The active ingredient in Kybella is synthetic deoxycholic acid. Deoxycholic acid is a naturally occurring molecule in the body that aids in the breakdown and absorption of dietary fat. When injected into the fat beneath the chin, Kybella destroys fat cells, resulting in a noticeable reduction in fullness under the chin. Once destroyed, these cells can no longer store or accumulate fat, so further treatment is not expected once you reach your desired aesthetic goal.