Hypoglycemia hypoglycæmia or low blood sugar (not to be confused with hyperglycemia) is an abnormally diminished content of glucose in the blood.[1] The term literally means “under-sweet blood” (Gr. υπογλυκαιμία, from hypo-, glykys, haima). It can produce a variety of symptoms and effects but the principal problems arise from an inadequate supply of glucose to the brain, resulting in impairment of function (neuroglycopenia). Effects can range from mild dysphoria to more serious issues such as seizures, unconsciousness, and (rarely) permanent brain damage or death.