Fat Dissolving Injections
About Fat Dissolving Injections
Fat dissolving injections are a medical aesthetic treatment in which a substance is injected into a small pocket of fat to break down the fat cells, which the body then clears away over the following weeks. The best studied ingredient is deoxycholic acid, a laboratory made version of a substance the body uses to digest fat. It is licensed as a prescription medicine under the names Kybella in the US and Belkyra in Australia, approved for reducing fullness under the chin in adults. Other blends sold around the world, often containing phosphatidylcholine, are not licensed medicines in many countries, and regulators have warned about some of them. The treatment suits adults at a stable weight who have a small area of stubborn fat; it is not a weight loss method. Many people see visible results within two to four sessions spaced at least a month apart, with up to six allowed for the licensed chin treatment. Swelling, tenderness, bruising and numbness are very common for several days, and the chin area can look puffy for a week or more. Because treated fat cells are destroyed, results are designed to be long lasting if weight stays steady. Rules on who may inject differ by country, so a thorough medical consultation comes first.
On the day, and after
During the treatment
A treatment appointment is usually well under an hour, and the injections themselves take only part of that time. Your practitioner cleanses the skin, photographs the area so progress can be measured, and marks a grid of small injection points about a centimetre apart. Some apply a numbing cream or ice first.
A fine needle is then used to place small amounts of product into the fat layer just under the skin, one point at a time. For the chin, care is taken to stay within a safe zone, away from the nerve that controls the corner of the mouth and from glands and muscles in the neck. You will usually feel stinging or burning that builds and then fades within a few minutes, followed by warmth and tenderness. Your practitioner may apply a cold pack and give you a support garment for body areas. Before you leave, you should receive written care instructions and a clear way to contact the clinic if you are worried.
How it feels
Most people feel a stinging or burning sensation as the product goes in. It tends to build over the first few minutes and then settles, and a cold pack or numbing cream can make it more comfortable. The needle itself is fine, so the prick is brief.
Afterwards, the area feels warm, tender and tight. Many people describe it as a deep ache, similar to a bruise. Numbness is very common in the days after treatment; in the clinical trials for the licensed chin product, around two thirds of people reported it. Some people also notice tingling, itching or a firm feeling under the skin as the area heals.
Discomfort usually eases noticeably over the first few days. If pain increases rather than settles, or you notice anything unusual, contact your practitioner.
Results and maintenance
Results build gradually as your body clears the treated fat cells. Each session brings a further improvement, and the full result is usually judged at least a month after your final session. For the licensed chin treatment, sessions are spaced at least a month apart and up to six may be given; many people see visible results within two to four, though in clinical trials over half had all six.
Because the treated fat cells are destroyed, results are intended to be long lasting. The remaining fat cells can still grow, though, so significant weight gain can soften the result.
To help your results last:
- Keep your weight stable with balanced eating and regular movement.
- Attend your review appointments so your practitioner can judge whether more sessions would help.
- Look after the skin in the area with good skincare and sun protection.
Touch up treatments are not usually needed unless your weight or goals change.
Before and after your appointment
Before your appointment
Your journey starts with a consultation with a prescriber, such as a doctor, dentist, nurse prescriber or pharmacist prescriber, depending on local rules. They will examine the area, confirm the fullness is fat rather than loose skin or another cause, take your medical history and explain the risks, costs and number of sessions you are likely to need. You should have time to think before you agree to treatment.
In the week or two before your appointment:
- Ask your doctor or pharmacist whether to pause any supplements, such as fish oil or vitamin E, that can increase bruising. Never stop prescribed medication without medical advice.
- Avoid alcohol for a day or two beforehand.
- Plan your diary: the area can be very swollen for several days, so avoid booking just before an event.
- Arrive with clean skin, free of makeup on the area.
- Bring a list of all medicines and supplements you take.
Aftercare
Swelling is part of how this treatment works, so expect the area to look puffier before it looks slimmer. Gentle care helps you stay comfortable while your body clears the treated fat.
For the first few days:
- Use a cold compress wrapped in a clean cloth for short spells to ease swelling.
- Sleep with your head slightly raised after chin treatment.
- Avoid massaging the area unless your practitioner advises it.
- Skip strenuous exercise, saunas and hot baths for a day or two.
- Avoid alcohol for at least 24 hours.
- Wear any support garment you were given as instructed.
- Take pain relief only as advised by your practitioner or pharmacist.
Contact your clinic promptly if you notice a lopsided smile, difficulty swallowing, skin that turns dark, blistered or broken, a firm lump that keeps growing, or signs of infection such as heat, spreading redness or fever. A good clinic will arrange a review appointment to check your progress.
Swelling is the main thing to plan around. Under the chin it can be quite pronounced, and it commonly lasts up to around a week, sometimes longer after larger treatments. Bruising, redness, tenderness and numbness are also common, and some firmness under the skin can take a few weeks to soften.
Most people return to desk work within a day or two, though many prefer to book treatment before a quiet week. Gentle walking is fine, but save hard exercise and heat for a few days.
Less common effects include temporary weakness of the smile, which in clinical trials usually resolved within weeks, difficulty swallowing, hair loss in the area, and skin wounds or lasting lumps. Report any of these to your practitioner straight away so they can be assessed.
Safety and medical considerations
Safety essentials
Licensed deoxycholic acid is a prescription only medicine in the US, Australia and many other countries, which means a prescriber must assess you and decide it is suitable. In the UK, prescription medicines also require a prescriber, and many other fat dissolving products sold there are not licensed medicines; the government is preparing a licensing scheme for non surgical cosmetic procedures in England. In the US, the FDA warned in 2023 about unapproved fat dissolving injections linked to scarring, infections and lasting lumps, and in 2026 strengthened the Kybella label after reports of nerve problems and long lasting nodules when it was injected outside the chin area.
