Three different inhibitors have been tested in a two-phase laboratory flow loop system with carbon steel tubes under conditions near a European gas well with a gas-liquid ratio of 20000. After a detailed description of the experimental setups degradation rates of material API L-80 as function of flow velocity and inhibitor dosing are presented. Inhibitor 1 was based on ethoxylated phosphate coco-amine salt dissolved in benzene inhibitor 2 was an imidazoline dissolved in ethylene glycol with additions of hexamethylenediamine and thioglycolic acid. Inhibitor 3 exhibits as an active ingredient alkylamine dissolved in ethylene glycol and different alcohols. Analysis of inhibitors was done on the one side with gas chromatography to determine volatile species and on the other side with liquid chromatography to characterize non-volatile species.Results show for all investigated superficial flow velocities in a range between 3 and 35 m/s that alkylamine based inhibitor exhibits the best performance. Dosing with around 50 ppm (addition to the liquid phase) is sufficient to fully protect carbon steel. The imidazoline based inhibitor reaches a high performance by addition of 100 ppm whereas the ethoxylated phosphate coco-amine salt based inhibitor exhibits a critical concentration much higher than 100 ppm to sufficiently protect carbon steel. Tested flow regimes were annular and wavy flow.