If your blood sugar is below 70 mg/dL (3.9 mmol/L), eat or drink 15 grams of fast-acting carbohydrates immediately. This is the single most important step, and it works within minutes. A blood sugar below 54 mg/dL (3.0 mmol/L) is more dangerous and requires immediate action, potentially including emergency help if the person can’t swallow or loses consciousness.
The 15-15 Rule
The standard approach to treating low blood sugar is simple: eat 15 grams of fast-acting carbohydrates, wait 15 minutes, then check your blood sugar again. If it’s still below 70 mg/dL, repeat the process. Keep going until your blood sugar is back in your target range.
The key word here is “fast-acting.” You want sugar that hits your bloodstream quickly, not something with fat or fiber that slows digestion. Good options that provide roughly 15 grams of carbohydrates include:
- 4 ounces (half a cup) of fruit juice
- 4 ounces of regular soda (not diet)
- 1 tablespoon of honey or sugar
- 3 to 4 glucose tablets
- 1 small bunch of about 17 grapes
- Half a banana
- 15 to 20 pretzels
Resist the urge to eat everything in sight. Overtreating a low can send your blood sugar soaring in the other direction. Stick to 15 grams, wait the full 15 minutes even though it feels like an eternity, and retest.
What to Eat After Your Blood Sugar Recovers
Once your blood sugar is back above 70 mg/dL, eat a small meal or snack that includes both protein and complex carbohydrates. A meat sandwich, crackers with cheese, or peanut butter on toast all work well. The fast-acting sugar you just consumed will wear off relatively quickly, and without a more substantial follow-up, your blood sugar can drop again. If your next regular meal is more than an hour away, this step is especially important.
How to Recognize Low Blood Sugar
Your body sends clear warning signals when blood sugar starts to fall. Early symptoms include shaking, sweating, a fast heartbeat, sudden hunger, dizziness, and feeling anxious or irritable. These are your body’s stress response kicking in, trying to alert you that something is off.
As blood sugar drops further, the symptoms shift from uncomfortable to dangerous. You may feel weak, have trouble walking or seeing clearly, act confused, or struggle to think straight. At very low levels, seizures and loss of consciousness can occur. If you notice the early warning signs, treat them right away. Waiting to see if you “feel better on your own” only gives your blood sugar more time to fall.
Some people, particularly those who have had diabetes for many years, develop what’s called hypoglycemia unawareness. Their bodies stop producing those early warning symptoms, so their blood sugar can drop to dangerous levels without the usual shaking or sweating. Regular blood sugar monitoring is the only reliable safety net in that situation.
When Someone Else Needs Your Help
If you’re with someone who has severely low blood sugar and they can still swallow safely, help them eat or drink something sugary. But if they’ve lost consciousness or can’t swallow, do not try to put food or liquid in their mouth. They could choke.
This is when glucagon matters. Glucagon is a prescription emergency treatment that raises blood sugar rapidly. It comes in forms that can be injected under the skin or sprayed into the nose, and it works even when the person is unconscious. If the person carries a glucagon kit, use it according to the instructions (ideally, you’ve reviewed these before an emergency). After giving glucagon, call 911. Once the person is alert and able to swallow, have them drink juice or regular soda and then eat something more substantial like a sandwich.
Call 911 immediately if you can’t find the person’s glucagon, don’t know how to use it, or if the person remains unconscious after receiving it.
Common Causes of Low Blood Sugar
Understanding why your blood sugar dropped helps you prevent it from happening again. The most common triggers include:
- Medication timing: Taking insulin or certain diabetes medications without eating enough food afterward, or taking too large a dose.
- Skipping or delaying meals: Your medication keeps working even if you don’t eat on schedule.
- Physical activity: Exercise makes your muscles absorb glucose from your blood more efficiently. An unexpectedly long walk, a harder workout than usual, or activity at an unusual time of day can all cause a drop.
- Alcohol: Your liver normally releases stored glucose to keep your blood sugar steady, but processing alcohol interferes with that job. Drinking on an empty stomach is particularly risky.
If you notice a pattern, like lows that happen every afternoon or after a certain type of exercise, that’s useful information to share with your care team. Adjusting medication doses or timing is often straightforward once the trigger is identified.
Low Blood Sugar While You Sleep
Nocturnal hypoglycemia is especially tricky because you can’t recognize the symptoms while you’re asleep. Signs that suggest it happened overnight include waking up with damp or sweaty sheets, having nightmares, feeling unusually tired or groggy the next morning, or waking with a headache. A partner or roommate might notice restless sleep, trembling, or sudden changes in your breathing pattern.
Preventing nighttime lows often involves adjusting the dose or timing of evening medication, checking blood sugar before bed, and having a small snack if levels are trending low. A continuous glucose monitor can be particularly valuable here, since many models will sound an alarm if your blood sugar drops below a set threshold while you’re sleeping. If nighttime lows are happening regularly, it’s worth discussing with your care team, because the fix is usually a simple medication adjustment.
Staying Prepared
The best time to prepare for low blood sugar is before it happens. Keep fast-acting glucose sources in your bag, your car, your desk, and your nightstand. Glucose tablets are convenient because they don’t melt, spoil, or require refrigeration, and each tablet has a precise carbohydrate count printed on the package.
If you take insulin or a medication that can cause lows, ask about getting a prescription for emergency glucagon. Make sure at least one person you spend time with regularly, whether that’s a partner, coworker, or roommate, knows where you keep it and how to use it. A 30-second walkthrough now can make all the difference in an emergency later. Wearing a medical ID bracelet or keeping medical information on your phone’s lock screen also helps first responders act quickly if you’re unable to communicate.