Quick answer: Missing a dose of insulin can lead to symptoms like high blood sugar, fatigue, and in some cases, diabetic ketoacidosis (DKA). Recognizing missed insulin dose symptoms early and knowing what to do next can help you stay safe and get back on track quickly.
Insulin therapy is a life-saving treatment for people with both type 1 and type 2 diabetes. But it comes with its own set of challenges, like missing a dose.
Forgetting an insulin injection happens to every diabetic at some point, and more often than you'd think.
Diabetes management requires constant attention, precise calculations, and strict injection schedules. But we're all human. It's easy to lose track, get distracted by a busy day, or simply oversleep.
In this blog, we'll explain exactly what happens when you miss a dose of insulin, the symptoms to watch out for, and how to handle different missed doses, whether long-acting, fast-acting, or evening insulin.
We'll also share practical strategies to help you stay on track and know when to seek medical help.
Related article: What to Do If You Run Out of Insulin?
What happens if you forget to take your insulin?
Forgetting to take insulin can affect your body differently depending on the type of insulin you missed.
- Long-acting insulin: Missing a dose of long-acting insulin can lead to gradually rising blood sugar levels throughout the day or night. You might not notice symptoms immediately, but high blood sugar can cause fatigue, thirst, and frequent urination over time.
- Fast-acting (mealtime) insulin: If you forget your insulin before eating, your blood sugar can spike quickly after a meal. This can cause symptoms to appear more rapidly, especially if your meal was high in carbs or sugar.
Signs of high blood sugar after a missed insulin dose
One of the main risks of missing insulin is hyperglycemia (high blood sugar). If not treated, it can lead to diabetic ketoacidosis (DKA), a serious condition that happens when your body starts breaking down fat for energy because it doesn't have enough insulin.
Watch for signs of DKA, especially if you missed a dose of insulin and have type 1 diabetes:
- 🚨Fruity-smelling breath
- 🚨Rapid breathing
- 🚨 Nausea or vomiting
- 🚨 Fatigue or confusion
- 🚨 Abdominal pain
- 🚨 Very high blood sugar levels
DKA is a medical emergency. If you think you may be experiencing it, seek medical help immediately.
Related article: How to Store Insulin Without Refrigeration? Practical Tips from a Type 1 Diabetic!
Is it OK to skip an insulin injection?
It's never recommended to skip your insulin dose intentionally. Even missing just one dose can cause blood sugar to rise, especially if you're eating meals or snacks as usual.
Consistently skipping insulin doses can lead to serious complications like DKA or long-term organ damage. If you're having trouble sticking to your routine, talk to your healthcare provider about ways to adjust your insulin plan.
What happens if you miss a dose of long-acting insulin?
Long-acting insulin (also called basal insulin) helps keep your blood sugar steady over time, especially when you're not eating, like in between meals and during the night. If you miss a dose of long-acting insulin:
- Your blood sugar may rise slowly but steadily
- You may feel tired, thirsty, or need to urinate more often
- You may need to adjust your next dose or take a partial catch-up dose, but only if your doctor recommends it.
Do not double your next dose of basal insulin without guidance. Call your doctor for advice on how to handle a missed long-acting insulin injection safely.
What to do if you forgot to take your long-acting insulin
Missing a dose of long-acting insulin, like Lantus, Basaglar, or Levemir, requires some specific actions. First, don't panic! It's a common issue; the key is acting as soon as possible. Here's what you should do:
1. Stay calm and assess: If you've missed your long-acting insulin, don't stress. Stress can worsen your blood sugar levels. Keep calm, and remember that with the right action, you can stay on track.
2. Should you take a dose?
✅ If you missed your dose within 2 hours of your usual schedule, taking your regular dose is generally okay. However, be aware that the effects of the insulin may overlap with your next dose, potentially increasing the risk of low blood sugar.
❌ If more than 2 hours have passed, it's best to call your doctor before taking a dose, as taking too much insulin can increase the risk of severe hypoglycemia.
3. Monitoring is key:
You'll need to monitor your blood sugar closely over the next 24 hours. Missing a dose can cause high blood sugar, or if you take the dose too late, it will overlap with your next dose, causing low blood sugar (hypoglycemia).
Test for ketones if your blood glucose level exceeds 200 mg/dL (11 mmol/L), as missed doses can lead to diabetic ketoacidosis (DKA).
Related article: Does Insulin Really Need to be Refrigerated? Essential Storage Tips!
What if I forgot to take insulin before a meal (fast-acting insulin)?
Fast-acting insulin (also called bolus insulin) is meant to cover the spike in blood sugar after eating. Missing it can cause a sharp rise in glucose levels.
