Fillers are high-density preparations used to "fill" expression lines. Mesotherapy involves intradermal injection of a whole cocktail of preparations: vitamins, peptides, lipolytics, and amino acids. Hyaluronic acid can be one of many components in mesotherapy, but not the only or main one.
Biorevitalization, on the other hand, involves injecting only low-density hyaluronic acid.
Mesotherapy is more suitable for young skin that doesn't require intense hydration. Mesococktails help maintain excellent skin condition, saturating it with vitamins and other beneficial ingredients.
For ageing skin—after 35, and in some cases even after 30—biorevitalisation is preferable. Biorevitalizants, the preparations used for biorevitalisation, contain a higher percentage of hyaluronic acid and longer chains, thus providing a more powerful moisturising effect.