What is Hypoglycemia or Low Blood Sugar?

Adults and children living with diabetes, especially those treated with insulin, are at risk for experiencing hypoglycemia, or low blood sugar. Hypoglycemia is a state where blood glucose (blood sugar) levels fall below a normal range, usually less than 70 milligrams per deciliter (mg/dL). You may also hear it referred to as insulin shock or insulin reaction. It is important to speak with your healthcare provider to determine individual blood sugar targets.

Common, milder symptoms of hypoglycemia are headaches, shakiness, dizziness, weakness, anxiety and irritability. More severe symptoms can be life-threatening and include confusion, slurred speech, loss of consciousness and seizures. It is important to know the signs and be prepared for lows in order to avoid progressing to the severe symptoms of hypoglycemia. If you are experiencing symptoms of hypoglycemia, you should check your blood sugar level. If you are unable to check your blood sugar, treat yourself as if you have hypoglycemia and test as soon as possible.

Hypoglycemia can happen very quickly and each person’s reaction is different, so it is important to learn to recognize your own signs and symptoms. It is also important to know how to correct it and always be prepared to correct it. If you have a child with diabetes, collaboration with family, school personnel, daycare providers and healthcare providers is imperative for knowing how to recognize and treat hypoglycemia.

Symptoms and Signs of Hypoglycemia

Symptoms of hypoglycemia may be mild, such as loss of energy and shakiness, but if not corrected quickly, blood sugar levels may continue to plummet and lead to more severe symptoms such as seizures and loss of consciousness.

Most people find that they have their unique set of signs and symptoms to alert them to low blood sugar. It is important to become familiar with your signs and symptoms so that you know when to treat hypoglycemia. Keep in mind that your unique symptoms may change over time as well. The list below identifies signs and symptoms of low blood sugar, beginning with mild and progressing to severe symptoms.

Sometimes it may not be possible for a child to communicate that he or she is experiencing symptoms of low blood sugar. If you care for a child with diabetes, take time to learn the signs of hypoglycemia and check the child’s blood sugar levels if you are suspicious.

Signs and symptoms:

  • shakiness
  • sweating
  • impaired/blurred vision
  • dizziness (feeling lightheaded)
  • not thinking clearly
  • feeling nervous or anxious
  • weakness
  • numbness, tingling of mouth and lips
  • feeling tired
  • headaches
  • hunger
  • nausea
  • heart beating fast
  • irritable
  • agitated
  • confusion
  • lack of coordination
  • personality change
  • difficulty speaking
  • fainting/unconsciousness
  • having seizures or convulsions
  • go into a coma

Causes of Low Blood Sugar

Low blood sugar can occur for several reasons, including:

  • Taking too much insulin or diabetes medication.
  • Not eating enough carbohydrate or delaying or skipping a meal.
  • Being more physically active than usual without adjusting medications or eating more.
  • Drinking alcohol, especially on an empty stomach. Alcohol can affect blood sugar levels while you are drinking and for several hours afterward.
  • Attempting to maintain tight blood sugar control.

It is not always easy to identify why your blood sugar went too low. What is important is correcting it right away. Later, take some time to reflect on what may have caused it. This may help lower the chance of low blood sugar from happening often. And do not forget, always be prepared!

Are You at Risk?

Not everyone with diabetes is at the same level of risk for low blood sugar. People with type 1 diabetes and those being treated with insulin or other diabetes medications may have a higher risk of experiencing hypoglycemia.

Research shows...

Type 1 Diabetes Type 2 Diabetes
May experience, on average, 43 symptomatic hypoglycemic episodes annually. Severe hypoglycemic episodes may occur twice annually. If using insulin, may experience an average of 16 symptomatic hypoglycemia episodes annually. Severe hypoglycemic episodes may occur once in five years.

Learn the actions of your medications from your healthcare provider and know your risks for low blood sugar episodes


Perlmuter LC, Flanagan BP, Shah PH, Singh SP. Glycemic control and hypoglycemia: is the loser the winner? Diabetes Care 2008;31:2072-2076.

