Hydrogel compositions comprise an aqueous dispersion phase and a plurality of peptides, or derivatives, or analogues thereof. Each peptide comprises at least two amino acid residues and an aromatic stacking ligand and the hydrogel is formed by self-assembly of said peptides in said aqueous dispersion medium. The aqueous dispersion phase is physiologically acceptable and may have a pH of 6 to 8, as may the hydrogel itself. The hydrogel may be used for cell culture or for treatment of medical conditions characterized by tissue loss/damage.