The present invention refers to a composition that is useful as a filler for the correction of soft tissue volume loss, for example for the cosmetic treatment of wrinkles, or for the treatment of disorders such as lipoatrophy or lipodystrophy in general, said composition comprising agarose and hyaluronic acid, or a pharmaceutically acceptable salt thereof. The particular interaction that takes place between the two components makes even high concentrations of agarose injectable and tolerable, said high concentrations being particularly useful for ensuring the duration and stability over time of the aesthetic results that are achievable using this filler.