Evidence-graded answer
Does GLP-1 cause low blood sugar (hypoglycemia)?
GLP-1 alone has very low hypoglycemia risk — its insulin-secretion mechanism is glucose-dependent. Hypoglycemia risk rises sharply when GLP-1 is combined with insulin or sulfonylureas; those medications usually need dose reduction at GLP-1 start.
Mechanism: GLP-1 stimulates insulin only when blood glucose is elevated. In non-diabetic patients, hypoglycemia is extremely rare on GLP-1 monotherapy.
In T2D patients on insulin or sulfonylureas (glipizide, glyburide), GLP-1 amplifies their hypoglycemic effect. Common practice: reduce insulin dose 20% at GLP-1 start, hold or cut sulfonylurea by half.
Severe hypoglycemia on GLP-1 monotherapy in non-diabetic patients should prompt evaluation for other causes (insulinoma, cortisol deficiency, malnutrition).