To reverse low blood sugar, eat 15 grams of fast-acting carbohydrates, wait 15 minutes, and recheck your blood sugar. If it’s still below 70 mg/dL, repeat. This approach, known as the 15-15 rule, is the standard first-line treatment recommended by the CDC and works for most mild to moderate episodes. But there’s more to a full recovery than that initial sugar hit, and how you handle the minutes and hours after matters just as much.
The 15-15 Rule Step by Step
The logic is simple: give your body a precise dose of sugar, then give it time to absorb. Eating 15 grams of fast-acting carbohydrates raises your blood sugar without overshooting into high territory. After 15 minutes, check again. If you’re still under 70 mg/dL, eat another 15 grams and wait another 15 minutes. Keep repeating until your blood sugar returns to your target range.
Good sources of 15 grams of fast-acting carbs include:
- 4 glucose tablets
- 4 ounces (half a cup) of fruit juice
- A tablespoon of honey or sugar
- A small handful of regular (non-diet) candy like jelly beans
- 4 ounces of regular soda
The key word is “fast-acting.” You want simple sugars that hit your bloodstream quickly. Chocolate, cookies, or ice cream contain fat that slows digestion, making them poor choices when you need your levels up now. Stick with pure sugar sources for the initial treatment.
What Your Body Does Behind the Scenes
While you’re eating those glucose tablets, your body is already running its own rescue operation. When blood sugar drops below about 60 to 65 mg/dL, your system releases a cascade of hormones designed to push glucose back into your bloodstream. Glucagon, the most important of these, signals your liver to dump its stored glucose. Adrenaline kicks in next, which is why low blood sugar often comes with shakiness, a racing heart, and sweating. Cortisol and growth hormone join in to further oppose insulin’s effects and keep glucose levels from falling further.
This hormonal surge is the reason you feel so awful during a low. The shakiness, anxiety, and rapid heartbeat aren’t just symptoms of low sugar itself. They’re side effects of your body flooding itself with stress hormones to survive the drop. Understanding this helps explain why you may still feel terrible for a while even after your numbers come back up.
Follow Up With a Lasting Snack
Once your blood sugar is back above 70 mg/dL (or 4 mmol/L), the job isn’t finished. Fast-acting carbs burn through quickly, and without a follow-up, your blood sugar can drop right back down. If your next meal is more than two hours away, eat a snack that contains 15 to 20 grams of slow-release carbohydrates paired with some protein or fat. This combination digests more gradually and holds your levels steady.
Good follow-up snacks include:
- A slice of whole-grain bread with peanut butter
- Crackers with cheese
- A small portion of fruit with yogurt
- A quarter cup of hummus with half a pita
If a meal is coming soon, just eat the meal. The point is to avoid leaving a gap where your blood sugar has nothing sustaining it.
Handling Severe Lows
Sometimes a low is too severe to treat with food. If someone is confused, unable to swallow safely, or unconscious, they need glucagon, a hormone that forces the liver to release its glucose stores into the bloodstream. Glucagon comes in three forms: a nasal spray that works like a single puff into one nostril, a pre-mixed injectable pen similar to an EpiPen, and a traditional kit where a caregiver mixes powder with liquid before injecting. The nasal spray is the easiest for bystanders to use because it requires no needles and no mixing.
If someone is unconscious after receiving glucagon, roll them onto their side to prevent choking if they vomit. Anyone who loses consciousness from low blood sugar needs emergency medical attention, even if glucagon brings them around. If you take insulin or medications that can cause lows, make sure people close to you know where your glucagon is stored and how to use it.
Preventing Lows During Sleep
Nighttime lows are particularly dangerous because you can’t feel the warning signs while asleep. Research shows that a bedtime snack combining carbohydrates, protein, and fat works best at preventing overnight drops, especially when your blood sugar is below 130 mg/dL at bedtime. Aim for 15 to 30 grams of carbohydrates paired with a protein source.
Practical options include a bowl of cereal with milk, crackers with nut butter, cottage cheese with half a banana, or a small sandwich with lean protein. The fat and protein slow the digestion of the carbohydrates, creating a steady trickle of glucose through the night rather than a spike and crash.
Untreated overnight lows can also trigger what’s called rebound hyperglycemia, sometimes known as the Somogyi effect. Your body detects the low while you sleep, dumps adrenaline, cortisol, and growth hormone, and you wake up with blood sugar that’s confusingly high. If you’re seeing unexplained high morning readings, an undetected overnight low may be the cause. A continuous glucose monitor or checking your blood sugar at 2 or 3 a.m. for a few nights can help identify the pattern.
Why Some People Stop Feeling Lows
Repeated episodes of low blood sugar can dull your body’s ability to recognize them. This condition, called hypoglycemia unawareness, means you lose the early warning signs like shakiness and sweating, and your blood sugar can plummet into dangerous territory before you notice anything is wrong. Some people don’t feel symptoms until they’re already in the 50s, at which point confusion and impaired judgment make it harder to treat yourself.
The main danger is losing consciousness without warning, which can lead to car accidents, falls, or injuries at work. Recurrent severe lows also carry longer-term risks: people who experience an episode of severe hypoglycemia have a higher chance of heart attack or stroke in the following year. The good news is that hypoglycemia unawareness is often reversible. Carefully avoiding lows for several weeks can restore your body’s ability to detect them. This typically requires working with your care team to adjust medication doses and blood sugar targets temporarily.
Common Mistakes When Treating a Low
The most frequent error is overtreating. When your blood sugar is crashing and you feel shaky and panicked, it’s natural to eat everything in sight. But eating 60 grams of sugar instead of 15 sends your blood sugar rocketing upward, leading to a high that you then need to correct, which can trigger another low. The 15-15 rule exists specifically to prevent this cycle. Measure your carbs, set a timer, and resist the urge to keep eating during those 15 minutes.
Another common mistake is treating with foods that are too slow. A peanut butter sandwich is great as a follow-up snack, but it won’t raise your blood sugar fast enough in the acute moment. Use pure sugar first, then switch to complex foods once your levels are stable. Finally, don’t skip the recheck. Feeling better doesn’t always mean your numbers are actually back in range, and assuming you’re fine without confirming can leave you vulnerable to a second drop.