T1D glossary

Level 3 hypoglycemia

Also called severe hypoglycemia, level 3 low.

Level 3 hypoglycemia is a severe low in which the person's thinking or movement is affected so much that someone else has to help them recover. It is defined by that need for help, not by a number. Glucagon is the treatment when the person cannot eat or drink. (ADA Standards of Care 2026, section 6)

Worked example

A teen at 45 mg/dL (2.5 mmol/L) who drinks juice on their own has a level 2 low. A teen at 60 mg/dL (3.3 mmol/L) who is too confused to drink and needs a parent to give glucagon has a level 3 low.

Related terms

• Level 2 hypoglycemia
• Glucagon
• 15-15 rule

Sources, quoted

• ADA Standards of Care 2026, section 6: “Lastly, level 3 hypoglycemia is defined as a severe event characterized by altered mental and/or physical functioning that requires assistance from another person for recovery, irrespective of glucose level.”
• ADA Standards of Care 2026, section 6: “The use of glucagon is indicated for the treatment of hypoglycemia in people unable or unwilling to consume carbohydrates by mouth.”

Every quote above is checked against its source page before each update of this site; last checked 2026-10-06. The worked example is our own arithmetic. This page explains a term; it is not advice for a person's treatment.