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Understanding hypoglycaemia

Sometimes, drops in glucose can sneak up on you—even overnight1. Low glucose happens, but with your FreeStyle Libre 2 or FreeStyle Libre 3 system, you don’t have to guess what’s happening.

Woman in a navy tennis dress sitting on a bench beside a court, checking her phone. A FreeStyle Libre 2 Plus glucose sensor is visible on her upper arm. Woman in a navy tennis dress sitting on a bench beside a court, checking her phone. A FreeStyle Libre 2 Plus glucose sensor is visible on her upper arm. Woman in a navy tennis dress sitting on a bench beside a court, checking her phone. A FreeStyle Libre 2 Plus glucose sensor is visible on her upper arm.

What is hypoglycaemia?

A “low,” also called hypoglycemia, happens when your glucose levels drop below your target range, usually below 3.9 mmol/L2. At that point, your body doesn’t have enough glucose for energy.

If your levels dip below 3.0 mmol/L, it can become dangerous2. Everyone’s body reacts differently, so speak to your healthcare professional for questions about your healthy range3.

When a low is happening, you might experience a sudden wave of shakiness, a feeling that something’s off4, or wake up to a low glucose alarm from your phone.◊

Man in athletic wear sat outdoors, looking at his mobile phone. A FreeStyle Libre 2 Plus sensor is visible on his upper arm Man in athletic wear sat outdoors, looking at his mobile phone. A FreeStyle Libre 2 Plus sensor is visible on his upper arm Man in athletic wear sat outdoors, looking at his mobile phone. A FreeStyle Libre 2 Plus sensor is visible on his upper arm

What causes hypoglycaemia?

Lows are common for people with diabetes1, but learning what causes them helps you stay ahead.


Causes of lows.

  • Skipping or delaying meals5

  • Eating less than usual1

  • Physical activity or more intense activity than usual6,7

 

What is nocturnal hypoglycaemia?

Hypos don't just happen during the day. Your glucose may also drop at night, but your LibreLink app or Libre 3 app alarms^ will let you know when levels dip, even when you’re asleep.

This is called nocturnal hypoglycaemia8 and can happen for a few reasons.


Causes of nighttime dips8.

  • Skipped meals

  • Exercise before bedtime

  • Alcohol before bedtime

  • Infections

 

What are the symptoms of hypoglycaemia?

If your glucose is dropping, you might feel these early signs4.

  • Sweating, chills, or clamminess

  • Irritability or confusion

  • Hunger or nausea

  • Feeling sleepy, weak, or losing energy

  • Tingling or numbness in the lips, tongue, or cheeks

  • Shakiness or dizziness

Not everyone feels their lows the same way. Over time, you’ll learn how your own body signals a dip, and your FreeStyle Libre 2 system or FreeStyle Libre 3 system helps you see those changes, even when you don’t feel them right away.

How to prevent lows.

Know what lows feel like so you can treat them sooner

Check levels often to lower your risk of hypoglycaemia1

Look at patterns and trends to know how meals and activity impact levels

Eat meals regularly5

Low glucose alarm notification Low glucose alarm notification

Low alarms help you act.

If your glucose drops unexpectedly, the FreeStyle Libre 2 system or FreeStyle Libre 3 system optional alarms^ will notify you the moment it happens.

An alarm will appear on your phone’s screen, displaying your current reading and a trend arrow indicating where your glucose is headed.

 

Optional glucose alarms Optional glucose alarms

Set your optional alarms^.

You can personalise your alarms so you’re alarmed when you want to be—and when you don’t. You can choose the threshold numbers for when LibreLink app or Libre 3 app alarms you of a dip, and you can silence them if needed.

Further reading

Trend Arrows

⏱ 2 minutes read

Trend arrows allow you to see the direction your glucose is heading, allowing you to take corrective measures in advance.

Read article here

Triangle of Diabetes Care

⏱ 5 minutes read

Stay in control by tracking the three pillars of diabetes care with the FreeStyle Libre systems.*

Read article here

References & Disclaimers

Images are for illustrative purposes only. Not real patients or data.

1. American Diabetes Association. “Causes and How to Prevent Hypoglycemia (Low Blood Glucose).” American Diabetes Association. https://diabetes.org/living-with-diabetes/hypoglycemia-low-blood-glucose/causes-prevention. (Last accessed: April 2026)

2. American Diabetes Association Professional Practice Committee. "6. Glycemic Goals and Hypoglycemia: Standards of Care in Diabetes—2026." Diabetes Care 49, no. Supplement_1 (January 2026): S132-S149. 
https://diabetesjournals.org/care/article/49/Supplement_1/S132/163927/6-Glycemic-Goals-Hypoglycemia-and-Hyperglycemic (Last accessed: April 2026)

3. Battelino, T. “Clinical Targets for Continuous Glucose Monitoring Data Interpretation: Recommendations From the International Consensus on Time in Range.” Diabetes Care (2019) 42(8):1593–1603: https://doi.org/10.2337/dci19-0028.

4. American Diabetes Association. “Signs, Symptoms, and Treatment for Hypoglycemia (Low Blood Glucose).” American Diabetes Association. Accessed February 4, 2026. https://diabetes.org/living-with-diabetes/hypoglycemia-low-blood-glucose/symptoms-treatment.

5. ​​Johns Hopkins Medicine. “Hypoglycemia (Low Blood Sugar).” Johns Hopkins Medicine. https://www.hopkinsmedicine.org/health/conditions-and-diseases/diabetes/hypoglycemia-low-blood-sugar. (Last accessed: April 2026)

6. Nakhleh, A., and N. Shehadeh. “Hypoglycemia in Diabetes: An Update on Pathophysiology, Treatment, and Prevention.” World Journal of Diabetes 12, no. 12 (December 15, 2021): 2036–49. https://doi.org/10.4239/wjd.v12.i12.2036

7. American Diabetes Association. “Blood Glucose and Exercise.” American Diabetes Association. https://diabetes.org/health-wellness/fitness/blood-glucose-and-exercise. (Last accessed: April 2026)

8. Johns Hopkins Medicine. “Hypoglycemia: Nocturnal.” Johns Hopkins Medicine.
https://www.hopkinsmedicine.org/health/conditions-and-diseases/diabetes/hypoglycemia-nocturnal. (Last accessed: April 2026)

◊ The FreeStyle Libre systems apps are only compatible with certain mobile devices and operating systems. Please check our website for more information about device compatibility before using the apps. Use of the FreeStyle Libre systems apps may require registration with LibreView

^ Notifications will only be received when alarm settings are enabled and turned on and sensor is within 6 metres (20 feet) for FreeStyle Libre 2 system or 10 metres (33 feet) for FreeStyle Libre 3 system of the reading device, unobstructed.

ADC-2689923 v1.0
 

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