightly outwards | Does not add volume; the evidence is limited, the effect is short-lived and it can cause temporary difficulty with speaking and drinking |
| Fat injection | Provides volume with the person's own fat tissue | It is a surgical procedure; how much of the fat survives is variable, and it cannot be reversed with hyaluronidase |
| Surgical lip lift | Shortens the distance between the nose and the upper lip | It is an operation; it leaves a scar and cannot be reversed |
| Filler substances that do not dissolve | Aim to provide volume for longer | Not recommended in the lips; difficult to treat if a problem arises |
This content is for information only; it does not replace a consultation. The method that is right for you can only be determined by a physician's assessment.
Aftercare timeline
Treatment day
Do not press on or massage the lips. In the first hours, check the colour of your lips in the mirror: if there is whitening, a purplish discolouration spreading like a net or severe pain, call your physician immediately; if there are problems with vision or speech, call 112. Avoid very hot drinks until the numbness wears off.
Day 1
Swelling enters its most noticeable phase; it may be greater in the mornings. Avoid intense exercise, saunas and Turkish baths; wait for the period your physician recommends before using lipstick.
Day 3
Swelling begins to decrease; there may be mild asymmetry and small firm areas. If you have tingling followed by fluid-filled blisters (a suspected cold sore), increasing pain, increased warmth or a fever, contact your physician.
Day 7
Bruises fade and the lips begin to soften. If there is swelling that increases as the days go by, or a growing, painful lump, an assessment is needed. If you are planning dental treatment, ask your physician about the timing.
Day 14
The swelling has largely gone down. A follow-up appointment, if your physician recommended one; you can discuss the result and, if needed, a touch-up at this stage.
Day 30
The final appearance has emerged. If there is persistent asymmetry, a raised area above the lip border or a lump that can be felt, show it to your physician. Keep a record of the product name and the date of the procedure.
Questions to ask your physician
- What amount do you recommend for my lip structure; will you inject it in a single session or in stages?
- Is the product you will use hyaluronic acid? Can I have the product name and batch details in writing?
- Are the enzyme hyaluronidase and the means for emergency treatment available here?
- I have a history of cold sores; do we need to take any precaution before the procedure?
- Could the filler I had before still be in my lips; how do you assess this?
- How long should I expect the swelling to last; in what circumstances should I call you?
- What can be done if the result is fuller than I wanted?
- How can I reach you if there is a problem out of hours?
- In my case, is there another option that could be considered instead of filler or before filler?
Frequently asked questions
How long does lip filler stay?
A definite duration cannot be given. The effect of hyaluronic acid fillers is generally measured in months; the AAD gives a range of 4 to 12 months, but because the lips are a mobile area the duration may be shorter. It varies with the product, the amount and the person.
How many days does swelling take to go down after lip filler?
Swelling is usually most noticeable in the first days and then gradually decreases; how long it lasts varies with the person and the amount injected. You usually need to wait a few weeks to assess the final appearance. If swelling increases as the days go by, see your physician.
Does lip filler hurt?
A numbing cream or a numbing injection reduces the discomfort; even so, prickling and pressure are felt. Sudden, severe pain, however, is not usual and should be mentioned immediately.
Does lip filler look natural?
A treatment with a measured amount, planned according to your lip structure, can look natural. Too large an amount and treatments repeated on top of one another can lead to an unnatural appearance. If a marked change is wanted, a staged approach is more predictable.
Can someone who gets cold sores have lip filler?
Yes; however, because the injection can trigger a cold sore, you need to mention your history beforehand. Your physician may consider preventive treatment. If there is an active cold sore on the lip, the procedure is generally postponed.
If I am not happy with my lip filler, can it be reversed?
With hyaluronic acid fillers, the physician can dissolve some or all of the product with the enzyme hyaluronidase. This is also a medical procedure; there is a risk of allergy, and sometimes more than one treatment is needed. Fillers that do not dissolve cannot be reversed in this way.
If I stop having lip filler, will my lips be worse than before?
When hyaluronic acid breaks down over time, the lips are expected to return to their previous state. Data on the effect on the tissue of very large amounts and of treatments repeated over many years, however, are limited; this is another reason for a measured amount.
Sources
- Dermal Fillers (Soft Tissue Fillers) — U.S. Food and Drug Administration (FDA)
- Dermal Filler Do's and Don'ts for Wrinkles, Lips and More — U.S. Food and Drug Administration (FDA), 2023
- Fillers: FAQs — American Academy of Dermatology (AAD)
- Evaluating safety in hyaluronic acid lip injections (Safran T, Swift A, Cotofana S, Nikolis A). Expert Opin Drug Saf 20(12):1473–1486. PMID: 34328377 — Expert Opinion on Drug Safety, 2021
- Evaluation of Current Literature on Complications Secondary to Lip Augmentation Following Dermal Filler Injection (Diwan Z et al.). J Clin Aesthet Dermatol 16(7):26–33. PMID: 37560504 — Journal of Clinical and Aesthetic Dermatology, 2023
- Guideline for the Management Herpes Simplex 1 and Cosmetic Interventions (Vaghela D et al.). J Clin Aesthet Dermatol 14(6 Suppl 1):S11–S14. PMID: 34976293 — Journal of Clinical and Aesthetic Dermatology, 2021
- Hyaluronic Acid Filler Longevity in the Mid-face: A Review of 33 Magnetic Resonance Imaging Studies (Master M, Azizeddin A, Master V). Plast Reconstr Surg Glob Open 12(7):e5934. PMID: 39015357 — Plastic and Reconstructive Surgery Global Open, 2024
Medical Aesthetics Expert Board
This article has been reviewed by the DoktorClub Medical Aesthetics Expert Board.
