Lipolysis injections are cosmetic treatments that dissolve small pockets of fat by destroying fat cells with a chemical solution injected directly into the tissue. The active ingredient in the most well-known version, Kybella, is deoxycholic acid, a substance your body naturally produces to break down dietary fat. These injections are not a weight-loss treatment. They’re designed for body contouring, targeting stubborn areas of localized fat that resist diet and exercise.
How the Injections Destroy Fat Cells
Deoxycholic acid works like a detergent. When injected into fatty tissue, it rapidly breaks apart the membranes of fat cells, causing them to burst open and die through a process called necrosis. The contents of those destroyed cells, mostly triglycerides and fatty acids, spill into the surrounding tissue and form what researchers describe as a “lipid lake.”
Your immune system then takes over. Within a few days, macrophages (the cleanup cells of your immune system) swarm the area, engulfing the released fat and cellular debris. This triggers noticeable inflammation, which is why swelling after treatment is so common and often significant. By about three months, the acute inflammation fades and the body begins laying down new connective tissue in the treated area. By six months, the inflammatory response has largely resolved and fibrosis (firmer tissue) has replaced what was once fat.
Because the fat cells are physically destroyed rather than simply shrunk, the results are considered permanent in the treated area. Those cells don’t regenerate. However, remaining fat cells elsewhere can still expand with weight gain.
What Kybella Is Approved to Treat
Kybella (called Belkyra in Canada) is the only fat-dissolving injectable approved by the FDA. Its approval is narrow: it’s only cleared for reducing moderate to severe fat beneath the chin, commonly called a double chin. The FDA has not evaluated or approved deoxycholic acid injections for use anywhere else on the body.
That said, practitioners around the world use lipolysis injections off-label in other areas. Common targets include bra rolls, jowls, small fat deposits on the inner thighs, and localized belly fat. A 14-year study of over 1,200 patients found the injections showed particular efficacy on facial fat and bra rolls, especially in younger patients. The procedure works best on small, soft, easily compressible fat deposits of up to about 500 milliliters in volume. It is not effective for large areas of fat or for treating obesity.
Other Formulations on the Market
Kybella isn’t the only lipolysis injection product in use globally. Aqualyx, widely available in Europe and parts of Asia, uses a different formulation to break down fat cells, which the body then metabolizes and eliminates naturally. Some practitioners use a combination of phosphatidylcholine and deoxycholate, a formulation that has been studied for over a decade in clinical settings. These products are not FDA-approved in the United States, and the FDA has specifically warned that using fat-dissolving injections that lack approval can be harmful.
What the Procedure Feels Like
During a session, the practitioner marks the treatment area and delivers multiple small injections in a grid pattern. For submental (under-chin) treatments, this typically involves two to three vials of solution per session. The injections themselves cause a burning or stinging sensation that most people describe as moderate.
The real discomfort comes afterward. Swelling at the injection site occurs in about 87% of patients, and bruising affects roughly 72%. The swelling can be dramatic, particularly under the chin, where it may take a week or more to subside. Many people plan to take several days off from public-facing activities.
Most people need more than one session to achieve their desired result. Sessions are spaced at least a month apart, and it can take up to three months after a treatment session before the full effect becomes visible, because the body needs time to clear the destroyed fat cells. A complete treatment course for the double chin area often involves two to six sessions.
Side Effects and Risks
Swelling and bruising are essentially guaranteed. Beyond those, the most significant risk specific to chin treatments is injury to the marginal mandibular nerve, which controls muscles around the mouth. This occurred in about 4% of patients during clinical trials and showed up as an uneven smile or weakness on one side of the face. In all reported trial cases, the nerve injury resolved on its own over time, but it can be alarming while it lasts.
Other potential side effects include numbness, firmness, or small lumps in the treated area. These typically resolve within weeks to months. Because deoxycholic acid destroys cells indiscriminately within its reach, precise injection technique matters. Injecting too superficially can damage skin, and injecting near important structures like nerves or blood vessels increases the risk of complications.
Who Is a Good Candidate
Lipolysis injections work best for people who are near their goal weight but have a specific pocket of fat they want to reduce without surgery. Good skin elasticity helps, because the skin needs to contract as the fat beneath it disappears. People with loose or sagging skin may find that removing the fat volume worsens the appearance rather than improving it.
The procedure is not appropriate for everyone. Contraindications include allergy to eggs or soy (relevant for formulations containing phosphatidylcholine), active skin infections in the treatment area, use of blood-thinning medications, compromised immune function, untreated thyroid disorders, polycystic ovary syndrome, and pregnancy or breastfeeding. Perhaps the most important screening factor is realistic expectations. These injections produce subtle contouring, not dramatic transformation.
Cost Per Session
In the United States, a single Kybella treatment session averages $1,640, with prices ranging from about $1,267 to $3,215 depending on location and provider experience. A single vial averages $640 (ranging from $492 to $1,150), and most sessions require two to three vials. Since multiple sessions are typical, total treatment costs often land between $3,000 and $8,000 or more. Cosmetic procedures like this are not covered by health insurance.