Phone showing a glucose graph held in front of an arm with a white sensor patch

Diabetes Technology: CGMs, Insulin Pumps and Apps Explained

Key Takeaways

  • The ADA recommends a continuous glucose monitor (CGM) for children and adults with diabetes who use insulin or take other medicines that can cause a low.[1]
  • Over-the-counter CGMs have been sold in the US since 2024. They have no alarms and are meant for adults who do not use insulin.[1][2][3]
  • For people with type 1 diabetes, and people with type 2 diabetes who use insulin, the ADA prefers automated insulin delivery over injections or a standard pump.[1]
  • The ADA suggests pairing devices and apps with licensed coaching.[1]

Diabetes technology covers the devices that measure glucose and deliver insulin, plus the apps that collect the data. The main tools are continuous glucose monitors (CGMs), insulin pumps and automated insulin delivery systems, which link the two. The American Diabetes Association (ADA) reviews the evidence on these devices every year, and its 2026 guidance is the main source for this article.[1]

Which device suits you depends on your type of diabetes and your treatment, and each one is explained below in plain terms. This guide is general education. If you use insulin or other glucose medicines, follow the plan your diabetes team gave you.

What is a continuous glucose monitor (CGM)?

A CGM is a small sensor worn on the skin that reads glucose in the fluid under the skin throughout the day and sends the result to a phone or reader. A finger-prick meter gives one reading at one moment. A CGM shows the trend through the day and night.

The ADA recommends a CGM from diagnosis onward for children and adults who use insulin or who take other medicines that can cause a low.[1] It also advises that CGM users learn which substances and other factors can affect accuracy.[1] Its list includes acetaminophen (paracetamol) above 4 g (0.14 oz) a day with some Dexcom sensors, vitamin C above 500 mg (0.018 oz) a day with some FreeStyle Libre sensors, and hydroxyurea. Each of these can make a sensor read higher than your actual glucose.[1]

Because a CGM reads fluid rather than blood, it can trail blood glucose by several minutes. In adults with type 1 diabetes this delay had a median of 6.8 minutes.[4] Our guide to normal blood sugar levels covers how CGM readings compare with finger-prick checks.

Because of this lag and possible interference, the ADA says a finger-prick meter is still needed to confirm a CGM reading, especially when the reading does not match how you feel.[1] Lows are more likely if you use insulin or a sulfonylurea such as gliclazide or glimepiride, and low blood sugar usually means below 4 mmol/L (72 mg/dL) in the UK or below 70 mg/dL (3.9 mmol/L) in the US.[5][6] In the UK, the NHS says to call 999 if someone may have very low blood sugar and is not responding normally or is unconscious, and a glucagon injection is not available or you do not know how to use it, or they have not recovered within 10 minutes of a glucagon injection, or they have been drinking alcohol.[5] In the US, the ADA says to call 911 right away if someone is unconscious and glucagon is not available or no one knows how to use it.[6]

Can I buy a CGM without a prescription?

In the US, yes, if you do not use insulin. In March 2024 the FDA cleared the first over-the-counter CGM, the Dexcom Stelo, for adults aged 18 and over who do not use insulin. The FDA notes it is not for people with problematic lows, because it does not alert the user to them.[2] In June 2024 Abbott announced FDA clearance for two more over-the-counter systems, Lingo and Libre Rio.[3]

The ADA describes over-the-counter CGMs as lacking alarms and alerts, and as suitable for people not taking diabetes medicines that raise the risk of a low.[1] If you use insulin, a prescribed CGM with alerts is the type the ADA recommends. Rules on access differ outside the US. In England, NICE guidance says adults with type 1 diabetes should be offered a CGM.[7] For type 2 diabetes, it covers adults on several daily insulin injections who meet set criteria, such as repeated lows.[8] Ask your own healthcare team what is available to you.

Pro Tip

Before you buy a sensor, write down what you want to learn from it, such as how a usual breakfast or an evening walk affects you. Then share the data with your team so the numbers lead to a decision.[1]

Insulin pump vs injections: what does the ADA prefer?

