Injectable deoxycholic acid, the fat-melting injection, reduced fat under the chin more than placebo in a meta-analysis of randomized controlled trials[1]. That evidence base has limits, because only two of five included trials had a low risk of bias, all showed potential industry bias, and the certainty of evidence was rated low to moderate[2]. A systematic review of non-invasive fat reduction studies found that every available method of measuring the results had significant limitations[3].
This guide walks through what the research says about each approach, what the side effects look like, and why invasive procedures such as liposuction and neck lift still play a significant role in reducing fat under the chin[4].
This article was researched and written with AI assistance from peer-reviewed sources, and automatically fact-checked against those sources. It has not been reviewed by a physician. It is educational, not medical advice. Please consult a board-certified surgeon about your situation. How we write.
Last updated: October 24, 2026
Fat-melting injections use deoxycholic acid, a secondary bile acid that causes fat cells to break apart (lysis) when it is injected into the fat layer under the skin[5]. In the body, deoxycholic acid normally helps emulsify and dissolve dietary fat[5].
Deoxycholic acid was the first lipolytic, or fat-dissolving, substance approved by the US Food and Drug Administration for reducing fat under the chin[6]. Deoxycholic acid injection is described as the only injectable drug approved in the United States and Canada for reducing moderate or severe submental fat (fat below the chin) in adults[7].
Deoxycholic acid injections reduced fat under the chin in several phase III, multicenter, randomized, double-blinded trials[8]. A review counted five phase III, multicenter, randomized, double-blinded trials enrolling more than 1700 patients that showed efficacy on validated rating scales and objective measurements[8].
Objective evidence for the injections came from skin caliper measurements and magnetic resonance imaging (MRI) scans of the fat under the chin[8]. A meta-analysis of five randomized controlled trials with 1,838 participants found greater improvement with deoxycholic acid than with placebo on every efficacy measure studied[1].
A separate systematic review of six studies covering 3488 patients reported a reduction in fat under the chin in every study, with higher patient satisfaction than in the control groups at the end of a 12-week period[9]. The benefits in phase III trials generally came without worsening skin laxity and were largely maintained over extended follow-up, such as two years after treatment[5].
A meta-analysis of randomized trials found that all of the eligible studies showed a potential industry sponsorship bias[2]. The same meta-analysis rated the certainty of evidence as low to moderate, while still concluding that deoxycholic acid is effective for reducing fat under the chin[2].
Side effects of deoxycholic acid injections are very common but usually short-lived and confined to the treated area[8]. Pain at the injection site was the most common adverse event, occurring in more than 80% of treated patients[8]. Other common adverse events were swelling, bruising, numbness and induration, or firmness of the tissue[8].
In randomized trials, adverse events from deoxycholic acid were mostly at the injection site, mostly transient, and commonly resolved within the interval between treatment sessions[1]. Compared with placebo, patients treated with deoxycholic acid had a higher risk of fibrosis, pain, redness, numbness, swelling, itching, nodules, headache and abnormal skin sensations[2].
Complications including skin necrosis (tissue death), nerve injury, hair loss and vascular events can occur and can demand complex management without specific protocols[6].
An analysis of a US Food and Drug Administration adverse event database included thirteen reports describing twenty-one events after deoxycholic acid injections under the chin[10]. Those events included excessive swelling, weakness of the marginal mandibular nerve, a facial nerve, unsatisfactory appearance, numbness, difficulty swallowing, infection and skin necrosis[10]. Two patients in that analysis needed hospital care for skin necrosis, and both had underlying systemic diseases[10].
A review of serious adverse events after these injections in real-world settings described most of them as procedure related and avoidable[11]. Safe injection requires detailed knowledge of the anatomy under the chin to minimize adverse events[8].
If you notice skin darkening or breaking down, trouble swallowing, a lopsided smile, fever or rapidly worsening swelling after an injection, contact your surgeon or treating clinician right away, or call emergency services if symptoms are severe.
Deoxycholic acid is not suitable for every person with fat under the chin, so careful patient selection is key to the result[5]. A review of serious adverse events notes that surgery is preferable for jowling caused by sagging, displaced tissue, while fat-reducing injections are contraindicated for jowling caused by thinning of the tissue under the skin[11].
