Hypoglycemia (Low Blood Sugar)

Woman drinking glass of milk.

Too little sugar (glucose) in your blood is called hypoglycemia or low blood sugar. Low blood sugar usually means anything lower than 70 mg/dL. Talk with your healthcare provider about your target range and what level is too low for you. Diabetes itself doesn’t cause low blood sugar. But some of the treatments for diabetes, such as pills or insulin, may raise your risk for it. Low blood sugar may cause you to pass out or have a seizure. So always treat low blood sugar right away, but don't overeat.

Special note: Always carry a source of fast-acting sugar and a snack in case of hypoglycemia.

What you may notice

If you have low blood sugar, you may have one or more of these symptoms:

  • Shakiness or dizziness

  • Cold, clammy skin or sweating

  • Feelings of hunger

  • Headache

  • Nervousness

  • A hard, fast heartbeat

  • Weakness

  • Confusion or irritability

  • Blurred vision

  • Having nightmares or waking up confused or sweating

  • Numbness or tingling in the lips or tongue

What you should do

Here are tips to follow if you have hypoglycemia: 

  • First check your blood sugar. If it is too low (out of your target range), eat or drink 15 to 20 grams of fast-acting sugar. This may be 3 to 4 glucose tablets, 4 ounces (half a cup) of fruit juice or regular (nondiet) soda, 8 ounces (1 cup) of fat-free milk, or 1 tablespoon of honey. Don’t take more than this, or your blood sugar may go too high.

  • Wait 15 minutes. Then recheck your blood sugar if you can.

  • If your blood sugar is still too low, repeat the steps above and check your blood sugar again. If your blood sugar still has not returned to your target range, contact your healthcare provider or seek emergency care.

  • Once your blood sugar returns to target range, eat a snack or meal.

Preventing low blood sugar

Things you can do include the following: 

  • If your condition needs a strict treatment plan, eat your meals and snacks at the same times each day. Don’t skip meals!

  • If your treatment plan lets you change when you eat and what you eat, learn how to change the time and dose of your rapid-acting insulin to match this. 

  • Ask your healthcare provider if it is safe for you to drink alcohol. Never drink on an empty stomach.

  • Take your medicine at the prescribed times.

  • Always carry a source of fast-acting sugar and a snack when you’re away from home.

Other things to do

Additional tips include the following:

  • Carry a medical ID card, a compact USB drive, or wear a medical alert bracelet or necklace. It should say that you have diabetes. It should also say what to do if you pass out or have a seizure.

  • Make sure your family, friends, and coworkers know the signs of low blood sugar. Tell them what to do if your blood sugar falls very low and you can’t treat yourself.

  • Keep a glucagon emergency kit handy. Be sure your family, friends, and coworkers know how and when to use it. Check it regularly and replace the glucagon before it expires.

  • Talk with your health care team about other things you can do to prevent low blood sugar.


If you have unexplained hypoglycemia or hypoglycemia several times, call your healthcare provider.