ABSTRACT
Injections of hyaluronic acid (HA) filler for soft tissue augmentation and facial rejuvenation can be considered the second most common non-surgical aesthetic practice since 2019, accounting for about 4.3 million clinical procedures worldwide, reaching a 16% increase over the previous year. Any HA filler employed in aesthetic medicine is typically made of biochemically crosslinked hyaluronan molecules, often resulting in a kind of hydrogel, which may prevent further enzymatic degradation, leading to a longer duration and endowed with an improved rheologic property when compared with uncrosslinked HA. Any physicochemical and rheological property of HA fillers may affect their performance hallmarks, including tissue targeting and integration, lift capability, resistance, and deformability, which alongside different techniques of injection and the same nature of fillers, should affect any outcome in the clinical setting. The market of HA has been valued at 8.5 billion USD in 2020 and is forecasted to reach a compound annual growth rate of 7.19% by 2028, starting in 2021.
