Comparison5 min read
Type 1 vs type 2 diabetes
Both are diabetes, but type 1 is autoimmune with little or no insulin production, while in type 2 the body responds poorly to insulin over time. Symptoms overlap; cause, onset and treatment differ.
In type 1, the immune system destroys the pancreatic cells that produce insulin and symptoms appear quickly, especially in children, so the person needs insulin. In type 2, insulin resistance develops gradually and then the pancreas cannot compensate, and there are often no symptoms at first. Both share thirst, frequent urination, tiredness and blurred vision.
Both types are diagnosed with glucose and A1C tests, and autoantibodies and C-peptide are added to confirm type 1 (NIDDK). Type 1 may first appear with ketoacidosis (NHS). In type 2, the plan often begins with lifestyle changes, with medicines depending on the case. Details are on the pages for each disease.
In one minute123
- What is it?
- A comparison of the two main types of diabetes in cause, onset, symptoms, diagnosis and treatment.
- Who is usually affected?
- Type 1 usually appears in children and young people, and type 2 usually in adults with risk factors.
- Acute or chronic?
- The first has a rapid onset and needs insulin; the second is slow and is managed with lifestyle changes and medicines.
- Main symptoms
- Thirst, frequent urination, tiredness, blurred vision and weight loss in both.
- Red flags?
- Yes: thirst, urination, abdominal pain, nausea, deep breathing and confusion in a person with diabetes may indicate ketoacidosis.
- Preventable?
- Lifestyle reduces the risk of type 2; for type 1, no way is mentioned in our sources.
The short version
Diabetes is a disorder in how the body uses glucose because of insulin. In type 1, the body produces little or no insulin because the immune system destroys the cells that make it, and in type 2, the cells do not respond to it as they should, with a gradual failure of secretion.
| Side | Type 1 | Type 2 |
|---|---|---|
| Cause | An autoimmune disease in which the immune system destroys the pancreatic cells that produce insulin | Insulin resistance in muscle, liver and fat, then gradual failure of secretion |
| Onset | Symptoms appear quickly in children and may develop gradually in some adults; it may first appear with ketoacidosis | Develops slowly over years, and many people notice no symptoms |
| Shared symptoms | Frequent urination, thirst, tiredness, blurred vision, slow-healing wounds, weight loss | Thirst, frequent urination, tiredness, blurred vision, weight loss, slow healing |
| What distinguishes the symptoms | Unexplained weight loss is mentioned in the sources under type 1 | CDC lists slow wound healing and numbness or tingling in the hands and feet under type 2 |
| Diagnosis | Plasma glucose and A1C, with autoantibodies and C-peptide to confirm type 1 | Plasma glucose, A1C and a tolerance test; antibodies are requested when there is doubt in order to distinguish between the two types |
| Treatment | Insulin according to the plan agreed by the treating team, with glucose monitoring | Lifestyle changes and medicines depending on the case, with metformin a common starting point for many people |
| Prevention | The sources for this page mention no way to prevent it | Lifestyle changes lower the likelihood of its appearing in people at risk (see the type 2 page) |
Symptoms: overlap and differences
NIDDK and CDC count excessive thirst, frequent urination, tiredness and blurred vision among the shared symptoms, and CDC mentions unexplained weight loss among the shared symptoms. CDC attributes slow wound healing and numbness and tingling in the hands or feet specifically to type 2.
Type 2 often causes no symptoms at the start, so it is sometimes discovered by chance (NHS).
Onset and acute risks
Type 1 may first appear as ketoacidosis (NHS), which is an emergency. Its symptoms according to the source pages: thirst, frequent urination, abdominal pain, nausea, deep breathing, fruity-smelling breath, tiredness and confusion.
When do you need urgent help?
Call emergency services now 998
- Thirst and frequent urination with abdominal pain, nausea, deep breathing, fruity-smelling breath or confusion in a person with diabetes: call an ambulance.7
See your doctor within days
Educational content only — no diagnosis, and no substitute for a clinician.
Common questions
Does type 2 turn into type 1?
No; they are different diseases in cause (autoimmune versus insulin resistance). NIDDK explains this.1
How does the doctor tell which type it is?
With glucose and A1C tests, and autoantibodies and C-peptide are added to confirm type 1 when it is suspected (NIDDK).2
Questions for your doctor
- Which type of diabetes do I have, and how did you confirm it?
- Do I need an antibody test?
- What treatment and follow-up plan is right for me?
- Which emergency warning signs should I watch for?
References
- 1NIDDK / NIH. What Is Diabetes?. www.niddk.nih.gov/health-information/diabetes/overview/what-is-diabetesHealth agencies & guidelines · Accessed 2026-10-03
- 2NIDDK / NIH. What is type 1 diabetes?. www.niddk.nih.gov/health-information/diabetes/overview/what-is-diabetes/type-1-diabetesHealth agencies & guidelines · Accessed 2026-10-05
- 3NHS. Type 1 diabetes. www.nhs.uk/conditions/type-1-diabetes/Health agencies & guidelines · Accessed 2026-10-06
- 4NIDDK / NIH. Symptoms & Causes of Diabetes. www.niddk.nih.gov/health-information/diabetes/overview/symptoms-causesHealth agencies & guidelines · Accessed 2026-10-03
- 5CDC. Symptoms of Diabetes. www.cdc.gov/diabetes/signs-symptoms/Health agencies & guidelines · Accessed 2026-10-06
- 6NHS. Type 2 diabetes. www.nhs.uk/conditions/type-2-diabetes/Health agencies & guidelines · Accessed 2026-10-03
- 7NHS. Diabetic ketoacidosis. www.nhs.uk/conditions/diabetic-ketoacidosis/Health agencies & guidelines · Accessed 2026-10-03
Review status: Edited content · Last updated:
Change log
- — Comparison created.
Educational content only — no diagnosis, and no substitute for a clinician.