The fastest way to raise blood sugar is to eat or drink 15 grams of fast-acting carbohydrates, then wait 15 minutes and recheck. This approach, called the 15-15 rule, is the standard method for treating blood sugar that drops below 70 mg/dL. Whether you’re managing diabetes, dealing with reactive hypoglycemia, or helping someone in an emergency, the strategies differ depending on how low blood sugar has fallen and what’s causing it.
Recognizing Low Blood Sugar
Your body sends two waves of warning signals when blood sugar drops. The first wave is driven by your stress response: shakiness, a pounding heart, sweating, sudden hunger, nervousness, and tingling. These symptoms tend to appear when glucose falls below 70 mg/dL and serve as an early alarm.
If blood sugar continues falling below 54 mg/dL, a second set of symptoms emerges because the brain itself is running short on fuel. These include difficulty thinking, confusion, weakness, drowsiness, and feeling unusually warm. At this stage, you need fast-acting sugar immediately. If blood sugar drops low enough to cause loss of consciousness or seizures, that’s a severe episode requiring someone else’s help.
The 15-15 Rule for a Quick Fix
When your blood sugar is low, you want glucose that hits your bloodstream fast, without fiber, fat, or protein slowing it down. Any one of these provides roughly 15 grams of quick carbohydrates:
- 4 ounces (half a cup) of juice or regular soda (not diet)
- 1 tablespoon of sugar, honey, or syrup
- 3 to 4 glucose tablets
- 1 tube of glucose gel
- Hard candies or jellybeans (check the label for the right amount)
After eating one of these, wait 15 minutes and test again. If your blood sugar is still below 70 mg/dL, repeat with another 15 grams. Once your level returns to a safe range, eat a balanced snack or meal containing protein and complex carbohydrates to keep it stable. Skipping that follow-up meal is a common mistake that can send blood sugar right back down.
Why You Shouldn’t Overdo It
When you feel shaky and anxious from a low, the urge to eat everything in sight is powerful. But consuming too much sugar at once can launch blood sugar in the opposite direction. In one study, people with type 2 diabetes who experienced severe lows and received rapid glucose correction rebounded to an average of 195 mg/dL within an hour. These sharp swings aren’t just uncomfortable. Research suggests repeated episodes of severe hypoglycemia can trigger stress hormones and platelet changes that temporarily increase cardiovascular risk. Sticking to 15 grams at a time and rechecking helps you land in a safe range without overcorrecting.
What Happens Inside Your Body
Under normal circumstances, your liver acts as a glucose warehouse. After meals, it stores excess sugar in a compact form called glycogen. When blood sugar dips between meals or overnight, the hormone glucagon signals the liver to break that glycogen back into glucose and release it into the bloodstream. If glycogen stores run low, the liver can also build new glucose from amino acids, fat byproducts, and other raw materials.
This system works automatically in most people. But certain situations can overwhelm it: taking too much insulin, exercising harder than expected, skipping meals, or drinking alcohol on an empty stomach. In these cases, the liver’s reserves can’t keep up, and blood sugar drops faster than the body can compensate.
Emergency Treatment When Someone Can’t Eat
If a person with diabetes loses consciousness or is too confused to safely swallow, never try to put food or liquid in their mouth. This is where glucagon comes in. Glucagon is a hormone that rapidly signals the liver to dump its stored glucose into the bloodstream.
Two forms are available for emergencies. A nasal spray delivers a dose of dry powder into one nostril, requires no injection, and works even if the person is unconscious. A pre-filled pen works similarly to an EpiPen: you remove the cap, press it against the outer thigh, upper arm, or lower abdomen, and it delivers the dose without any mixing or preparation. After giving glucagon, turn an unconscious person on their side to prevent choking if they vomit. If you live with or care for someone at risk of severe lows, keep one of these devices accessible and make sure household members know how to use it.
Raising Blood Sugar Without Diabetes
Not everyone searching for this has diabetes. Reactive hypoglycemia causes blood sugar to drop too low one to four hours after eating, typically after a meal heavy in refined carbohydrates. The body overproduces insulin in response to the sugar spike, then blood sugar crashes. If this pattern sounds familiar, the fix is less about treating individual lows and more about preventing them through how you eat.
Simple carbohydrates like white bread, white rice, pastries, candy, and sweetened drinks break down almost instantly, creating a rapid spike followed by a steep drop. Swapping these for complex carbohydrates creates a slower, more gradual rise that your body can manage without overreacting. Good options include brown or wild rice, quinoa, oatmeal, barley, sweet potatoes with the skin, winter squash, sprouted grain breads, and legumes like beans, lentils, and split peas.
Pairing those carbohydrates with protein and healthy fat slows digestion even further. Eggs, Greek yogurt, cottage cheese, lean meat, fish, nuts, and tofu all work as protein sources. Cook with olive oil or avocado oil, or add nuts and seeds to meals for healthy fats. Load up on non-starchy vegetables like broccoli, Brussels sprouts, cabbage, and cauliflower, which are high in fiber and won’t trigger the spike-crash cycle.
Meal timing matters too. Eating small meals or snacks every two to four hours helps maintain a steady glucose supply. Going long stretches without eating is one of the most common triggers for reactive lows. And if you drink alcohol, always have it with food rather than on an empty stomach, since alcohol impairs the liver’s ability to release stored glucose.
Preventing Overnight Lows
Blood sugar can drop during sleep, which is particularly concerning because you may not wake up to notice symptoms. Research has found that a bedtime snack combining carbohydrates, protein, and fat works best for preventing overnight lows, especially when blood sugar at bedtime is below 130 mg/dL. Aim for 15 to 30 grams of carbohydrates paired with a serving of protein. An apple with peanut butter, crackers with cheese, or a small bowl of cereal with milk all fit this profile. The protein and fat slow carbohydrate absorption, providing a steadier fuel source through the night.
Items to Keep on Hand
If you’re prone to low blood sugar, preparation makes all the difference. Keep glucose tablets or gel in your bag, your car, your desk, and your nightstand. Juice boxes are shelf-stable and pre-portioned. Hard candies travel well but take slightly longer to work since they dissolve slowly. Whatever you choose, the goal is never being more than arm’s reach from a fast-acting sugar source when you need one. For people on insulin or medications that can cause lows, a glucagon device stored where family or coworkers can find it adds an essential layer of safety.