(Low Blood Glucose; Low Blood Sugar)


Hypoglycemia is a low level of glucose in the blood. Glucose is your body's main source of energy. Low levels make it hard for your body to work as it should. This will cause a wide range of problems.


Diabetes medicine is a common cause of hypoglycemia. Other things that can increase the risk of hypoglycemia while taking this medicine include:

  • Taking too much medicine
  • Eating too little at meals, delaying or missing meals
  • Unplanned intense exercise
  • Sickness like cold or flu

Hypoglycemia can also happen in people without diabetes. This is less common. It may be caused by:

  • Alcohol use disorder, heavy drinking and not eating is the worst combination
  • Starvation
  • Early pregnancy
  • Hormone imbalances from some pituitary or adrenal gland problems
  • Certain liver problems
  • Kidney disease
  • Certain types of stomach surgery
  • Tumor that makes insulin
  • Severe illness or infection

Risk Factors

Things that may increase the chance of hypoglycemia are:

  • Medicines that lower blood sugar levels
  • Drinking too much alcohol
  • Fasting (worse when it happens with intense exercise)


Symptoms may start slowly or quickly. It may cause:

  • Sweating
  • Nervousness
  • Lightheadedness
  • Rapid heartbeat
  • Hunger
  • Headache
  • Tingling feeling around the mouth

As hypoglycemia worsens, it may cause:

  • Fatigue
  • Weakness
  • A change in behavior or confusion
  • Poor control of movements
  • Seizure
  • Loss of consciousness

Sensitivity to low blood glucose may change over time. Early symptoms may start to fade if you have a lot of events. This will make it harder to feel when glucose starts to fall.


The doctor may suspect hypoglycemia based on your health and symptoms. Glucose levels can be measured with a quick blood test. A device pricks a finger to draw a drop of blood. A machine will measure the glucose in the blood drop.

Other tests may need to be done if you do not have diabetes. This may include checking your blood glucose levels after fasting.


Treatment will bring blood glucose levels back to normal. Other steps may be needed to keep it from happening again. Quick care can stop further health problems.

Mild Hypoglycemia

Low blood sugar can be increased quickly with:

  • Sugary drink or food such as:
    • Fruit juice
    • Sugared soft drink
    • Table sugar in water
    • Honey or corn syrup
  • Glucose tablets

A snack or meal can then help to keep levels stable.

Severe Hypoglycemia

Very low levels can make someone pass out. Immediate care is needed. Treatment may include:

  • Glucagon—a hormone that raises blood sugar levels
  • IV glucose

Care will be given until blood glucose is stable.

Managing Future Events

Hypoglycemia may happen again in those at risk. To lower risk of more events:

  • Learn what early symptoms are. They can vary from person to person. Take quick steps to fix low blood glucose.
  • Wear a medical alert bracelet or ID.


To help reduce the chance of hypoglycemia:

  • For people with diabetes:
    • Follow treatment plan. This includes medicine, food plan, and activity.
    • Check your blood glucose often.
    • Avoid drinking too much alcohol.


American Diabetes Association
Hypoglycemia Support Foundation


Canadian Diabetes Association


Hypoglycemia (low blood glucose). American Diabetes Association website. Available at: https://www.diabetes.org/diabetes/medication-management/blood-glucose-testing-and-control/hypoglycemia. Accessed February 12, 2020.
Hypoglycemia in diabetes. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/hypoglycemia-in-diabetes/. Updated February 7, 2020. Accessed February 12, 2020.
Hypoglycemia in persons without diabetes. EBSCO DynaMed website. Available at: https://www.dyname.... Updated July 18, 2018. Accessed February 12, 2020.
Low blood glucose (hypoglycemia). National Institute of Diabetes and Digestive and Kidney Diseases website. Available at:https://www.niddk.nih.gov/health-information/diabetes/overview/preventing-problems/low-blood-glucose-hypoglycemia. Updated August 2016. Accessed February 12, 2020.
Last reviewed September 2019 by EBSCO Medical Review Board Marcin Chwistek, MD
Last Updated: 8/26/2020

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