Amyloidogenic peptides are often associated with disease, however some can also form functional amyloids. One such example is the peptide hormone glucagon-like peptide-1 (GLP-1), which consists of either 30 or 31 amino acids. Produced mainly in the intestines, GLP-1 plays a crucial role in regulating glucose metabolism. Due to its short half-life in vivo, it is believed to be stored as a stable inactive amyloid within endocrine secretory granules (pH ~5.5) and transformed into its active monomeric form post-secretion (pH ~7.4) through a pH shift. Taking advantage of its metabolic effects, GLP-1 and associated analogues (e.g. Ozempic (semaglutide)) have emerged as pharmaceutical agents for the treatment of type 2 diabetes mellitus, obesity and related conditions. These analogues often are designed to last longer in the body to increase efficacy and reaction time. Studies have shown that GLP-1 can form amyloid fibrils not only at low pH but also under physiological pH if not degraded by enzymes. The structure of GLP-1 amyloid fibrils at low or physiological pH has yet to be determined, but it’s hypothesized that these two structures are different. Therefore, the structure and possible toxicity of fibrils at these two pH values is of interest in light of the increased lifetime of GLP-1 analogues in vivo. We have begun by investigating the formation of GLP-1 fibrils at both pH 5.5 and pH 7.4 utilizing a thioflavin T fluorescence assay, negative-stain TEM and initial high resolution structural characterization using cryo-electron microscopy (cryo-EM). These studies offer preliminary insights into the assembly and disassembly pathways, amyloid stability, and potential pathological implications of GLP-1 fibrils.