Low blood sugar is called hypoglycemia. A blood sugar level below 70 mg/dL (3.9 mmol/L) is low and can harm you. A blood sugar level below 54 mg/dL (3.0 mmol/L) is a cause for immediate action.
You are at risk for low blood sugar if you have diabetes and are taking any of the following diabetes medicines:
You are also at increased risk of having low blood sugar if you have had previous low blood sugar levels.
Know how to tell when your blood sugar is getting low. Symptoms include:
Sometimes your blood sugar may be too low even if you do not have symptoms. If it gets too low, you may:
Some people who have had diabetes for a long time stop being able to sense low blood sugar. This is called hypoglycemic unawareness. Ask your health care provider if wearing a continuous glucose monitor and sensor can help you detect when your blood sugar is getting too low in order to help prevent symptoms.
Talk with your provider about when you should check your blood sugar every day. People who have low blood sugar need to check their blood sugar more often.
The most common causes of low blood sugar are:
Preventing low blood sugar is better than having to treat it. Always have a source of fast-acting sugar with you.
Do not drink alcohol without eating food. Women should limit alcohol to 1 drink a day and men should limit alcohol to 2 drinks a day. Family and friends should know how to help. They should know:
If you have diabetes, always wear a medical alert bracelet or necklace. This helps emergency medical workers know you have diabetes.
Check your blood sugar whenever you have symptoms of low blood sugar. If your blood sugar is below 70 mg/dL, treat yourself right away.
1. Eat something that has about 15 grams (g) of carbohydrates. Examples are:
2. Wait about 15 minutes before eating any more. Be careful not to eat too much. This can cause high blood sugar and weight gain.
3. Check your blood sugar again.
4. If you do not feel better in 15 minutes and your blood sugar is still lower than 70 mg/dL (3.9 mmol/L), eat another snack with 15 g of carbohydrates.
You may need to eat a snack with carbohydrates and protein if your blood sugar is in a safer range -- over 70 mg/dL (3.9 mmol/L) -- and your next meal is more than an hour away.
Ask your provider how to manage this situation. If these steps for raising your blood sugar do not work, contact your provider right away.
If you use insulin and your blood sugar is frequently or consistently low, ask your provider or nurse if you:
Do not make any changes without talking to your provider or nurse first.
Sometimes hypoglycemia can be due to accidently taking the wrong medicines. Check your medicines with your pharmacist.
If signs of low blood sugar do not improve after you have eaten a snack that contains sugar, have someone drive you to the emergency room or call 911 or the local emergency number. Do not drive when your blood sugar is low.
Get medical help right away for a person with low blood sugar if the person is not alert or cannot be woken up as this is a medical emergency.
American Diabetes Association Professional Practice Committee. 6. Glycemic Goals and Hypoglycemia: Standards of Care in Diabetes-2024. Diabetes Care. 2024;47(Suppl 1):S111-S125. PMID: 38078586 pubmed.ncbi.nlm.nih.gov/38078586/.
Cryer PE, Arbeláez AM. Hypoglycemia. In: Melmed S, Auchus RJ, Goldfine AB, Koenig RJ, Rosen CJ, eds. Williams Textbook of Endocrinology. 14th ed. Philadelphia, PA: Elsevier; 2020:chap 38.