Main influencing factors of GLP-1 secretion. GLP-1 secretion may be modulated by several factors, such as the gut microbiome, eating behavior, glucose tolerance, metabolic profile, sex, medication, and body mass index (indicated by dark blue arrows). GLP-1 also affects these factors (except sex and medication), in addition to its neuroprotective properties (indicated by light blue arrows). GLP-1, glucagon-like peptide 1.