If you use insulin, there are three main ways to deliver it: several daily injections, a standard insulin pump, or a pump linked to a CGM. The ADA now prefers automated insulin delivery (AID) over injections, standard pumps and sensor-augmented pumps for people with type 1 diabetes, adults, children and adolescents with type 2 diabetes who use insulin, and others whose diabetes is insulin deficient.[1]

It also suggests considering AID for some people with type 2 diabetes on basal insulin who are not reaching their goals.[1]

The choice still depends on cost, access, your own preferences and how comfortable you are with the device. Your diabetes team can talk you through the options.

What is a hybrid closed loop system?

A hybrid closed loop is the most common type of AID system. Software uses the CGM readings to adjust the insulin the pump delivers. It is called hybrid because the user still has to tell the system about meals. The ADA notes that current AID systems still need meals entered by hand.[1]

A review of 65 trials with 3,623 people with type 1 diabetes found that AID raised time in range by 11.74 percentage points compared with other treatments.[9] That works out to about 2.8 extra hours a day in range (our arithmetic: 11.74% of 24 hours).

Results also vary between systems. A review of real-world data from 34 studies found average time in range from 60.1% to 73.9%, depending on the system.[10] For a sense of these numbers, the ADA suggests more than 70% time in range (70 to 180 mg/dL, or 3.9 to 10.0 mmol/L) as a goal for many nonpregnant adults.[6]

When we read the 2026 ADA technology section for this guide, the point that stood out was its preference for automated insulin delivery over standard pumps. The table below sums up the main devices, based on the ADA standards.[1]

Device. What it does. Who it suits.
Finger-prick meter.[1] Measures glucose in a drop of blood at one moment.[1] Anyone who needs spot checks, and for confirming a CGM reading when symptoms do not match.[1]
Prescribed CGM.[1][7][8] Reads glucose under the skin through the day, with alerts for highs and lows.[1] People who use insulin or take medicines that can cause a low.[1][7][8]
Over-the-counter CGM (US).[1][2][3] Reads glucose under the skin, without alarms.[1][2] Adults aged 18 and over who do not use insulin.[1][2][3]
Standard insulin pump.[1] Delivers insulin at rates you set.[1] People who use insulin and prefer a pump to multiple daily injections.[1]
AID (hybrid closed loop).[1][9][10] Pump and CGM linked, software adjusts insulin, meals still entered by hand.[1] Preferred by the ADA for type 1 diabetes and for type 2 diabetes treated with insulin.[1]

Are diabetes apps worth using?

Apps can collect data from meters, CGMs and pumps in one place. The ADA suggests combining technology such as CGMs, pumps or apps with online or virtual coaching from a licensed professional for people with diabetes or prediabetes.[1] The data is more useful when a professional helps you act on it.

Apps can also log the habits that affect your readings, such as exercise and sleep. If you do not use insulin, the ADA notes that finger-prick checks have not consistently improved A1C, though they can help when your plan is being adjusted.[1]

  1. Check with your diabetes team or GP whether you qualify for a prescribed CGM, insulin pump or hybrid closed loop system under NHS/NICE or US insurance rules.[1][7][8]
  2. Keep a finger-prick blood glucose meter and in-date test strips on hand to confirm CGM readings whenever your symptoms do not match the screen.[1]
  3. Tell your care team if you take acetaminophen (paracetamol) above 4 g (0.14 oz) a day, vitamin C supplements above 500 mg (0.018 oz) a day, or hydroxyurea, as these can skew certain sensors.[1]
  4. Share your CGM, pump or app reports with a licensed diabetes educator or clinician before changing your insulin doses.[1]

Questions to ask your diabetes team

  • Do I qualify for a prescribed CGM or an automated insulin delivery (hybrid closed loop) system on the NHS or through my insurance?[1][7][8]
  • Which over-the-counter medicines or supplements I take could interfere with my specific CGM sensor?[1]
  • How should I set my high and low glucose alerts, and when should I double-check my sensor with a finger-prick meter?[1][6]
  • Can we review my time-in-range and overnight CGM trends together before adjusting my insulin or sulfonylurea doses?[1][6]

Frequently asked questions

Who should use a CGM?

