Kybella is a prescription injection of deoxycholic acid that the FDA has approved for one cosmetic use: improving the appearance of moderate to severe fullness from fat under the chin (submental fat) in adults. It is not a general treatment for excess fat elsewhere on the body, and the FDA has added warnings about serious reactions when it is used in other areas of the body.
What is Kybella?
Kybella is the brand name for an injectable form of deoxycholic acid, its active ingredient. The American Society for Dermatologic Surgery (ASDS) notes that deoxycholic acid is also a bile acid the body makes naturally to help break down and absorb fat from food. According to its FDA prescribing information, it is a cytolytic drug: when injected into fat under the chin, it destroys the membranes of fat cells. Cleveland Clinic and MedlinePlus describe it in plain terms as a medicine that breaks down fat cells to improve the appearance of a "double chin." ASDS calls this submental fullness and notes that some people find it hard to improve with diet and exercise.
The FDA first approved Kybella in 2015. Its label limits the approved use to the submental area in adults and states that it is not approved for fat outside that region and that such use is not recommended. Kybella should be given by a health care provider.
What is the Kybella treatment process like?
Before each session, the label tells the provider to feel the area to confirm there is enough fat in the right layer to treat. The provider then outlines the treatment area under the chin and marks a grid of injection points about 1 cm apart. Small amounts of medicine go into the fat beneath the skin, up to 50 injections per session. The label notes that ice or cold packs and local numbing medicine may be used for comfort.
Swelling is expected. ASDS says the most noticeable swelling can last about 5 to 14 days, and small areas may stay swollen for 4 to 6 weeks. The fat that is broken down is cleared by the body over the following weeks, so any change is gradual.
The FDA label allows up to six treatment sessions, spaced at least one month apart. It also says the number of injections and sessions should be tailored to each person's chin fat and treatment goals. Your Kybella treatment plan, including whether to treat at all, depends on an examination and on how the area responds. No article can predict an individual result.
Who may not be a good candidate?
Fullness under the chin can have causes other than chin fat. The label tells providers to screen for other causes, such as an enlarged thyroid or swollen lymph nodes, before treatment.
Skin quality matters too, because Kybella reduces fat, not loose skin. The label tells providers to weigh the risks in people with excessive skin laxity, prominent neck bands or other features for which reducing fat might give an unwanted look. People in the main clinical trials did not have excessive skin laxity. Part of the exam is deciding whether you have good skin elasticity or whether loose skin is a bigger part of the fullness.
Kybella should not be used when there is an infection in the injection area. The label advises avoiding it in people with current or past trouble swallowing, and using caution in people with bleeding problems, people taking blood thinners or antiplatelet medicines, and people who have had surgery or cosmetic treatment under the chin. Safety and effectiveness have not been established in people under 18, and there are no adequate studies in pregnancy. Tell your provider if you are pregnant, planning a pregnancy or breastfeeding.
What did Kybella results look like in clinical trials?
The FDA approval rests on two placebo-controlled trials in adults aged 19 to 65 with moderate or severe fullness under the chin. Participants could receive up to six sessions at least one month apart, and 59% received all six. Results were rated 12 weeks after the final session by both the clinician and the participant.
- An improvement of at least one grade on both ratings occurred in 70.0% and 66.5% of Kybella-treated participants, compared with 18.6% and 22.2% on placebo.
- An improvement of at least two grades on both ratings was less common: 13.4% and 18.6% with Kybella, compared with less than 0.1% and 3.0% on placebo.
- In a group measured by MRI, 43% of Kybella-treated participants had at least a 10% reduction in fat volume under the chin, compared with 5% on placebo.
These are group findings from studies with set entry criteria. In these trials, most treated participants had at least a one-grade change, and far fewer had a two-grade change. The numbers cannot tell you how your own chin will respond.
What side effects can happen?
In clinical trials, most people had reactions at the injection site. The most common included swelling, bruising, pain, numbness, redness and areas of firmness. Some of these, including numbness, swelling, pain and firmness, lasted more than 30 days in a portion of trial participants.
Less common but important risks listed on the label include:
- Injury to a facial nerve near the jaw, which can cause an uneven smile or facial muscle weakness. In trials, these cases resolved without additional treatment, though some lasted several months.
- Trouble swallowing, usually alongside swelling and pain under the chin.
- Hair loss in the treated area, which may persist.
- Skin sores, tissue damage, infection, and lumps or masses at the injection site. Some lumps and masses may not go away on their own and may need medical treatment.
- Allergic reactions such as rash, hives or itching, and injury to a blood vessel if medicine is accidentally injected into an artery or vein.
Why does treatment outside the chin area matter?
In September 2026, the FDA announced new warnings in Kybella's labeling about serious adverse reactions after use outside the approved area under the chin. The agency reported cases that included blurred or reduced vision after injection around the eyes, muscle and nerve injury, facial weakness, and nodules or masses that did not resolve.
Using Kybella anywhere other than the submental area is off-label, and the label states that such use is not recommended. If a provider suggests deoxycholic acid for another body area, ask directly whether the use is approved and what is known about its risks.
When should you call your provider or get emergency care?
MedlinePlus advises calling your doctor right away about difficulty swallowing, pain or tightness in the face or neck, an uneven smile or facial weakness, or signs of infection at the injection site such as spreading redness, sores or drainage. Report persistent hard lumps or hair loss to your provider. Seek immediate medical care for any new vision change; sudden vision loss needs emergency evaluation.
Get emergency care for trouble breathing, swelling of the throat, or a severe allergic reaction. Follow the written aftercare instructions from your treating provider, and make sure they know about any medicine you take that affects bleeding.
Questions to ask at a Kybella consultation
- Is the fullness under my chin caused by fat, or could something else be involved?
- Would loose skin or neck bands affect how my result might look?
- What would my Kybella treatment plan look like, and how will we decide whether to continue?
- Which reactions should I expect, and how long might swelling or numbness last?
- Which symptoms should prompt a same-day call or emergency care?
- Do my medicines, past procedures or health history change the plan?
Prepare with the consultation checklist, explore facial aesthetics at Anew Laser MD, or use the contact page to ask whether Kybella is offered at your location. Individual results vary.
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General educational information is not a diagnosis or treatment recommendation. Consult a qualified clinician about your individual circumstances.