The present invention provides protease-resistant peptides, methods of making such peptides, as well as compositions comprising protease-resistant peptides and method of treatment utilizing such peptides. Incorporation of alpha-methyl-functionalized amino acids directly into the main chain during standard peptide synthesis via the methodologies described herein has been determined to produce protease-resistant peptides. The preferred alpha-methyl-functionalized amino acid is alpha-methyl-Phenylalanine and the preferred peptide is glucagon-like peptide (GLP-1).
