If your blood sugar drops below 70 mg/dL, the fastest way to bring it back up is to eat 15 grams of fast-acting carbohydrates, wait 15 minutes, and recheck. This approach, known as the 15-15 rule, is the standard recommended by the American Diabetes Association and the CDC. Below 54 mg/dL is considered severe and may require help from another person.
Recognizing the Symptoms
Your body sends early warning signals when blood sugar starts dropping. The most common ones are shaking or trembling, sweating, a racing heart, sudden intense hunger, dizziness, and anxiety or irritability. You might also notice tingling in your lips or cheeks, difficulty concentrating, or color draining from your skin. These symptoms can come on quickly, sometimes within minutes.
If blood sugar continues to fall, the brain starts losing its primary fuel source. At that point, symptoms shift to blurred or double vision, slurred speech, poor coordination, disorientation, and in the worst cases, seizures or loss of consciousness. Recognizing the early signs and acting immediately is what prevents things from reaching that stage.
The 15-15 Rule: Step by Step
When you feel symptoms or your meter reads below 70 mg/dL, eat or drink 15 grams of fast-acting carbohydrates right away. Good options include:
- 3 glucose tablets
- Half a cup (4 ounces) of fruit juice or regular soda
- 6 or 7 hard candies
- 1 tablespoon of sugar
Wait 15 minutes, then check your blood sugar again. If it’s still under 70 mg/dL, repeat with another 15 grams. Keep cycling through this process until your reading is back in your target range.
One important detail: avoid reaching for chocolate, peanut butter, ice cream, or other foods high in fat or protein as your first treatment. Fat slows digestion, which delays the glucose from reaching your bloodstream. Save those foods for the next step.
Stabilizing After the Initial Fix
Fast-acting carbs bring your blood sugar up quickly, but they don’t keep it there. Once your reading is back above 70 mg/dL, eat a balanced snack or small meal that combines carbohydrates with protein or fat. Think crackers with cheese, toast with peanut butter, or yogurt with fruit. The protein and fat slow the digestion of the carbs, which helps prevent another drop over the next hour or two.
Skipping this follow-up snack is one of the most common reasons people experience a second low shortly after treating the first one.
What to Do for Severe Lows
When blood sugar drops below 54 mg/dL, or when someone is too confused, uncoordinated, or unconscious to safely eat or drink, they need help from another person. This is where glucagon comes in. Glucagon is a hormone that signals the liver to release stored glucose into the bloodstream, and it’s available as a nasal spray or an injectable kit.
The nasal version is straightforward: you insert the device into one nostril and press the plunger. The person doesn’t need to inhale. It works in children as young as one year old. After administering it, call emergency services. Once the person is alert enough to swallow, offer juice or regular soda followed by a snack like crackers with peanut butter.
If you take insulin, you should have a glucagon prescription on hand at all times. Equally important, the people around you, whether that’s family, coworkers, or school staff, should know where it’s stored and how to use it. Ready-to-use versions that don’t require mixing are now preferred because they’re simpler under pressure.
Common Causes of Low Blood Sugar
The most frequent cause is diabetes medication, particularly insulin. Too high a dose, eating less than usual after taking your regular dose, or exercising more than normal can all tip the balance. Kidney disease compounds this problem because the kidneys can’t clear excess medication as efficiently, allowing blood sugar-lowering drugs to build up in the body.
Low blood sugar also happens in people without diabetes. Reactive hypoglycemia causes blood sugar to drop a few hours after eating, particularly in people who’ve had stomach surgeries like gastric bypass. Heavy drinking without food is another trigger, because alcohol prevents the liver from releasing its glucose reserves. Severe liver disease, serious infections, advanced heart disease, and prolonged fasting can all cause episodes as well.
Preventing Future Episodes
If you’ve had one or more drops below 54 mg/dL, that’s a signal to revisit your treatment plan with your care team. The fix might involve adjusting medication timing, changing doses, or switching to a different drug entirely.
Continuous glucose monitors (CGMs) have changed prevention significantly, especially for people on insulin. These devices track blood sugar in real time and can alert you before you drop into dangerous territory. In a study of insulin-treated drivers with diabetes, low-glucose alerts cut the rate of low blood sugar episodes while driving nearly in half, from 33% to 19%. For those with type 1 diabetes specifically, the time spent in a low range decreased significantly when alerts were active.
Beyond technology, consistent habits make a real difference. Eating regular meals and snacks, checking blood sugar before and after exercise, keeping fast-acting glucose in your car, bag, and nightstand, and not skipping meals after taking medication are all practical steps that reduce your risk. First aid kits at home and work should include glucose tablets or another fast-acting carbohydrate source, so treatment is never out of reach when you need it most.