Hypoglycemia is blood sugar that falls below the normal range — commonly defined as under 70 mg/dL. Early symptoms include shakiness, sweating, a racing heart, hunger, and irritability; if it drops further, confusion, blurred vision, and loss of consciousness can follow. It is treated by taking fast-acting carbohydrate (glucose tablets, juice) and rechecking.
GLP-1 medications trigger insulin release only when blood sugar is high, so on their own they rarely cause hypoglycemia. The risk rises substantially when a GLP-1 is combined with insulin or a sulfonylurea, both of which lower blood sugar regardless of what it already is — prescribers often reduce those doses when a GLP-1 is started. See GLP-1s with insulin or sulfonylureas: understanding hypoglycemia risk.