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Melissa Hu, MD

Board Certified Facial Plastic Surgeon

It's natural to take steps to look your best
  • Dr. Melissa Hu


Updated: Jun 20, 2018

Kybella is an injectable drug composed of deoxycholic acid which is a naturally occurring acid in the body that helps absorb fat cells. Kybella was FDA approved in 2015 to treat fullness under the chin due to excessive fat. The drug causes lysis (rupture) of fat cells where it is injected that is eventually reabsorbed into the body. The drug can also cause destruction of skin if injected too closely to the skin, so should be used by experienced injectors only. Kybella offers people a nonsurgical method to treat excess fat of the chin and neck regions.

Kybella is ideal for people with hereditary forms of submental fullness or “double chin.” These people typically have more fullness under the chin compared to the rest of the neck that does not completely resolve despite significant weight loss. The most effective results can be obtained in people with mild to moderate forms of submental fat. Kybella can also achieve changes in people with more moderate to severe forms of submental fat, but these changes are often subtler and require a higher number of vials and sessions.

Reasons for less effective results with Kybella may also include severely ptotic submandibular glands (droopy saliva glands that sit under the jaw), low hyoid bone – these people have a less well defined angle of the neck, and excessive fat deep to the platysma neck muscle – Kybella injections deep to this broad brand of muscle causes increased risk to nerve, vessel and muscle damage. Patients in the last group are often identified with more symmetric, diffuse fullness of the chin and neck regions. Schedule a consultation to see if you are a candidate for Kybella.

Each treatment requires anywhere between 1 to 3 vials. The actual number of injections vary between 20 and 60 injection points. Injections can be repeated as early as one month, and the number of sessions required varies based on the severity of submental fat and number of vials used per session – typically requiring 3-6 total treatment sessions. Noticeable results are often seen by the second and third treatment. Because the results are long lasting, retreatment and maintenance is not required. Exceptions to this would be if there was significant weight gain, development of a lipoma in the region, or if skin and muscle looseness became contributing causes for submental redundancy. Each treatment takes about 15 minutes.

Regarding down time, there is no physical down time with Kybella. However, some may suggest social down time, typically for 3 to 4 days after treatment due to resultant redness and swelling. The swelling is due to the process of fat cells swelling to the point of rupture. This process can cause some mild discomfort, tightness, redness, and noticeable swelling in the neck region. Rarely is the discomfort severe enough to warrant treatment with pain medication. The contents of ruptured fat cells are slowly resorbed into the body and can take 3 to 10 days for full resorption.

Side effects from Kybella injections can include bruising, swelling, pain, firm knots and numbness. Bruising occurs as with any trauma with a needle and possible injury to small vessels under the skin. Avoiding aspirin, blood thinners prior to injection and treating with ice and arnica may help. Swelling occurs for reasons as stated above and are typically worst in the first 3 days. Pain has been reported in areas of swelling due to sensation of tightness as well as from development of knots within the fatty tissue. These knots are believed to be injection granulomas which is basically inflammatory scar tissue from injection and injury of fat cells. These granulomas may take 4-8 weeks to resolve. Numbness may result from the effect of swelling that causes rupture of fat cells. The swelling compresses small local nerves and causes numbness until swelling resolves and nerve function is restored. A more serious result of nerve injury may involve damage to the marginal mandibular nerve which runs along the lower border of the jaw and helps pull down the corner of the lip. Knowledge of this region’s anatomy is of utmost importance to prevent serious side effects such as damage to major nerves, glands, muscles and vessels of the face and neck.

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