Deoxycholic acid injection is approved only for fat under the chin, although many cosmetic surgeons use it off-label in other body areas[12]. A systematic review of off-label use found ten relevant articles, covering areas such as the face, bra line, foot and hip and buttock (gluteotrochanteric) region, and called for larger studies[12].
A small study found that a non-surgical diode laser reduced fat on the inner knees[13]. In that study of 19 women with fat on the inner knees, a single session of a 1060-nm diode laser significantly reduced knee circumference at one, three and six months compared with baseline[13].
Fat thickness at the inner knee, measured by ultrasound, was also significantly reduced at one and six months after the laser treatment[13]. Side effects in that knee study were mild and transient, including mild redness and tenderness[13].
That laser study treated only the inner knees, and all of its subjects were female[13].
Between 2014 and 2020, the US Food and Drug Administration adverse event database held 34 reports about 1,060-nm laser lipolysis, which made up 20.6% of the non-invasive fat and cellulite device reports found[14].
High-intensity focused ultrasound (often called HIFU) and monopolar radiofrequency were among the non-invasive fat and cellulite reduction devices with adverse event reports to the US Food and Drug Administration[14]. That database analysis found 19 reports on high-intensity focused ultrasound, 6 on focused ultrasound and 8 on monopolar radiofrequency among 165 reports about non-invasive fat and cellulite devices[14].
Those report counts need careful reading, because most physicians likely do not regularly report adverse events, and report numbers for any device must be weighed against the total number of procedures performed[14]. The authors note that some reports may be unrelated or unsubstantiated[14].
Before choosing focused ultrasound or radiofrequency, ask the clinician which published studies support that device for your specific treatment area, and how fat reduction was measured.
Cryolipolysis, or fat freezing, is a non-invasive treatment that uses cold temperatures to trigger the death of fat cells[15]. A meta-analysis of eight before-and-after studies involving 206 patients found a mean reduction in fat thickness under the chin of 2.78 mm[15].
In a single-arm study of 36 adults treated on the arms, under the chin or the male chest, cryolipolysis produced a mean reduction of 19.1%, and obese subjects did not benefit[16]. In a study of 15 subjects treated under the chin, a blinded panel correctly identified 60% of before and after photographs, and 12 of 15 subjects were satisfied or very satisfied[17].
A large single-center retrospective study of 287 patients and 1118 procedures reported posttreatment pain in 1.70% and one case of paradoxical adipose hyperplasia, a rare complication seen in 0.09%[18]. A review of cryolipolysis notes that further research is needed on its mechanism and on its efficacy in different treatment areas[19].
Researchers describe cryolipolysis as an accessible alternative to liposuction[19]. One review describes cryolipolysis as offering fat reduction without the need for a lengthy recovery period or major surgery[19]. Deoxycholic acid injections are described as an in-office alternative to liposuction or surgical neck contouring for fat under the chin[10].
Invasive procedures such as liposuction and neck lift still play a significant role in reducing fat under the chin[4]. Body mass index was the only factor linked with results in one cryolipolysis study, and obese subjects did not benefit from that treatment[16].
A systematic review found that photographs were subjective, circumference and caliper measurements were confounded, ultrasound depended on the operator, and MRI was expensive when used to measure non-invasive fat reduction[3].
If you are weighing a device or injection against surgery, our guides to liposuction versus non-surgical treatments and the limits of nonsurgical liposuction may help. For fat under the chin specifically, see our page on neck liposuction.
A consultation with a board-certified surgeon can help you decide whether a non-surgical option or liposuction better suits your goals. Questions worth asking include:
Injectable deoxycholic acid is approved only for fat under the chin, although many cosmetic surgeons use it off-label in other body areas[12]. A systematic review of that off-label use found ten relevant articles and called for larger studies[12].
In phase III trials, reductions in fat under the chin were largely maintained over extended follow-up, such as two years after treatment[5].
In one cryolipolysis study, body mass index was the only factor linked with results, and obese subjects did not benefit[16]. A board-certified surgeon can help you weigh your options.
A US Food and Drug Administration database held reports about laser lipolysis, high-intensity focused ultrasound and monopolar radiofrequency devices between 2014 and 2020[14]. In a study of a diode laser for inner knee fat, side effects were mild and transient, including redness and tenderness[13].