Type 2 Diabetes

Type 2 diabetes is the most common form of diabetes — the U.S. Centers for Disease Control and Prevention estimates it accounts for about 90–95% of all cases. It develops when the body's cells respond poorly to insulin and the pancreas can't keep up, so blood glucose runs high. This guide explains what type 2 diabetes is, how it's diagnosed, the targets that matter, the complications it can cause, how it's treated, and where continuous glucose monitoring and clinical decision-support fit. It's educational, not medical advice.

What type 2 diabetes is

Type 2 diabetes is a long-term condition of glucose regulation. At its core are two linked problems: insulin resistance, where muscle, liver, and fat cells respond less to insulin, and a gradual decline in the pancreas's ability to produce enough insulin to compensate. Glucose then builds up in the blood. It usually develops over years and is often preceded by prediabetes, the stage where glucose is elevated but below the diabetes threshold. It differs from type 1 diabetes, an autoimmune condition — see type 2 vs type 1 diabetes. Start with What is type 2 diabetes? for the plain-language overview, and type 2 diabetes symptoms for the signs that can appear.

How it's diagnosed, at a glance

The American Diabetes Association defines diabetes using standardized blood tests. Any one of the following meets the threshold:

• A1c ≥ 6.5% — a blood test reflecting average glucose over roughly 2–3 months.
• Fasting plasma glucose ≥ 126 mg/dL — measured after an overnight fast.
• 2-hour oral glucose tolerance test ≥ 200 mg/dL — after a standardized glucose drink.
• Random plasma glucose ≥ 200 mg/dL — in a person with classic symptoms of high blood sugar.

Apart from a clear symptomatic case, an abnormal result is normally confirmed with a repeat test before a diagnosis is made. Our full explainer covers the detail — see how type 2 diabetes is diagnosed — and you can put values in context with our overview of blood sugar level charts for type 2.

How it's managed

Management aims to keep glucose in a healthy range while lowering the risk of complications. It usually combines everyday habits — eating patterns, physical activity, sleep, and weight — with monitoring and, when needed, medication. A common A1c goal for many non-pregnant adults is below 7%, but the ADA stresses that targets should be individualised; see A1c targets in type 2 diabetes. Medications range from metformin, often a first-line option, to GLP-1 receptor agonists and other classes covered in our medications overview. For some people, glucose returns to the non-diabetes range without glucose-lowering medication — read type 2 diabetes remission. Day-to-day, most of the work happens between appointments, which is where managing type 2 between clinic visits comes in.

Where CGM and decision-support fit

A continuous glucose monitor (CGM) shows the shape of glucose through the day — not just single readings — which can add useful context for people with type 2 diabetes and their clinicians. Our guide to using a CGM with type 2 diabetes explains what a sensor can and can't show, and the broader CGM guide covers the technology. Endobits reads the patterns in glucose data as clinical decision-support under a clinician's oversight — it supports interpretation, it does not diagnose or treat. It is important to watch for hypoglycemia in type 2 diabetes, particularly with certain medications.

The full type 2 diabetes library

Sources

American Diabetes Association — Diagnosis & diagnostic criteria (A1c, FPG, OGTT, and random glucose).
Centers for Disease Control and Prevention — About Type 2 Diabetes.
NIH / NIDDK — Type 2 Diabetes.

Related hubs: Prediabetes guide · CGM guide · Glossary · All resources