Low Blood Sugar: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Low Blood Sugar?
A primary care doctor usually starts the work-up for low blood sugar. If you have diabetes, an endocrinologist, a doctor who treats hormone and diabetes problems, may help adjust your care. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is low blood sugar?
Low blood sugar is a condition that occurs when the glucose in your blood drops too low. The medical name is hypoglycemia.
For many people with diabetes, low means a reading lower than 70 mg/dL. Your own number might be different, so ask your health care team what level is low for you.
Symptoms
Symptoms tend to come on quickly. They can be different for everyone. They may include:
- Shaking or trembling
- Sweating
- Feeling nervous or anxious
- Feeling irritable or confused
- Dizziness
- Hunger
- Headache
- A fast or pounding heartbeat
- Blurry or double vision
- Tiredness or weakness
Some symptoms, like hunger or sweating, happen when blood sugar is only slightly low. Unclear thinking or a seizure can happen when it is much lower. Very low blood sugar can also cause a person to lose consciousness, which means to pass out. Severe low blood sugar is a medical emergency.
Causes and who gets it
In people with diabetes, insulin and some other diabetes medicines can lower blood sugar too much. Two types of diabetes pills can do this. They are called sulfonylureas and meglitinides. Other causes in people with diabetes include:
- Not eating enough carbohydrates, or skipping or delaying meals
- More physical activity than usual, which can lower sugar for up to 24 hours afterward
- Drinking too much alcohol without enough food
- Being sick and not being able to eat or keep food down
You can still have low blood sugar without diabetes. Causes include severe liver, kidney, or heart failure, hormone deficiencies, and some weight loss surgeries. Certain heart medicines and antibiotics can also cause it. An insulinoma, a rare tumor in the pancreas that makes too much insulin, is another cause.
How doctors diagnose it
If you have diabetes, ask your health care team how to check your blood sugar. The most common way is a blood glucose meter. A continuous glucose monitor, called a CGM, may be a good option. A reading lower than 70 mg/dL on your monitor means low blood sugar.
Treatment
For mild or moderate low blood sugar, eating or drinking something with carbohydrates helps. Carbohydrates are also called carbs. If your sugar is below your target or lower than 70 mg/dL, follow these steps:
- Eat or drink 15 to 20 grams of glucose or carbs right away. Examples are four glucose tablets, one tube of glucose gel, or half a cup of fruit juice that is not low-calorie.
- Wait 15 minutes and check your sugar again.
- Repeat until your sugar is back in your target range.
- If your next meal is more than 1 hour away, have a snack such as crackers or a piece of fruit.
Severe low blood sugar can cause passing out, coma, or even death. Glucagon is a hormone that raises blood sugar, and it is the best way to treat severely low blood sugar. It comes as an injection or a nasal spray. If you have diabetes, your doctor can prescribe a glucagon kit. Teach family, friends, and coworkers how to use it.
When to see a doctor
Call 911 or your local emergency number right away if a person with low blood sugar has a seizure, passes out, cannot be woken up, or becomes less alert. Also call 911 if signs of low blood sugar do not get better after you eat a snack that has sugar. Get a ride to the emergency room. Do not drive yourself.
If a person is unconscious, do not give any food or drink, because they cannot swallow safely. Put the person in the recovery position, which means lying on their side. Give glucagon right away if it is available and you know how to use it. Family, friends, or coworkers should call 911 right away after giving glucagon, or right away if there is no glucagon kit.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. Either can review your medicines and symptoms, order blood tests, and help you make a plan to prevent lows. They can also refer you to a specialist when needed.
Common questions
Can you get low blood sugar without diabetes?
Yes. Causes include severe liver, kidney, or heart failure, hormone deficiencies, some weight loss surgeries, and certain heart medicines and antibiotics. It is important to find the reason your sugar was low, so talk with your provider.
Is low blood sugar dangerous?
It can be. Mild or moderate low blood sugar is easily treated. But severe low blood sugar can cause seizures, brain damage, passing out, coma, or even death. Severe low blood sugar is a medical emergency.
How do you treat low blood sugar?
Eat or drink 15 to 20 grams of glucose or carbs right away, then wait 15 minutes and check your sugar again. Severe lows are treated with glucagon.
Can low blood sugar happen while you sleep?
Yes. Your sugar can drop while you sleep and stay low for several hours. You may not wake up or notice symptoms.
Sources
- MedlinePlus - Low blood sugar
- National Institute of Diabetes and Digestive and Kidney Diseases - Low Blood Glucose (Hypoglycemia)
- National Health Service (NHS) - Low blood sugar (hypoglycaemia)
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
