Equilibrium clusters in concentrated lysozyme protein solutions

► The studied lysozyme solutions are dominated by monomers only for ϕ⩽0.012. ► For the strong dilution 70% of proteins are in a form of monomers. ► For ϕ = 0.033 only 20% of proteins do not belong to a cluster. ► For ϕ = 0.12 almost no individual particles exits, and branched, irregular clusters of large extent appear.