Conventional hydrogels often suffer from weak mechanical properties and display brittle and unstable behaviour limiting their scope for load-bearing applications. Such networks consist of functionalized polymers with covalent cross-links at fixed positions along the polymer backbone, their energy being on the order of 80 kcal/mol for a standard carboncarbon bond (Figure ). Upon deformation, tensile stress is concentrated on the closest neighbouring crosslinks, eventually leading to their rupture and material failure. Increasing the toughness of conventional hydrogels is often attempted by making longer network strands, which however reduces stiffness and fracture strength of the gels. To fabricate hydrogels that are stiff and tough at the same time, mechanisms to dissipate energy are essential, since they allow the gel to reversibly recover from a mechanical impact. Hence, designing high-performance hydrogels requires molecular strategies to enable efficient energy dissipation throughout the hydrogel network. Energy dissipation is often achieved through the introduction of sacrificial bonds, which occur in two categories: (i) a second more brittle network is polymerized within a first loosely cross-linked network (double networks) or (ii) cross-links are made from supramolecular transient interactions, which can be reversibly broken and reformed (Figure ). In the first case, the material is stretched and a share of the bonds in the second, more brittle network are broken leading to an increased dissipation of the energy from mechanical impact. In the second case, the sacrificial bonds are of non-covalent nature and can reversibly break and reform. Non-covalent interactions include, but are not limited to, metal-ligand, ionic interactions, hydrogen bonding, microphase separation and hydrophobic interactions, polymer-nanomaterial adsorption, host-guest complexation, or supramolecular self-assembly. As we will later see, cutting-edge materials often combine both sacrificial bond categories as well as multiple non-covalent interactions to maximize the energy dissipation in the network. However, first we briefly discuss the most frequent modes of energy dissipation at hand.