Mild to Moderate Hypoglycemia

How to Correct a Low Blood Sugar Episode

Step 1: Check Your Blood Sugar — If you feel symptoms of low blood sugar, check your blood sugar. If your blood sugar is below 70 mg/dL or at a level designated by your healthcare provider to be too low, correct it. If you are not able to check your blood sugar, but you feel that it is too low, correct it.

Step 2: Consume 15 to 20 grams* of glucose or simple carbohydrates — Pure glucose is the preferred treatment for low blood sugar. Convenient sources of 15 to 20 grams of pure glucose are glucose tablets, liquids and gels.

If you do not have one of these sources of pure glucose, correct low blood sugar by consuming 15 to 20 grams* of a food or beverage containing carbohydrate such as juice, regular soda, skim milk or hard candy. Avoid consuming snacks that are high in fat because the fat may delay carbohydrate absorption. Also, do not consume too much carbohydrate in order to avoid excess calories and rebound hypoglycemia.

Step 3: Wait 15 minutes and then check your blood sugar again — If your blood sugar has risen to within your target range, it is likely that you can resume your activities. If your blood sugar is still too low, consume another 15 to 20 grams* of pure glucose or simple carbohydrate and check again in 15 minutes.

Step 4: Consider eating a snack if your next meal is one to two hours away — If your next meal is more than an hour away you may need to eat a snack to help keep your blood sugar stable until your next meal.

It is important to talk to your healthcare provider about what is best for you when it comes to correcting low blood sugar. It is best to plan ahead and always be prepared!

*Younger children with Type 1 diabetes may need less glucose. Discuss with a healthcare professional.

Severe Lows

Severe hypoglycemia, or very low blood sugar, is dangerous and potentially life-threatening. Symptoms of severe low blood sugar include seizures and loss of consciousness. These conditions hinder the ability to consume a source of glucose or carbohydrate, so the person must rely upon someone else to help correct the low blood sugar and regain consciousness. Therefore, it is important to inform trusted family, friends and co-workers about hypoglycemia and how they can assist you during a severe low.

If you have a severe low, you will want to have a glucagon kit on hand. This kit provides an injection of glucagon, a hormone normally made in the pancreas that raises blood sugar quickly. You will need a prescription for a glucagon kit, so consult your healthcare provider about whether or not you should have one.

A glucagon kit contains a syringe filled with a liquid, a vial of glucagon powder and step-by-step instructions on how to prepare the injection. Learn how to use the kit. Your healthcare provider or diabetes educator may have a practice kit to show you. Also, consider having a dress rehearsal to teach your family, friends and co-workers how to use the kit. Remember, it is possible that you may not be able to use the kit yourself if you are have severe low blood sugar.

Store your glucagon kit where you can easily get to it and let others know where it is. Remember that glucagon kits have an expiration date. Check your kit on a regular basis to make sure that it has not expired.

Finally, make sure that your trusted family, friends and co-workers know how to contact your healthcare provider and let everyone you spend time with know how to recognize the symptoms of severe low blood sugar. Also, let them know that they might have to seek immediate medical assistance if they are not comfortable using the glucagon kit or they feel you need emergency help.

Hypoglycemia Unawareness

After having diabetes for many years, it is possible to experience what is called hypoglycemia unawareness. This is when you have low blood sugar but do not experience any early signs and symptoms. By the time you are aware that you have low blood sugar, you may be in a state of severe hypoglycemia.

It is suggested that people who have hypoglycemia unawareness check their blood glucose level more frequently so they become more aware of when low blood sugar occurs. Also, your healthcare provider may advise you to make adjustments in your diabetes management plan. If you experience hypoglycemia unawareness or severe hypoglycemia you should discuss this with your healthcare provider.

Hypoglycemia Unawareness Tip: Let others know that they should never try to give you liquid or solid food if you are having a seizure or are unconscious due to low blood sugar because this could cause you to choke. After using a glucagon kit, they should immediately seek medical assistance.