Good practice includes:
- A face to face consultation with a prescriber before treatment
- Genuine products from a regulated supplier, with batch numbers recorded
- An injector trained in facial and body anatomy and in managing complications
- Sterile, single use needles and a clean clinical room
- Written consent, before photos and a clear follow up plan
- Insurance that covers this specific treatment
Medical considerations
Fat dissolving injections are not suitable during pregnancy or breastfeeding, as safety has not been established. A prescriber will also check carefully if you have:
- An infection, wound or active skin condition in the treatment area
- Difficulty swallowing now or in the past, which is a reason to avoid chin treatment
- A bleeding disorder, or take blood thinners or antiplatelet medicines
- Previous surgery, filler or other treatment in the area
- A thyroid condition, swollen glands or any unexplained lump in the neck
- An autoimmune condition or allergy to any ingredient
- Loose skin, as treatment can make laxity more noticeable
Fullness under the chin is not always fat. It can come from glands, lymph nodes, the thyroid or loose skin, so a medical assessment matters. If you are taking weight loss medication or your weight is changing, your doctor can help you decide whether to wait until it has settled. This treatment is for adults only.
Patch testing
A patch test is not usually part of fat dissolving treatment. The product is injected beneath the skin, so a surface test would not reliably predict how your body responds, and licensed products do not list one as a requirement.
What matters most is a thorough medical consultation. Your prescriber will ask about allergies to any medicines or ingredients, previous reactions to injectables, and your general health. If you have a history of allergic reactions, tell them clearly so they can decide whether treatment is appropriate.
Some practitioners start with a smaller first session, particularly for body areas, to see how you respond before treating a larger area. This is a clinical decision made case by case. You should always have the name of the product being used, so you can check it and share it with your doctor if needed.
Knowing a good practitioner
Green flags
A responsible clinic treats this as the medical procedure it is. Look for:
- A thorough consultation with a prescriber who examines the area in person
- Honest advice, including telling you when treatment is not right for you
- A clear explanation of which product will be used and its licence status where you live
- Realistic expectations about the number of sessions, swelling and results
- Registration with a professional regulator, such as a medical, nursing, dental or pharmacy council
- Before and after photographs taken in the same lighting
- Written consent forms and care instructions
- A planned review appointment and a named contact for any concerns
- Evidence of training in complication management
Many good practitioners also belong to aesthetic professional bodies or voluntary registers that check training and insurance.
Red flags
Walk away if you notice any of these:
- No consultation with a prescriber, or the prescriber is never seen
- Treatment offered the same day without time to think
- Products bought online, unlabelled or with no batch number
- Claims that injections will help you lose weight or replace a healthy lifestyle
- Injecting in homes, at parties or in rooms that are not clinically clean
- Large volumes injected into big areas in one sitting
- No questions about pregnancy, swallowing, medication or medical history
- Promises of instant results with no mention of swelling or risks
- No written aftercare and no way to contact the clinic afterwards
After treatment, seek medical help urgently if you have difficulty swallowing or breathing, changes to your vision, a lopsided smile, skin that turns dusky, grey or black, or a rapidly spreading, hot, painful area.
Questions to ask
These questions help you choose a safe, skilled practitioner:
- Which product will you use, and is it a licensed medicine here?
- Who will prescribe it, and will I meet them in person?
- What is your medical or healthcare registration?
- How many sessions will I need, and how far apart?
- What side effects should I expect, and how long does swelling last?
- What would you do if I had a complication?
- When will you see me again to review my results?
Frequently asked questions
Do fat dissolving injections really work?
Deoxycholic acid, licensed as Kybella in the US and Belkyra in Australia, has clinical trial evidence for reducing fat under the chin. Evidence for many other blends is limited, and some have prompted regulator warnings. Results depend on choosing the right product, the right area and a skilled, medically supervised practitioner.
How many sessions of fat dissolving do I need?
Many people see visible results within two to four sessions, spaced at least a month apart. For the licensed chin treatment, up to six sessions can be given. Your prescriber will assess your progress at each review and advise whether further sessions would make a worthwhile difference.
How long does swelling last after fat dissolving injections?
Swelling commonly lasts up to around a week, and sometimes longer after larger treatments. Under the chin it can be quite noticeable at first. Cold compresses, sleeping slightly propped up and avoiding heat and alcohol can help. Contact your clinic if swelling affects swallowing or breathing.
Who can do fat dissolving injections?
It depends on where you live. Licensed deoxycholic acid is prescription only in many countries, so a prescriber must assess you first. Some places allow trained practitioners to inject under medical oversight, while others restrict it to healthcare professionals. Always check the injector's registration and who prescribes the product.
Are fat dissolving injections permanent?
The fat cells that are destroyed do not come back, so results are designed to be long lasting. However, the fat cells that remain can still grow, so significant weight gain can reduce the result. Keeping your weight steady is the best way to maintain your new contour.
What are the side effects of fat dissolving injections?
Swelling, bruising, pain, numbness, redness and firmness in the area are very common and usually temporary. Less common risks include temporary weakness of the smile, difficulty swallowing, skin wounds, infection and lumps that may not settle. Choosing a qualified prescriber and licensed product helps keep these risks low.
This guide is general information, not medical advice. Speak to a qualified practitioner, and to your GP if you have a medical condition, before booking.