The tale of protein-surfactant interactions has been the goal of many scientific investigations in the last few decades. The interaction between proteins and amphiphiles in solution are of wide interest due to the ubiquity of these compounds in pharmaceutical formulations and health care products. However, detailed structural models of protein-surfactant complexes are still rather scarce and general consensus is yet missing. The aim of this experiment is to elucidate the mechanism of interaction of human growth hormone with a set of non-ionic surfactants (polysorbate 20, octaethylene glycol monododecyl ether, and dodecylmaltoside) by means of contrast-variation SANS. The main goal will be to identify the characteristics of the surfactant-protein complexes, the effect of the surfactant in the protein conformation and the interactions occurring in each system.