Collagenase clostridium histolyticum, or QWO®, is a clear, odorless, water-like mixture that is injected through tiny needles into the dimples associated with cellulite on the buttocks. Collagenase clostridium histolyticum is used as a collagenase injection combining two enzymes that degrade specific collagen structures such as the fibrous septae bands that attach skin to underlying muscle and are thought to contribute to the visual dimpling effect of cellulite. Collagenase clostridium histolyticum was granted FDA approval in 2020 for the treatment of moderate to severe cellulite of the buttocks. It is currently available only through prescription under the brand name QWO®.⁴

Collagenase injections contain enzymes that degrade specific types of collagen to weaken collage-based fibrous bands under the skin associated with a variety of medical conditions. Collagenase injections for esthetic purposes are fairly new, but the first collagenase histolyticum injection was granted FDA approval in 2010 to weaken fibrous bands associated with a deformity of the hand. In 2020 a collagenase injection of collagenase clostridium histolyticum was approved under the name QWO® for the treatment of moderate to severe cellulite of the buttocks.⁵

There is no anesthesia needed when administering collagenase injections as the procedure is relatively painless. The needles used are very small and the injection site, the buttocks, is not particularly sensitive. Some practitioners may administer a numbing treatment to the area prior to administering the collagenase injections.

Collagenase clostridium histolyticum and Kybella® are often confused because both involve the injection of an enzyme for body contouring effects and both may be used for the buttocks. The difference between the two lies in the structures they target; Kybella® dissolves fat cells while Collagenase clostridium histolyticum, or QWO®, degrades specific fibrous structures called fibrous septae which are believed to cause the dimpling effect seen in moderate to severe cellulite.