Is hypoglycemia life-threatening?

Most of the time no: Hypoglycemia is just the blood sugar dropping down below normal limits. Most of the time this causes symptoms and can be taken care of rapidly. There may be a rare instance in which the blood sugar becomes very low and the person is unaware for many reasons, mainly due to being very ill, etc. Under these rare circunstances it may be life-threatening.

Hypoglycemia: It can be fatal. But usually only in type 1s who go into DKA (diabetic ketoacidosis). But can be serious in any diabetic as your brain shuts down or malfunctions as glucose drops. Low is <70, and a major low is <50. A major low can cause confusion, unconsciousness, seizures, and put you in the ER or hospital . Minor lows tend to cause diaphoresis (cold sweats), shakiness, mouth tingling, etc