Conditions we treat
Type 1 diabetes is an autoimmune condition in which the immune system destroys the insulin-producing beta cells of the pancreas. Without insulin, glucose builds up in the bloodstream, so everyone with type 1 diabetes needs insulin every day. It is most often diagnosed in children, teens, and young adults, but it can begin at any age. With modern insulins, glucose-monitoring technology, and experienced specialist support, people with type 1 diabetes can live full, active lives.
2.1 million
people in the U.S. have diagnosed type 1 diabetes
314,000
U.S. children and teens under age 20 have diagnosed type 1 diabetes
5–10%
of people with diabetes have type 1
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Type 1 diabetes usually begins long before symptoms appear. The immune system produces islet autoantibodies that gradually damage beta cells, and specialists now describe the disease in three stages: stage 1 (two or more autoantibodies with normal blood glucose), stage 2 (autoantibodies plus abnormal glucose, still without symptoms), and stage 3 (symptoms and a clinical diagnosis).
Type 1 diabetes is different from type 2 diabetes, in which the body still makes insulin but can’t use it effectively. Adults with type 1 diabetes are sometimes first labeled as having type 2, especially when symptoms come on gradually, so getting the classification right matters for choosing the correct treatment.
The exact trigger isn’t known. Genes play a role, and having a parent or sibling with type 1 diabetes raises your risk. Researchers are also studying environmental factors such as viral infections. Type 1 diabetes is not caused by eating sugar or by lifestyle choices, and there is currently no known way to prevent it.
People with type 1 diabetes are more likely to develop other autoimmune conditions, particularly autoimmune thyroid disorders and celiac disease. Periodic screening for these conditions is a routine part of good type 1 care.
Once the disease reaches stage 3, symptoms can develop quickly, over a few weeks or months. Watch for:
Diabetes is confirmed with the same blood tests used for all types: an A1C of 6.5% or higher, a fasting plasma glucose of 126 mg/dL or higher, a 2-hour oral glucose tolerance test result of 200 mg/dL or higher, or a random glucose of 200 mg/dL or higher with classic symptoms. Islet autoantibody tests then help confirm that the diabetes is autoimmune, and a C-peptide test can show how much insulin your body still makes.
Relatives of people with type 1 diabetes may be offered autoantibody screening to find the disease in its early stages. For eligible people aged 8 and older with stage 2 type 1 diabetes, an FDA-approved medicine called teplizumab can delay the onset of stage 3 disease. The NIDDK’s type 1 diabetes overview explains screening and treatment in more detail.
Insulin is the foundation of treatment. It is given either as multiple daily injections, combining long-acting (basal) insulin with rapid-acting insulin at meals, or through an insulin pump. Doses are matched to food, activity, illness, and stress, which is why education and regular fine-tuning matter so much.
Technology has transformed daily management. The American Diabetes Association’s Standards of Care in Diabetes recommend offering continuous glucose monitoring (CGM) and automated insulin delivery systems, which link a CGM to a pump that adjusts insulin automatically, to people with type 1 diabetes who can use them safely. Your care team will set personal targets, which often include:
A goal below 7% is appropriate for many adults, adjusted for age, health, and hypoglycemia risk
Many adults aim for more than 70% of CGM readings between 70 and 180 mg/dL, with less than 4% below 70 mg/dL
Fast-acting glucose on hand at all times, and a glucagon prescription for everyone who takes insulin
Before each visit, we ask you to share data from your CGM, pump, or meter so your appointment can focus on decisions rather than downloads. Together we look for patterns such as overnight lows, post-meal spikes, or early-morning rises, then adjust basal rates, insulin-to-carbohydrate ratios, and correction doses.
Your endocrinologist also reviews your sick-day and ketone plan, checks your hypoglycemia preparedness, and orders routine labs, including A1C, kidney function, cholesterol, and thyroid tests. We coordinate with your primary care doctor, diabetes educators, and dietitians, and support teens moving from pediatric to adult care. Many follow-ups work well as virtual visits, and you can book an in-person or virtual appointment whenever you’re ready.
Plan insulin and snacks around activity, and check glucose before, during, and after longer workouts
Confirm your glucose is in a safe range before you drive, and keep fast-acting carbohydrates in the car
Reaching your glucose targets before conception lowers risks for you and your baby; this is different from gestational diabetes, which first appears during pregnancy
Diabetes distress and burnout are common, and asking for support is part of good care
Keep up with dilated eye exams, foot exams, and kidney screening
Not yet. Type 1 diabetes can’t be reversed with diet, exercise, or supplements, and insulin remains essential. Research into immune therapies, islet cell replacement, and stem cell–derived treatments is active, and one approved medicine, teplizumab, can delay the onset of clinical type 1 diabetes in some people identified at an early stage. Ask your endocrinologist whether a clinical trial might be right for you.
Yes. Type 1 diabetes is often diagnosed in childhood, but it can begin at any age. In adults it sometimes develops more slowly and is mistaken for type 2 diabetes at first. If you are not responding to type 2 medicines, are losing weight without trying, or needed insulin soon after diagnosis, ask your clinician about islet autoantibody testing to confirm your diabetes type.
A CGM isn’t mandatory, but for most people with type 1 diabetes it provides far more useful information than occasional finger sticks, including overnight patterns, trends, and alerts for highs and lows. The American Diabetes Association recommends offering CGM to people with type 1 diabetes. A standard meter is still helpful for confirming readings when your symptoms don’t match the sensor.
Illness can raise glucose and increase the risk of diabetic ketoacidosis, even if you’re eating less. Don’t stop your basal insulin unless your care team tells you to. Check glucose and ketones more often, drink plenty of fluids, and follow your written sick-day plan. Seek urgent care for persistent vomiting, trouble breathing, confusion, or moderate to large ketones.
Yes. Type 1 diabetes follow-ups often work well as virtual visits because CGM, pump, and meter data can be shared before your appointment. Your endocrinologist reviews the reports with you, adjusts settings, and orders labs you can complete locally. An in-person visit may be recommended for new device training, foot exams, or checking injection and infusion sites.
Last reviewed September 19, 2026. This page is educational and is not a substitute for personal medical advice — see our medical disclaimer.
Related conditions
The most common form of diabetes. We personalize medications, glucose monitoring, and lifestyle plans to protect your heart, kidneys, and eyes.
Higher-than-normal blood sugar that rarely causes symptoms. Acting early can lower your chances of developing type 2 diabetes.
High blood sugar that first appears in pregnancy. We work with your OB team on glucose targets, insulin if needed, and postpartum follow-up.
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Whether you’ve just been diagnosed or have managed diabetes or a thyroid condition for years, a TopInspired specialist can help you understand your numbers and build a plan that fits your life.