Short-term solutions for missed insulin doses before mealtime
If you remember shortly after eating, you may still be able to take your dose. General tips:
✅ If it's been less than 1-2 hours since you ate, check your blood sugar and take a correction dose if your doctor has shown you how.
❌ If it's been longer, wait until your next mealtime dose. Taking fast-acting insulin too late may cause low blood sugar. Always follow your healthcare provider's specific instructions for your insulin plan.
How to avoid missing bolus insulin at mealtime
✅ Set phone alarms or reminders
✅ Keep your insulin injection kit with you when eating out
✅ Use apps or smart devices that track insulin usage
✅ Prep meals and insulin together so you remember both
Related article: The Ultimate Guide to Traveling with Diabetes: Essential Tips for Packing, Flying, and Managing Your Health on the Go!
What if I forgot to take my evening insulin?
Evening doses often include long-acting insulin, but some people also take mixed or short-acting types of insulin at night.
If you realize you forgot your insulin before bed, don't panic:
- Check your blood sugar
- Call your healthcare provider or follow their previous instructions for missed doses
- Never double the next dose without medical guidance
Signs of low blood sugar while sleeping
Some people accidentally take their evening insulin too late or take too much. Watch for these signs of nighttime hypoglycemia:
- Sweating or chills
- Nightmares or restless sleep
- Waking up with a headache or feeling shaky
- Confusion or trouble waking up
If this happens, eat a quick sugar source (like juice or glucose tablets), then follow up with your doctor.
Related article: How Long Can a Diabetic Go Without Insulin?
Type 2 Diabetes Missed Insulin Dose: What Should You Do?
For people with type 2 diabetes, missing insulin can still cause high blood sugar, though the effects may be less severe than in type 1 diabetes.
Steps to take:
- Check your blood sugar
- Take your missed dose only if your provider has told you how to handle it
- Don't make big changes without guidance-call your doctor to ask if you need a correction dose or should wait until the next scheduled injection.
How to Prevent Missed Insulin Doses
Missing a dose of insulin can be stressful. But the good news is, there are simple ways to prevent it. Building a solid routine and using reminders can make a big difference in keeping your diabetes under control.
Here are a few simple strategies to stay on track of your insulin injection schedule:
✅ Use a daily pill box or insulin organizer
✅ Log your doses in an app or notebook
✅ Link your insulin routine with another habit (e.g., brushing teeth)
✅ Ask a family member or caregiver to remind you
When to Seek Medical Help After Missing an Insulin Dose
Call your doctor or go to the ER if:
⚠️Your blood sugar stays very high, even after taking insulin.
⚠️ You have signs of DKA.
⚠️ You're vomiting, confused, or have trouble breathing
⚠️ You're unsure how to adjust your next dose
Managing Missed Insulin Dose Symptoms: Staying on Track and Healthy
Everyone misses a dose now and then. What matters most is how you respond. By recognizing the symptoms early, understanding the type of insulin you missed, and knowing the right steps to take, you can avoid complications and stay in control of your health. With a few small habits, you can also reduce the chances of missing a dose in the future.
Key Takeaways:
💉 Missed a Dose? Don't Panic: If you've missed a long-acting or fast-acting insulin dose, act fast. Check your blood sugar, assess the timing, and follow the correct steps to stay safe.
⚠️ Know the Missed Insulin Dose Symptoms: Look out for high blood sugar signs like extreme thirst, fatigue, or fruity-smelling breath. These may indicate DKA, especially after skipped injections.
⏰ Forgot Mealtime Insulin? Here's What to Do: If you forgot to take insulin before a meal, you may still have time to correct it. Short-term solutions and guidance from your doctor can help stabilize blood sugar.
💊 Don't Skip Long-Acting Insulin: Missing a dose of long-acting insulin can cause blood sugar spikes over time. Be sure to catch up on your dose as soon as possible to avoid long-term complications.
📲 Prevent Missed Injections: Use smartphone reminders, visual cues, and a consistent routine to avoid missing your insulin. Staying on schedule is key to healthy diabetes management.
We'd Love to Hear From You!
💬 Have you ever missed a dose of insulin? What did you do, and how did you feel?Share your experience, tips to stay on track, or any questions you still have. Your story might help someone else in the same boat!
📆 Article Update History:
✅ Updated: April 17, 2025
Originally Published: August 1, 2022
Comments
4AllFamily Customer Care Team said:
Hi David,
Thanks for your remark. The answer would vary greatly depending on each individual. As a rule of thumbs, if you’ve missed a dose of long-acting insulin and won’t have it until the next day, the best would be to limit carbohydrate intakes. But again, it depends on the individual and that’s something that should be discussed with your diabetes management team.
Best regards,
David Gay said:
It doesn’t say what to do about type of food to eat and how much if you have missed your on long acting insulin dose at better and have forgotten until its too late