The inhibitor system L- glutamic acid - Zn²⁺ has been investigated by electrochemical and gravimetric (weight loss) techniques at room temperature. At pH-7.6, the formulation consisting of L-glutamic acid- Zn²⁺ offers 90% inhibition efficiency (IE). Polarization study reveals that this formulation functions as an anodic inhibitor. AC impedance spectra reveal that a protective film is formed on the metal surface. At isoelectric point (pH-3.1), the IEs of L-glutamic acid and also the L-glutamic acid-Zn²⁺ systems are very low. In some cases there is acceleration of corrosion, -33% inhibition efficiency is noticed (negative IEs). The gravimetric measurements aided in the classical prediction of the corrosion inhibition process.