It happens. You’re distracted by the TV, or you’re exhausted after a long shift, and you suddenly realize you just doubled your basal dose. Or maybe you corrected a high blood sugar reading a little too aggressively. The panic is real. The short answer is yes, you can absolutely take too much insulin, and the medical term for the aftermath is hyperinsulinemia, though most folks just call it a "severe low" or insulin shock.
It’s scary.
Managing diabetes is basically like being a full-time chemist without a degree. You are manually adjusting a hormone that regulates your entire metabolism. If you get the math wrong, the results are immediate. When you have too much insulin circulating in your bloodstream, it forces your cells to soak up glucose (sugar) far too quickly. This leaves your brain—which is a massive energy hog—starving for fuel.
The Biology of an Insulin Overdose
Insulin is the key that opens the doors to your cells. Usually, this is great. It keeps your blood sugar stable. But when you take too much, those doors get ripped off the hinges. Glucose floods out of your blood and into your muscles and fat cells.
Your brain can't store glucose. It needs a constant drip-feed from your blood. When that level drops below about 70 mg/dL, things start getting weird. By the time you hit the 40s or 50s, your central nervous system starts throwing red alerts.
You’ll feel the adrenaline first. This is your body’s "fight or flight" response trying to save you. Your heart races. You sweat—not a normal "I just ran a mile" sweat, but a cold, clammy, "something is wrong" sweat. Your hands might shake so hard you can’t even hold a juice box. This is the body attempting to trigger the release of stored glucose from your liver.
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What Actually Happens During Severe Hypoglycemia
Let’s talk about the symptoms people don’t always mention in the brochures. It isn't just "feeling a bit faint."
- Confusion and "Drunk" Behavior: I’ve talked to people who were pulled over by police because they were driving erratically due to an insulin overdose. They weren't intoxicated; they were hypoglycemic. You might lose your ability to speak clearly or find simple words.
- Visual Disturbances: Some people see spots. Others lose peripheral vision. It's like the world is closing in.
- Emotional Outbursts: Irritability is a huge red flag. If you find yourself suddenly sobbing or screaming at a loved one for no reason after a bolus, check your sugar.
- Seizures and Loss of Consciousness: This is the danger zone. If the brain doesn't get sugar, it eventually shuts down to protect itself.
According to a study published in The Lancet Diabetes & Endocrinology, severe hypoglycemia remains one of the biggest barriers to achieving tight glycemic control. Fear of "going too low" is a psychological weight that many Type 1 and Type 2 diabetics carry every single day.
The Difference Between a Mistake and an Emergency
There’s a scale here. If you took five units too many because you miscounted the carbs in your pasta, you can usually handle that at home with some fast-acting sugar. But if you accidentally injected 50 units of fast-acting insulin instead of your long-acting Lantus or Basaglar, that’s a medical emergency.
Don't wait.
If you realize you’ve made a massive dosing error, you need to start eating fast-acting carbs immediately—think glucose tabs, regular soda (not diet!), or honey. But more importantly, you need to tell someone. If you’re alone, call a friend or emergency services. You might feel fine right now, but insulin has a "peak." Depending on the type, that peak might hit in 30 minutes or 3 hours. You don't want to be unconscious when it does.
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Why Your Body Resists the Fix
Sometimes, you eat the sugar and the numbers don't move. This is "insulin stacking" or just a massive overdose where the insulin is working faster than your stomach can digest food. This is why glucagon is so important.
Glucagon is basically the "anti-insulin." It tells your liver to dump all its stored sugar into the bloodstream at once. In the past, this meant a scary "orange kit" with a giant needle. Nowadays, we have Baqsimi (a nasal powder) and Gvoke (an easy-to-use pen). If you use insulin, you should have one of these. Period.
Chronic Over-Insulinization: The Sneaky Problem
We’ve talked about the "oops" moments, but what about taking a little too much insulin every day? This is actually super common in Type 2 diabetes.
When you have high insulin resistance, your doctor might keep upping your dose. Eventually, you’re on massive amounts of the stuff. This can lead to weight gain, which makes you more insulin resistant, which leads to... more insulin. It’s a vicious cycle. Dr. Jason Fung, a nephrologist and author of The Diabetes Code, often argues that over-prescribing insulin for Type 2 patients can sometimes worsen the underlying cause of the disease (hyperinsulinemia) even while the blood sugar numbers look "good" on paper.
It’s a nuanced debate. Some people need high doses to stay alive and prevent organ damage. Others might find that lifestyle changes can help them lower that dose, reducing the "background noise" of high insulin in the body.
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Real-World Scenarios: How People Mess Up
I’ve seen it all. There’s the "double dose" where you forget you already took your nighttime shot. There’s the "vial mix-up" where the Humalog and the Tresiba bottles look way too similar in the dark. Then there’s the "exercise plummet."
You take your normal dose for lunch. Then you decide to go for a spontaneous 3-mile walk. Muscle activity makes your cells much more sensitive to insulin. Suddenly, that "normal" dose is way too much.
Pro tip: If you use an insulin pump, check your settings. Sometimes a "temp basal" gets left on, or your carb ratio is set incorrectly. Technology is great until it isn't.
Dead-Simple Steps to Manage an Overdose
- Check your blood sugar immediately. Get a baseline.
- The 15/15 Rule: Eat 15 grams of fast carbs (4 oz juice, 1 tbsp honey, 3-4 glucose tabs). Wait 15 minutes. Check again. Repeat until you are above 70 mg/dL.
- Protein and Fat: Once you are stable, eat something with protein and fat (like peanut butter on a cracker). This "anchors" your blood sugar so it doesn't just crash again once the juice wears off.
- Monitor for 4-6 hours. Some insulins have a long tail. Don't assume you're out of the woods just because you feel better 20 minutes later.
- Inform your doctor. They need to know if this is becoming a pattern. Maybe your dosages need a permanent tweak.
Actionable Insights for the Future
Prevention is better than a frantic 2 a.m. bowl of cereal.
- Color-code your pens. Use a rubber band or a piece of colored tape to distinguish your fast-acting insulin from your long-acting one.
- Use a logging app. Or even a physical notebook. If you have to write it down, you won't double-dose.
- Get a CGM. If you don't have a Continuous Glucose Monitor like a Dexcom or Freestyle Libre, look into it. The alarms can literally save your life by alerting you before you hit the danger zone.
- Educate your "Village." Make sure your spouse, roommate, or coworkers know where your glucagon is and how to use it. If you can’t swallow, they shouldn't try to force juice down your throat (choking hazard). They should use the glucagon or call 911.
Taking too much insulin is a rite of passage for many diabetics, as frustrating as that is. It doesn't mean you're failing. It means you're human. The goal is to catch the mistake early, treat it aggressively, and analyze why it happened so you can put a system in place to prevent the next one.
Keep your glucose tabs in the glove box. Keep your glucagon by the bed. Stay safe.
Immediate Next Steps
- Check Your Kit: Verify that your glucagon (Baqsimi, Gvoke, or Zegalogue) is not expired today.
- Review Your Ratios: If you are having lows more than twice a week, schedule a call with your endocrinologist to lower your basal or bolus rates.
- Standardize Your Dosing: Try to take your long-acting insulin at the exact same time and location (e.g., bathroom counter) every day to build a firm habit.