AbstractIn the last decade, the increasing environmental awareness among scientists brought out green innovations and adequate exploitation of natural resources in corrosion inhibition technology. Herein, the phenolic extract of the Lycium ferocissimum Miers fruit plant was prepared and tested at various stages of maturity as a corrosion inhibitor on commercial carbon steel in an acidic medium (HCl,1 M). The main components of L. ferocissimum extracts were identified by high‐performance liquid chromatography‐electrospray ionization mass spectrometry (HPLC‐MS/ESI). Nine phenolic compounds were found in the extract and the richness in polyphenol content was found in the first stage of maturity. The inhibition performance and mechanism were investigated using potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and weight loss measurements. Assay results revealed similar values in inhibition percentages, around 80 % at an extract concentration of 100 ppm. The inhibition efficiency was critically dependent on the stage of maturity and extractive solvent. Both electrochemical and loss measurements demonstrated that the first stage of maturity displays the highest corrosion inhibition effectiveness and the ethanolic extract presents the strongest active properties.