Hypoglycemia Do’s and Don’ts

Low Blood Sugar Do's

  • Be prepared! Keep pure glucose on your person and/or in places where you spend a lot of time. For example: desk drawer, vehicle glove compartment, nightstand, purse, briefcase, travel carry-on bag, backpack, child’s lunch box and locker, teacher’s desk, school nurse’s office and daycare provider’s office.
  • Wear medical identification (ID) that helps make others aware that you have diabetes. A bracelet or necklace is commonly used. Wearing medical ID can save your life – a helpful person or emergency personnel can quickly identify that you have diabetes. Also carry a medical alert card in your wallet where your can write details about your diabetes care.
  • Carry your blood sugar checking supplies. If you have signs and symptoms of low blood sugar, you will be able to check for sure and also know when you have corrected it.
  • Tell trusted family, friends and co-workers ahead of time how they can help if you are experiencing low blood sugar. Familiarize them with the signs and symptoms and what you need to raise your blood sugar to your target range.
  • Consider your need for food if your next meal is more than an hour away. Be aware that there may be greater frequency of hypoglycemia while you sleep, so also consider a snack before bedtime.
  • Always check your blood sugar before driving or operating equipment such as lawnmowers. Make sure your blood sugar is in a safe range. If it is too low, correct it. This helps protect you and those around you.
  • Check your blood sugar before going to sleep. Knowing your blood sugar level before going to sleep, and taking any necessary action, can help prevent low blood sugar.
  • If you have a child with diabetes, inform those around your child about the signs and symptoms of low blood sugar and what they can do to help

Low Blood Sugar Don'ts

  • Do not assume that you will be able to find pure glucose, soda, juice or hard candy at the ready when you are in need of it.
  • Do not ignore mild symptoms of low blood sugar or a blood sugar result that is trending low.
  • Do not be afraid to ask for help, or accept it, if you need it. Sometimes a helping hand can help you overcome a low more quickly.
  • Do not consume too much carbohydrate. This could make your blood sugar levels raise too high, which may cause further complications. Also, eating too much may lead to unwanted weight gain.
  • Try not to panic. Whether you, your child or a person around you is experiencing symptoms of low blood sugar, you want to try to remain calm. If you do feel anxious, try to pause and think clearly about what to do.
Correcting Lows with Glucose

Products formulated with pure glucose are preferred for the treatment of hypoglycemia. It has been demonstrated that glucose tablets raise blood sugar more quickly, without subsequent hyperglycemia, compared to other blood glucose-raising foods. Pure glucose products offer many advantages that make them more convenient for you to always be prepared to correct low blood sugar.

Tablets, liquids and gels specially formulated with glucose:

  • Are fast-acting
  • Are packaged for fast and easy access
  • Come in pre-measured amounts
  • Are convenient to carry and store
  • Do not require refrigeration
  • Contain no fat or caffeine
  • Come in a variety of flavors to suit your taste

Foods for Low Blood Sugar

Fruit juice, milk and hard candies are foods that can help raise low blood sugar. However, the carbohydrate in these foods is both glucose and fructose. Glucose raises blood sugar more quickly than fructose, so pure glucose may help correct low blood sugar faster than a food that contains a mix of glucose and fructose.

While products formulated with pure glucose are preferred for correcting low blood sugar, there are times when you may not have a pure glucose product with you when you need it. The following foods are also good choices to raise your blood sugar level:

  • Fruit juice (4 ounces or ½ cup)
  • Hard candy (see package to determine how many to consume)
  • Regular (non-diet) soda (4 ounces or ½ cup)
  • Nonfat or 1% milk (8 ounces or 1 cup)
  • Raisins (2 tablespoons)

Remember: It is recommended that you check and correct your blood sugar as soon as you begin to feel symptoms of hypoglycemia. If you are unable to check your blood sugar level, correct it as if it is low. Try not to over-correct low blood sugar with too much glucose or food, as this could cause further complications. Consult your healthcare professional to determine what the best course of action is for you.


Brodows RG, Williams C, Amatruda JM. Treatment of insulin reactions in diabetics. JAMA 1984;252:3378-3381.

American Diabetes Association. Glycemic targets. Sec. 6. In Standards of Medical Care in Diabetes—2015. Diabetes Care 2015;38(Suppl. 1):S33–S40