When your blood sugar drops below 70 mg/dL, you need fast-acting sugar immediately. The standard approach is called the 15-15 rule: eat 15 grams of simple carbohydrates, wait 15 minutes, then recheck your blood sugar. If it’s still under 70 mg/dL, repeat. Most mild episodes resolve within one or two rounds of this process.
How to Recognize Low Blood Sugar
Your body sends out warning signals in a predictable order. The earliest symptoms come from your nervous system reacting to the drop: sweating, shaking, a pounding heartbeat, sudden anxiety, and intense hunger. These are your built-in alarm system, and they typically appear while you still have time to treat yourself.
If blood sugar keeps falling, the symptoms shift from physical to mental. You may notice confusion, difficulty concentrating, irritability, or trouble speaking clearly. At this stage, thinking and decision-making become harder, which is exactly why it’s important to act on the earlier warning signs. Below 54 mg/dL is considered severe, and at that point seizures, loss of consciousness, and inability to swallow become real risks.
The 15-15 Rule Step by Step
The moment you feel symptoms or your meter confirms a reading under 70 mg/dL, eat or drink 15 grams of fast-acting carbohydrates. Good options that deliver roughly 15 grams:
- 3 glucose tablets
- Half a cup (4 ounces) of fruit juice or regular soda
- 6 or 7 hard candies
- 1 tablespoon of sugar (dissolved in water if needed)
Set a timer for 15 minutes, then test again. If you’re still below 70 mg/dL, have another 15 grams and wait another 15 minutes. Keep repeating until your blood sugar is back in your target range.
For young children, especially infants and toddlers, 15 grams can be too much. Their dose is typically smaller and should be determined by their pediatrician.
Why Chocolate and Peanut Butter Don’t Work
This is one of the most common mistakes. Reaching for chocolate, peanut butter, nuts, or any high-fat food during a low feels intuitive, but fat slows your body’s absorption of carbohydrates. Your blood sugar won’t rise fast enough when every minute counts. Save those foods for later. During the acute drop, you want pure, simple sugar with as little fat as possible.
What to Eat After Your Blood Sugar Recovers
Once your reading is back above 70 mg/dL, you’re not done. Simple sugar burns off quickly, and without a follow-up snack or meal, your blood sugar can drop right back down. Eat something that pairs carbohydrates with protein: peanut butter on crackers, cheese and crackers, eggs and toast, or a handful of trail mix. The protein helps stabilize your blood sugar over the next few hours and prevents a second dip.
What to Do for Severe Lows
If someone with low blood sugar has passed out, is having a seizure, or can’t swallow, do not try to put food or liquid in their mouth. They could choke. This is where glucagon comes in.
Glucagon is a prescription emergency medication that rapidly raises blood sugar. It comes in three forms: a nasal spray, a pre-mixed auto-injector pen (similar to an EpiPen), and a traditional kit that requires mixing powder with liquid before injecting. The nasal spray is the simplest for bystanders to use, since it’s a single step with no needles involved. You insert the tip into one nostril and press the plunger.
If you’re using an injectable pen, remove the cap, insert the needle straight down into the outer thigh, upper arm, or lower stomach, and press the plunger. With any form of glucagon, roll the person onto their side afterward, because vomiting is a common side effect and you need to protect their airway.
Call 911 if the person doesn’t regain consciousness, if you don’t have glucagon available, or if you’re unsure how to administer it.
Lows That Happen During Sleep
Nighttime low blood sugar is particularly dangerous because you’re not awake to notice the early warning signs. A bed partner might notice restless sleep, sweating, shaking, sudden changes in breathing, or a racing heartbeat. Nightmares that jolt you awake can also be a sign.
If nighttime lows happen more than occasionally, a few strategies can help. A continuous glucose monitor with a low-threshold alarm can wake you before your blood sugar drops to a dangerous level. Some people set an alarm for the early morning hours to check their levels and track how often episodes occur. Adjusting the timing or dose of evening insulin, with guidance from a healthcare provider, is often the most effective long-term fix. Keeping a glucagon kit in your bedside drawer ensures fast access if a severe episode happens while you’re asleep.
Preparing Before It Happens
Low blood sugar episodes are far less scary when you’ve planned for them. Keep glucose tablets or a small juice box in your bag, your car, your desk, and your nightstand. If you take insulin or medications that can cause lows, ask your doctor about a glucagon prescription and make sure the people you live or work with know where it is and how to use it.
Wearing a medical ID bracelet matters more than most people realize. If you lose consciousness in public, first responders need to know you have diabetes before they can treat you effectively. A bracelet or medical ID on your phone’s lock screen gives them that information in seconds.