Lipolysis injections are cosmetic treatments that dissolve small pockets of fat by destroying fat cells directly under the skin. The only FDA-approved version is Kybella (deoxycholic acid), which is specifically approved for reducing fat under the chin in adults. Other compounded formulations exist and are used off-label on various body areas, but none have received FDA approval.
These injections are not a weight-loss tool. They’re designed for people who are near their goal weight but have stubborn fat deposits that don’t respond to diet or exercise, particularly the submental fullness commonly called a “double chin.”
How the Injections Destroy Fat Cells
The active ingredient in Kybella, deoxycholic acid, is a bile salt your body naturally produces to break down dietary fat. When injected into fatty tissue, it works like a detergent: it dissolves the outer membrane of fat cells, causing them to rupture and die almost immediately. This process is called adipocytolysis.
What happens next follows a predictable biological sequence. Within the first few days, the contents of the destroyed fat cells pool together, forming what researchers describe as “lipid lakes,” collections of released fats surrounded by immune cells called macrophages. By about a week, macrophages are actively consuming the fat debris. Over the following weeks, these immune cells form clusters around the remaining dead cells and gradually clear them out. The entire cleanup process takes roughly three months, which is why visible results aren’t immediate.
Once fat cells are destroyed, they don’t regenerate. The reduction in that specific area is considered permanent, assuming your weight remains stable.
What Treatment Looks Like
A typical session involves multiple small injections spaced across the treatment area. For submental fat, the provider maps out a grid pattern under the chin and injects at each point. The procedure itself takes about 15 to 30 minutes.
Some people are satisfied after a single session, while others need two or three treatments to reach their goal. Follow-up sessions are spaced a few weeks apart so the body has time to process each round of cell destruction. In clinical trials for Kybella, patients received up to six treatments.
The average cost of nonsurgical fat reduction is $1,157 per session, according to the American Society of Plastic Surgeons. Since it’s cosmetic, insurance does not cover it.
Effectiveness in Clinical Trials
In phase 3 clinical trials, 64.4% of men treated with deoxycholic acid achieved at least a one-grade improvement on a standardized facial fat rating scale, compared to just 8.6% of those who received a placebo. Nearly 10% of treated patients achieved a two-grade improvement, while no one in the placebo group did. Results for women followed a similar pattern. These aren’t dramatic transformations, but for a targeted area like the chin, a one- or two-grade change is often the difference between visible fullness and a defined jawline.
Side Effects and Recovery
Because the injection literally destroys cells, your body mounts an inflammatory response. That means swelling, and it can be significant. In clinical trials, the median duration of swelling was 9 to 10 days. Pain at the injection site typically lasted about a day. Numbness and firmness (induration) in the treated area were more persistent, lasting 17 to 25 days on average. Bruising is also common.
The most notable risk specific to chin treatment is temporary injury to the marginal mandibular nerve, which controls movement in the lower lip and chin. This occurred in 4.3% of patients in clinical trials, causing temporary weakness or an uneven smile. The median duration was 31 days, and it resolved on its own in the vast majority of cases.
With compounded formulations containing phosphatidylcholine and sodium deoxycholate (often called PCDC), the side effect profile is similar: pain and swelling lasting about 48 hours, with bruising persisting up to 10 days.
FDA Approval and Off-Label Use
Kybella is the only fat-dissolving injectable drug with FDA approval, and that approval covers one area only: under the chin. The FDA has not evaluated it for use anywhere else on the body.
Despite this, many cosmetic clinics offer lipolysis injections for the abdomen, love handles, thighs, upper arms, bra fat, and other areas. These treatments typically use compounded PCDC formulations that are not FDA-approved. The FDA has specifically warned that using fat-dissolving injections that lack approval “can be harmful.” The concern is straightforward: without rigorous clinical trials for those body areas, the safety profile and effectiveness are not well established.
This doesn’t mean off-label treatments never work, but it does mean you’re accepting more uncertainty about both results and risks. If a provider offers lipolysis injections for body areas beyond the chin, ask specifically what product they’re using and whether it has regulatory approval.
Who Is a Good Candidate
The best candidates are people at or near a healthy weight who have a localized pocket of fat they want reduced. For chin treatment specifically, you also need reasonable skin elasticity. When fat cells are destroyed, the overlying skin needs to tighten and conform to the new contour. If your skin has significant laxity, whether from aging, weight fluctuations, or genetics, the result may be loose skin rather than a smoother profile.
People with active infections in the treatment area, prior surgery that changed the chin anatomy, or difficulty swallowing are generally not candidates for submental injections. Lipolysis injections are also not appropriate as a substitute for weight loss. They remove a small volume of fat cells in a targeted zone, not the kind of distributed fat reduction that comes from changes in diet or exercise.
If you’re considering treatment beyond the chin, the same skin elasticity principle applies. Poor elasticity increases the chance of sagging skin after fat removal, particularly in areas like the abdomen, where skin has been stretched by pregnancy or significant weight changes. In those cases, providers may recommend skin-tightening procedures alongside or instead of injections.