FreeStyle Libre 3 PLUS Sensor

About FreeStyle Libre 3 Plus

The FreeStyle Libre 3 Plus is a small, wearable continuous glucose monitoring (CGM) sensor that measures glucose levels in real time and sends readings directly to your smartphone. It’s designed for people with medically diagnosed diabetes who need regular glucose monitoring.

Unlike traditional finger-prick diabetes testing, which provides a single snapshot reading, FreeStyle Libre 3 Plus continuously measures glucose levels in the interstitial fluid just beneath the skin.

According to the NHS, regular glucose monitoring is essential for people with diabetes to help reduce the risk of complications like heart disease, kidney disease and nerve damage.

Continuous monitoring can improve glucose awareness and reduce episodes of low blood sugar (hypoglycaemia), particularly for people using insulin.

Key features of FreeStyle Libre 3 Plus

• Small and discreet: Approximately the size of a £1 coin and designed to sit. comfortably on the back of the upper arm.
• Real-time readings: Sends glucose data automatically to a compatible smartphone via Bluetooth.
• Optional glucose alarms: Alerts you if your glucose levels are too high or too low.
• 15-day wear time: Each sensor is worn continuously for up to 15 days.
• Factory calibrated: No routine finger-prick calibration required.

The UK regulator, the Medicines and Healthcare products Regulatory Agency (MHRA), oversees the safety of medical devices like CGM systems to ensure they meet appropriate standards.

Who is eligible to use Libre 3 Plus?

FreeStyle Libre 3 Plus is intended for people who:

• are aged four years and over
• have medically recognised type 1, type 2 or gestational diabetes
• require glucose monitoring
• It's not suitable for people without a confirmed diabetes diagnosis.

Diabetes affects around 4.3 million people in the UK, with approximately 90% having type 2 diabetes. Continuous glucose monitoring may be recommended for:

• people with type 1 diabetes
• some people with insulin-treated type 2 diabetes
• people experiencing frequent hypoglycaemia
• pregnant women with diabetes

Always speak to your GP or diabetes specialist to confirm suitability.

What is FreeStyle Libre 3 Plus continuous glucose monitoring used for?

FreeStyle Libre 3 Plus is used to monitor glucose levels continuously throughout the day and night to support diabetes management. It helps identify trends, patterns and fluctuations in glucose levels.

The system measures glucose every minute and updates readings automatically in the app. This supports:

adjusting insulin doses

• understanding the impact of meals and exercise
• detecting nocturnal hypoglycaemia
• reducing time spent in hyperglycaemia

Maintaining glucose within your target range can help reduce long-term complications like cardiovascular disease, which people with diabetes are at higher risk of developing.

How to use FreeStyle Libre 3 Plus

FreeStyle Libre 3 Plus is applied to the back of the upper arm and worn continuously for up to 15 days.

To use your FreeStyle Libre 3 Plus sensor, you should:

• Wash and dry your hands.
• Choose a comfortable spot on the back of your upper arm and clean the area with the provided alcohol wipe.
• Apply the sensor using the applicator provided in the pack.
• Start the sensor using the FreeStyle Libre 3 app on your compatible smartphone.
• Wait for the warm-up period (usually around 60 minutes).
• Monitor readings in real time via the app.

The sensor is water-resistant and can generally be worn while showering, swimming, or exercising, but it should not be submerged deeper than the manufacturer's guidance allows.

If the sensor becomes loose, painful or falls off before 15 days, contact the manufacturer or your pharmacist for advice.

Where to buy FreeStyle Libre 3 Plus in the UK

FreeStyle Libre 3 Plus is a prescription-only medical device in the UK. It can be obtained through the NHS if you meet eligibility criteria, or privately with a valid prescription.

You can request the FreeStyle Libre 3 Plus online from Chemist4U by completing a short questionnaire, which will be reviewed by one of our pharmacists before your order is approved.

How long will it take Libre 3 Plus to take readings?

FreeStyle Libre 3 Plus measures glucose levels every minute and continuously updates your smartphone with real-time readings. There is a short warm-up period of approximately 60 minutes after application before data becomes available.

Continuous readings allow for better detection of rising or falling glucose trends compared to traditional testing, giving you more control and insight when managing your condition.

What’s the difference between Libre 2 Plus and 3 Plus?

FreeStyle Libre 3 Plus offers fully automatic, real-time data transmission without scanning, making it more streamlined for users who prefer continuous updates. This means it differs from FreeStyle Libre 2 Plus, which requires scanning to work.

Potential side effects of FreeStyle Libre 3 Plus

Most people tolerate FreeStyle Libre 3 Plus well, but mild skin reactions may occur at the application site. These reactions are usually temporary. However, remove the sensor and seek medical advice if you experience:

• redness
• itching
• mild swelling
• skin irritation

Seek urgent medical help if you have:

• Signs of severe allergic reaction (anaphylaxis): Rash, swelling of the face or throat, difficulty breathing.
• Symptoms of severe hypoglycaemia: Confusion, seizures, unconsciousness.
• Persistent high glucose readings: With symptoms like vomiting or abdominal pain (possible diabetic ketoacidosis in type 1 diabetes).

The NHS advises urgent medical attention for severe hypo symptoms or suspected diabetic ketoacidosis.

How to store Libre 3 Plus

Store unused sensors at room temperature, away from direct heat and moisture.

Do not use the sensor after the expiry date printed on the packaging. Keep out of reach of children.

Do not refrigerate unless specified by the manufacturer’s instructions. Always check the patient information leaflet supplied with the product.

Frequently asked quesitons about FreeStyle Libre 3 Plus

Is Libre 3 Plus water-resistant?

Yes, Libre 3 Plus is water-resistant and can be worn while showering, swimming and exercising within manufacturer guidelines. Avoid prolonged submersion or high-impact water activities.

How do I connect it to the app?

Download the FreeStyle Libre 3 app from your device’s app store, enable Bluetooth, and follow on-screen instructions to start your sensor. Your phone must be compatible and kept within range to receive continuous updates.

How long does the Libre 3 Plus battery last?

The battery lasts for the full 15-day lifespan of the sensor. It's built into the disposable sensor and does not require charging.

Once the 15-day wear period ends, the sensor will stop transmitting data and must be replaced with a new one.

What happens if the Libre sensor falls off?

A sensor that has been removed or that has accidentally fallen off cannot be reused. Users should replace the Libre 3 sensor and start a new sensor. The FreeStyle LibreLink app or reader will automatically identify that It's a new sensor and ask users if they want to start it.

How many days can you wear FreeStyle Libre 3 Plus?

The FreeStyle Libre 3 Plus has a wear time of 15 days, after which point it will need to be removed and replaced with a new sensor.

Do I need to calibrate the FreeStyle Libre 3?

No, the sensor is calibrated during the manufacturing process, so you don't have to. The Sensor is activated by scanning, and then, after an initial warming period, it begins to record glucose readings automatically.

Do I still have to prick my finger?

Finger pricks are only required if your glucose readings and alarms do not match symptoms or reading expectations.

Sources

• Diabetes. (2023). NHS. [Accessed 10 March 2026].
• Hypoglycaemia (low blood sugar). (2023). NHS. [Accessed 10 March 2026].
• Type 1 diabetes in adults. (2022). NICE. [Accessed 10 March 2026].
• Type 2 diabetes in adults. (2022). NICE. [Accessed 10 March 2026].