The ADA recommends a CGM for people with diabetes who use insulin or who take other medicines that can cause a low. Over-the-counter models in the US are for adults who do not use insulin.[1][2][3]

Does an over-the-counter CGM warn you about lows?

No. The ADA says over-the-counter CGMs lack alarms and alerts, and the FDA says the Dexcom Stelo is not for people with problematic lows.[1][2]

What is the difference between an insulin pump and a closed loop system?

A standard pump delivers insulin at the rates you set. A closed loop, or AID, system links the pump to a CGM, and software adjusts the insulin based on the readings.[1]

Do diabetes apps help?

The ADA suggests using apps and devices together with online or virtual coaching from a licensed professional, rather than on their own.[1]

Where to go next

To put diabetes technology readings in context, see:

Note: If you are pregnant, breastfeeding, or considering giving any supplement or herbal product to a child, consult your healthcare provider before making any changes to your diet, supplement routine, or prescribed medications.

Disclaimer: These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Talk to your doctor before changing your diet, your activity or your medicines, and before starting any supplement.

Sources & References

  1. American Diabetes Association Professional Practice Committee. (2026). 7. Diabetes Technology: Standards of Care in Diabetes 2026. Diabetes Care. pubmed.ncbi.nlm.nih.gov/41358889 Funding: none listed on the PubMed record. COI: Duality of interest information for each contributor is available at https://doi.org/10.2337/dc26-SDIS.
  2. U.S. Food and Drug Administration. (2024). FDA Clears First Over-the-Counter Continuous Glucose Monitor. fda.gov Funding: not applicable, this is official guidance, not a funded study.
  3. Abbott. (2024). Abbott Receives U.S. FDA Clearance for Two New Over-the-Counter Continuous Glucose Monitoring Systems. abbott.mediaroom.com Funding: corporate press release from Abbott, manufacturer of Lingo and FreeStyle Libre systems. COI: commercial manufacturer announcement.
  4. Basu, A., et al. (2015). Time lag of glucose from intravascular to interstitial compartment in type 1 diabetes. Journal of Diabetes Science and Technology. pubmed.ncbi.nlm.nih.gov/25305282 Funding: NIH grants DK029953 and DK085516. COI: the authors declared no potential conflicts of interest.
  5. NHS (reviewed 3 August 2023). Low blood sugar (hypoglycaemia). Accessed 1 November 2026. nhs.uk Funding: not applicable, this is official guidance, not a funded study.
  6. American Diabetes Association Professional Practice Committee. (2026). 6. Glycemic Goals, Hypoglycemia, and Hyperglycemic Crises: Standards of Care in Diabetes 2026. Diabetes Care. pubmed.ncbi.nlm.nih.gov/41358894 Funding: none listed on the PubMed record. COI: Duality of interest information for each contributor is available at https://doi.org/10.2337/dc26-SDIS.
  7. National Institute for Health and Care Excellence. (2015, updated 2022). Type 1 diabetes in adults: diagnosis and management (NG17), recommendation 1.6.10. nice.org.uk Funding: not applicable, this is official guidance, not a funded study.
  8. National Institute for Health and Care Excellence. (2015, updated 2022). Type 2 diabetes in adults: management (NG28), recommendation 1.7.1. nice.org.uk Funding: not applicable, this is official guidance, not a funded study.
  9. Fan, W., et al. (2025). Efficacy and Safety of Automated Insulin Delivery Systems in Patients with Type 1 Diabetes Mellitus: A Systematic Review and Meta-Analysis. Diabetes & Metabolism Journal. pubmed.ncbi.nlm.nih.gov/39533812 Funding: none listed on the PubMed record. COI: no potential conflict of interest relevant to this article was reported.
  10. Pƶhlmann, J., et al. (2026). A systematic literature review and meta-analysis of real-world evidence on commercially available automated insulin delivery systems in people with type 1 diabetes. Diabetes, Obesity and Metabolism. pubmed.ncbi.nlm.nih.gov/41058520 Funding: funded by Medtronic International Trading SƠrl. COI: several authors are employees of Ossian Health Economics and Communications (which received consulting fees from Medtronic) or employees and shareholders of Medtronic.
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