Hyaluronic acid (HA) filler injections have increased in popularity. They are usually performed in combination with other treatment modalities, including lasers and energy-based devices, to enhance cosmetic results. Theoretically, HA and other filler injections should be performed after laser- or energy-based device treatments. In some instances, however, practitioners are asked to administer laser- or energy-based device treatment after HA dermal filler injection. There is a concerning possibility of HA filler degradation as a result of bulk heating generated by lasers or energy-based devices, especially radiofrequency (RF). To evaluate the effect of RF treatment at different time points on HA degradation in vivo, using clinicohistological analysis. Fourteen volunteers were recruited and received intradermal HA filler injections in four sites on the abdomen. One site served as the control, and the other three sites were treated with monopolar RF on the same day after injection, at 14 and 28 days post-injection. Skin biopsies were performed at baseline and 56 days after HA injection. Histopathological sections were reviewed for residual filler in the tissue. The results showed that HA grading scores decreased in five (35.71%), one (7.14%), and one (7.14%) participants when RF was performed immediately, 14 and 28 days after injection, respectively. In conclusion, RF treatment after HA filler injection may affect the integrity of the HA filler in the tissue, especially if RF treatment was performed on the same day after HA injection.