Not all “filler” is actually doing the same thing—and knowing the difference can save you from booking the wrong injectable. In this installment of The Glossary, we break down the increasingly confusing world of HA fillers, collagen stimulators like Sculptra and Radiesse, and skin boosters like Skinvive, plus why crosslinking matters and how filler differs from Botox and other neuromodulators. We’re also getting into reversibility, longevity, leftover filler, and why the treatment you think you want may not be what a great injector recommends. Consider this your beauty-editor cheat sheet before your next consultation.