What are the causes of hypoglycemia (low blood sugar)?

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Last updated: May 12, 2025View editorial policy

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From the Guidelines

Hypoglycemia can be caused by numerous factors, and the top 10 causes include excessive insulin administration, skipped or delayed meals, intense physical exercise, certain medications, alcohol consumption, insulinomas, severe liver disease, adrenal insufficiency, kidney disease, and reactive hypoglycemia, as supported by recent studies 1.

Causes of Hypoglycemia

The following are the top 10 causes of hypoglycemia:

  • Excessive insulin administration, which is the most frequent cause in diabetic patients who may accidentally overdose or miscalculate their insulin needs 1
  • Skipped or delayed meals, particularly in individuals who have already taken diabetes medications 1
  • Intense physical exercise without adequate carbohydrate intake, as exercise increases glucose utilization 1
  • Certain medications like sulfonylureas (glipizide, glyburide) that stimulate insulin release 1
  • Alcohol consumption, especially without food, as it inhibits gluconeogenesis in the liver 1
  • Insulinomas, which are insulin-producing tumors of the pancreas that release excess insulin regardless of blood glucose levels 1
  • Severe liver disease, which impairs glycogen storage and gluconeogenesis 1
  • Adrenal insufficiency, where cortisol deficiency reduces the body's ability to maintain normal glucose levels 1
  • Kidney disease, which can affect medication clearance and lead to prolonged insulin action 1
  • Reactive hypoglycemia, occurring within hours after meals due to excessive insulin response 1

Importance of Understanding Causes

Understanding these causes is essential for proper diagnosis and management of hypoglycemia, which typically presents with symptoms like shakiness, sweating, confusion, and in severe cases, loss of consciousness 1.

Recent Studies

Recent studies have shown that bundled preventive therapies, including proactive surveillance of glycemic outliers and an interdisciplinary data-driven approach to glycemic management, can reduce hypoglycemic episodes in the hospital by 56-80% 1.

High-Risk Groups

Certain groups, such as young children with type 1 diabetes, the elderly, and individuals with low annual household incomes, are particularly vulnerable to hypoglycemia and require individualized glycemic goals, patient education, and routine clinical surveillance to improve outcomes 1.

From the FDA Drug Label

The risk of hypoglycemia after an injection is related to the duration of action of the insulin and, in general, is highest when the glucose lowering effect of the insulin is maximal Other factors which may increase the risk of hypoglycemia include changes in meal pattern (e.g., macronutrient content or timing of meals), changes in level of physical activity, or changes to concomitantly administered medication Patients with renal or hepatic impairment may be at higher risk of hypoglycemia Because acarbose given in combination with a sulfonylurea or insulin will cause a further lowering of blood glucose, it may increase the potential for hypoglycemia

The following are 10 causes of hypoglycemia:

  • Changes in insulin regimen
  • Changes in meal pattern
  • Changes in level of physical activity
  • Changes to concomitantly administered medication
  • Renal impairment
  • Hepatic impairment
  • Combination of acarbose with sulfonylurea or insulin
  • Medication errors, such as accidental mix-ups between insulin products
  • Use of beta-blockers, which can block the sympathetic nervous system and reduce symptomatic awareness of hypoglycemia
  • Recurrent hypoglycemia, which can reduce symptomatic awareness of hypoglycemia 2, 3

From the Research

Causes of Hypoglycemia

The following are causes of hypoglycemia:

  • Insulin therapy 4, 5
  • Oral hypoglycemic agent therapy 4, 5
  • Use of drugs known to cause hypoglycemia, such as:
    • Propranolol 4
    • Salicylates 4
    • Disopyramide 4
    • Sulfonylurea 5, 6
  • Alcohol consumption 4
  • Sepsis 4
  • Chronic malnutrition 4
  • Acute caloric deprivation 4
  • Concomitant liver disease 4
  • Congestive heart failure 4
  • Associated endocrine deficiency 4
  • Deficiency of precursors of gluconeogenesis, such as alanine 4
  • Deficient gluconeogenesis 4
  • Impaired glycogenolysis 4
  • Diminished renal gluconeogenesis 4
  • Impaired renal insulin degradation and clearance 4
  • Poor nutrition 4
  • Deficiency in an immediate counterregulatory hormone, such as catecholamine and glucagon 4
  • Dialysis 4, 7, 8
  • Renal failure 4, 7, 8
  • End-stage renal disease (ESRD) 7, 6, 8
  • Chronic kidney disease (CKD) 6, 8

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Hypoglycemia associated with renal failure.

Endocrinology and metabolism clinics of North America, 1989

Research

PATHOPHYSIOLOGY AND MANAGEMENT OF HYPOGLYCEMIAIN END-STAGE RENAL DISEASE PATIENTS: A REVIEW.

Endocrine practice : official journal of the American College of Endocrinology and the American Association of Clinical Endocrinologists, 2017

Research

Novel approaches to hypoglycemia and burnt-out diabetes in chronic kidney disease.

Current opinion in nephrology and hypertension, 2022

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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