Doctor’s Best PepZin GI Zinc L-Carnosine Complex. Zinc L-Carnosine (PepZin GI®) – supports stomach lining integrity. Product: PepZin GI® Zinc L-Carnosine Complex. Who should take PepZin GI?. ✨ Science-based zinc L-carnosine complex designed to support stomach lining integrity, digestive comfort, and overall gut health.