The present invention relates to a GLP-1 peptide having the following formula, or a pharmaceutically acceptable salt thereof: X-His-Ala-Glu-Gly-Thr-Phe-Thr-Ser-Asp-Val-Ser-Ser-Tyr-Leu-Glu-Gly-Gln-Ala- -Ala-Lys-Glu-Phe-lle-Ala-Trp-Leu-val-Lys-Gly-Arg-Y (SEQ ID NO. 1) wherein X is a rigidifying hydrophobic moiety and wherein Y is selected from the group consisting of OH, NH.sub.2 and Gly-OH. Moreover, the present invention relates to pharmaceutical compositions comprising a therapeutically effective amount of a peptide of the present invention, or a pharmaceutically acceptable salt thereof, in association with at least one constituent selected from a pharmaceutically acceptable carrier, diluent, and excipient.