top of page

Fat dissolving injection guide: what matters before treatment

Ariana Wen

August 13, 2026

Fat dissolving injection guide: what matters before treatment

Key takeaways


  • BELKYRA is indicated for adult fullness associated with submental fat.

  • Deoxycholic acid physically disrupts cell membranes. Pain and swelling are common reactions.

  • Required volume and vial count are major per-session cost drivers.

A fat dissolving injection can mean a different drug, body area, and goal, so one broad name can hide key differences. This matters when you compare options in Toronto. BELKYRA contains deoxycholic acid and is indicated for adults with moderate-to-severe fullness linked to fat under the chin. Other drugs and body areas need to be judged on their own terms. Start with the drug, the proposed area, and the cause of the fullness. These points shape what its result, risk, and cost can mean for you. If your concern is under your chin, our North York double-chin treatment page describes the BELKYRA service we offer.


It is easy to see why the broad name is appealing. It sounds as if one treatment can be moved from one spot to another. The actual choice is more specific. A named drug has a named use, and the cause of the fullness can change whether your anatomy fits that use.


That can feel like a lot to sort out at first. The narrower terms make the choice easier to understand.


What a fat dissolving injection does


BELKYRA contains deoxycholic acid. When injected into tissue, the drug physically breaks cell membranes. This is how BELKYRA acts where it is placed.


The drug name gives you a firm place to start because BELKYRA has its own use, results, risks, and course of care. The body area is just as important, and its stated use concerns fullness linked to fat under the chin in adults. The drug is placed into tissue and acts on cell membranes there.


Under-chin fullness can occur at any body mass


Submental fat can occur regardless of body mass, so you can have under-chin fat at any body size. Total body mass is one measure, while the cause of one full area is another.


Ideal candidates have unwanted under-chin fullness mainly caused by pre-platysmal fat. In this profile, submental fat causes the fullness, while excess loose skin is a different cause. So are drooping glands under the jaw and bands in the platysma muscle.


So the key anatomy question is simple: what causes the fullness under your chin? Fat is one answer, while the candidate profile also names loose skin, gland position, and muscle bands. Your total body mass cannot answer that local question on its own.


Under-chin fat is found across body masses. It is a feature of one area, and the ideal candidate test focuses on what makes that area full. Your shape does not have to match an assumed body type for this concern to exist.


Match the ingredient, area and evidence


The same broad label can sit over very different products and uses. Match the drug to the area and concern before you weigh the result.


Ingredient or product

Treatment area

Relevant concern

Evidence boundary

BELKYRA, a deoxycholic-acid injection

Under the chin

Moderate-to-severe fullness associated with submental fat in adults

Deoxycholic acid

Under the chin

Fullness caused mainly by fat in front of the platysma muscle

The ideal candidate profile points to submental fat, not excess skin laxity, gland position, or neck bands.

ATX-101, following its approval for SMF reduction

Jowl area and fat around or behind the armpit

Localized fat in those reported areas

A review describes successful off-label use in these areas.

Deoxycholic acid at 10 mg/mL

Flanks

Mild-to-moderate flank fat

A study of 30 adults used two sessions six weeks apart. At Week 12, 86.7% had improvement on an aesthetic scale, with reductions in waist circumference and fat thickness measured by caliper and ultrasound.

Phosphatidylcholine, sodium deoxycholate, or both in unapproved injections

Not established by the ingredient name alone

Claims attached to an unapproved mixture

The United States Food and Drug Administration has not evaluated the safety or effectiveness of those unapproved ingredients.


For fat dissolving injections in Toronto, a local address does not make all five rows alike. BELKYRA has a stated adult under-chin use, while the ATX-101 row covers reported off-label use in two other areas. The flank result came from 30 adults, and the last row covers unapproved drug mixes. Match your concern to the row that names the same drug and body area.


Will a fat dissolving injection work under the chin?


BELKYRA results show measured change under the chin, but response size varied across the treated group. On a combined rating scale for under-chin fat, 68.2% of treated subjects had at least a one-grade response. The rate was 20.5% for people who received a placebo.


BELKYRA response rates exceeded placebo for one-grade, two-grade, and MRI-defined changes, with two-grade responses least common.

At least a two-grade response occurred in 16.0% of BELKYRA-treated people and 1.5% of the placebo group. The larger change was less common than the one-grade result in each group. Your idea of a useful change may differ from a study cut-off, so the size of the response matters too.


Magnetic resonance imaging gave a third view of change. Using a prospectively defined MRI threshold of at least a 10% reduction in submental volume 12 weeks after the last treatment, 43.3% of BELKYRA-treated subjects and 5.3% of placebo-treated subjects were responders.


The three measures give a better answer than a broad yes. The 68.2% rate is for at least a one-grade response, while the 16.0% rate is for at least a two-grade response. The scan rate uses its own volume cut-off and time point. "Worked" covered more than one type of change, and it did not mean the same degree of change for each person.


What drives fat dissolving injection cost?


Cost depends a great deal on how much deoxycholic acid is required. The amount and spread of under-chin fat affect that volume, while vial count is a main cost driver for each session. Two people considering BELKYRA can need a different volume and number of vials.


Best results are achieved with at least two sessions, according to the candidate and treatment guidance. The required volume, vial count, and treatment course all belong in the cost picture.


