The use of hyaluronic acid in aesthetic medicine has been in the public domain since at least 1996 and several companies, particularly in recent years, have introduced a multitude of products using increasingly advanced technology thus guaranteeing medical operators increasingly satisfying revitalisation and filling treatments. Indeed, the initial problem with reabsorbable fillers was the inverse relationship between lasting effects and safety: increasing cross-linking in the product, very often increased the frequency of adverse reactions such as oedema and granulomas; conversely, decreasing cross-linking caused a drastic reduction in the duration of the implants.