To fix low blood sugar, eat or drink 15 grams of fast-acting carbohydrates immediately, then wait 15 minutes and recheck your level. Blood sugar below 70 mg/dL (3.9 mmol/L) is considered low and needs treatment. A reading below 54 mg/dL (3.0 mmol/L) requires immediate action.
Most low blood sugar episodes resolve quickly when you follow a simple, structured approach. The key is acting fast, using the right type of carbohydrate, and resisting the urge to overeat your way out of it.
The 15-15 Rule
The standard method for treating low blood sugar is called the 15-15 rule, recommended by the CDC: 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 repeating until your blood sugar returns to your target range.
The waiting period matters. It takes roughly 15 minutes for sugar to enter your bloodstream and raise your glucose level. If you skip the wait and keep eating because you still feel shaky, you’ll likely overcorrect and end up with a blood sugar spike. This cycle of lows followed by highs is one of the most common problems people run into when managing blood sugar.
Best Foods for a Quick Fix
Not all carbohydrates work the same speed. You want simple sugars that hit your bloodstream fast, not complex carbs like whole wheat bread or oatmeal. Here are portions that each deliver about 15 grams of fast-acting carbohydrate:
- Glucose or dextrose tablets: 4 to 5 tablets (the preferred option because the dosing is precise)
- Fruit juice or regular soda: 2/3 cup (about 150 mL). It must be regular, not diet.
- Honey: 1 tablespoon
Glucose tablets are the most reliable choice because they’re pre-measured and portable. Juice and soda work well but are easy to over-pour when you’re feeling panicky. Candy bars, chocolate, and ice cream are poor choices. Their fat content slows digestion, which delays the sugar from reaching your blood when you need it most.
What to Eat After Your Level Stabilizes
Once your blood sugar is back above 70 mg/dL, you’re not quite done. If your next meal is more than an hour away, eat a small snack that combines protein and complex carbohydrates. A handful of crackers with peanut butter, a piece of cheese with a few crackers, or half a sandwich all work. This follow-up snack provides slower-burning fuel that keeps your blood sugar from dropping again before your next meal.
When It Becomes an Emergency
Most low blood sugar episodes are mild and self-treatable. But severe hypoglycemia is a medical emergency. The signs include confusion or disorientation, inability to eat or drink, loss of consciousness, and seizures.
If someone cannot swallow food or drink safely, do not try to put anything in their mouth. This is where glucagon comes in. Glucagon is a prescription hormone that rapidly raises blood sugar, and it’s available as an injection kit or nasal spray. If the person is unconscious or seizing, administer glucagon (if available) and call emergency services. Anyone on insulin or medications that can cause severe lows should have a glucagon kit accessible, and the people around them should know where it is and how to use it.
After receiving glucagon, most people regain consciousness within 10 to 15 minutes. Once alert, they should eat a snack to prevent another drop.
Common Causes of Low Blood Sugar
For people with diabetes, the most frequent triggers are taking too much insulin, delaying or skipping a meal after taking medication, or exercising more than usual without adjusting food intake or medication. Alcohol also lowers blood sugar, especially on an empty stomach, because it interferes with the liver’s ability to release stored glucose.
People without diabetes can experience low blood sugar too. Reactive hypoglycemia causes blood sugar to drop a few hours after eating, particularly after high-carbohydrate meals. Other causes include liver, kidney, or pancreatic disease, certain medications, previous stomach surgery, and heavy alcohol use. If you’re experiencing repeated episodes without a clear explanation, tracking when they happen (fasting vs. after meals) gives your doctor useful information for pinpointing the cause.
Preventing Future Episodes
Treating a low is straightforward. Preventing the next one takes more planning. Eating meals and snacks at regular intervals is the single most effective strategy, especially if you take insulin or other blood sugar-lowering medication. Pairing carbohydrates with protein or fat at meals slows digestion and produces a more gradual rise and fall in blood sugar, reducing the chance of a post-meal crash.
If you exercise regularly, check your blood sugar before and after workouts. Physical activity increases how efficiently your muscles use glucose, which means levels can drop during or even hours after exercise. Having a carbohydrate snack before intense activity, or reducing your insulin dose with your doctor’s guidance, can prevent exercise-related lows.
Continuous glucose monitors (CGMs) can be especially helpful for people who experience frequent or unpredictable drops. These devices track blood sugar in real time and can sound an alarm when levels are falling, sometimes before you even feel symptoms. Predictive alerts give you a window to eat something and head off a low before it happens.
Keeping fast-acting glucose within reach at all times is a simple habit that makes a real difference. Stash glucose tablets in your car, your desk, your nightstand, and your gym bag. The worst time to look for treatment is when your blood sugar is already low and your thinking is foggy.