A single session price tells you only part of the likely spend because it may leave out the vial count and full course. What volume is required, and how many vials are used per session? How many sessions are planned? The first two points drive the session cost, while the third sets out the course being considered. This keeps the price tied to the amount of drug and the length of care it describes.


Swelling and other local reactions are common


Swelling occurred in more than 10% of BELKYRA-treated patients. So did pain, bruising, changed feeling, redness, firm spots, small lumps, and itching at the shot site. A sore or swollen area can be a real part of care, even when the goal is less fullness under the chin.


Nerve injury and trouble swallowing were also seen in BELKYRA-treated patients, and these two problems lasted for several months in some cases. Pain, swelling, bruising, and changed feeling belong to the group seen in more than 10%. Nerve injury and trouble swallowing are the reactions tied to the longer time above.


Some conditions rule BELKYRA out or require a pre-treatment discussion


Two conditions are direct reasons not to use BELKYRA. Do not use it if you are allergic to deoxycholic acid or another ingredient in the drug. It also should not be used when there is an infection at the shot site on the chin or neck.


Other situations require a discussion with a healthcare professional before treatment. The Canadian patient information names these points:

  • Previous or planned surgery involving the face, neck, or chin, as well as previous or planned cosmetic treatment in those areas.

  • Difficulty swallowing.

  • Pregnancy or plans to become pregnant, because it is not known whether BELKYRA can harm an unborn baby.

  • Being younger than 18 or older than 65.

An allergy or infection is a do-not-use condition, while the other four points call for a talk with a health professional before care. Past surgery or cosmetic work can involve the face, neck, or chin. Trouble swallowing has its own warning, and pregnancy plans matter because the effect on an unborn baby is not known. The age instruction applies to people under 18 and over 65.


This gives you two clear checks. An allergy to the ingredients or an infection at the planned site rules BELKYRA out. Prior or planned work on the area, trouble swallowing, pregnancy plans, and age outside 18 to 65 require a talk before treatment.


Before BELKYRA treatment, patients should tell their health professional about past or planned surgery and cosmetic work involving the face, neck, or chin. Difficulty swallowing should also be discussed with a health professional before treatment. These are useful points to gather before the visit.


Pregnancy has a clear reason for that talk because it is not known whether BELKYRA can harm an unborn baby. The age point has exact bounds too. People younger than 18 and older than 65 should discuss their age with a health professional before care.


Unapproved products and unsafe injection can cause serious harm


Some unapproved fat-dissolving shots in the United States contain phosphatidylcholine, sodium deoxycholate, or both. The Food and Drug Administration has not assessed their safety or effect. A familiar drug name does not change their status.


The agency has received reports of permanent scars, serious infections, skin deformities, cysts, and deep painful knots after unapproved shots. Unsafe injection by an unlicensed person can raise the risk of scars, skin infections, and severe harm. Do not buy ingredients for unapproved fat-dissolving shots or inject those drugs yourself.


Placement matters even for a named drug. United States details for KYBELLA say it should not be injected into, or within 1 to 1.5 centimetres of, salivary glands, lymph nodes, or muscles. A shot into an artery or vein can harm the blood vessel.


The product and the way it is given both affect the risk. Reports about an unapproved mix include scars, infections, skin changes, cysts, and painful knots. KYBELLA has firm placement limits near glands, nodes, and muscles because a shot into an artery or vein can harm that blood vessel.


The United States warning gives one firm action: do not buy ingredients for unapproved fat-dissolving injections or inject the drugs yourself. For KYBELLA, safe placement must also account for the nearby glands, lymph nodes, muscles, arteries, and veins named in its prescribing details.


Does fat come back after fat dissolving injections?


Targeted fat cells destroyed by BELKYRA do not regrow, but remaining fat cells can still grow larger with weight gain. Fullness may also return in nearby areas. The treated contour can therefore change while the destroyed cells stay gone.


This is the key limit behind the word "permanent." It can describe the destroyed target cells, but it does not promise one fixed shape for life. Weight gain can change the cells that remain. Fullness close to the treated spot can also change what you see later.


Surgical contouring is not suitable for everyone


Neck lifts and tumescent neck liposuction are invasive options for the chin and neck. Some people with existing health problems are not good candidates for them.


An injection is not an automatic match when surgery is ruled out. Ideal candidates for deoxycholic acid have unwanted under-chin fullness mainly caused by pre-platysmal fat. Neck lift and neck liposuction have their own health limits, so each option has a separate test of fit.


If you are also wondering about muscle-relaxing injections, our article explains what Botox can and cannot address in a double-chin concern. That is a different treatment question from whether deoxycholic acid fits under-chin fat.


Our North York option is specific to double-chin treatment


At ReJoo Clinic, our North York double-chin service includes deoxycholic-acid treatment with BELKYRA. It gives Toronto-area patients a local option for this specific under-chin concern. The service is consultation-led and concerns non-surgical chin contouring with this fat-dissolving drug.


If fullness under your chin is the concern, read about our BELKYRA double-chin treatment in North York. It covers the treatment process, recovery and side effects, results and duration, and BELKYRA versus liposuction. You can see the drug and treatment area before you decide whether to speak with us. When you are ready, book a consultation to discuss whether your under-chin fullness and goals fit this option.

Ready to take the next step?

Book a personalized consultation with our medical team to find the right approach for your skin, health, and goals.

©2026 Rejoo Clinic Inc. All rights reserved.

bottom of page