What is type 1 diabetes?
Type 1 diabetes is a chronic, progressive autoimmune condition
That means it needs to be managed for life and it gets worse over time in stages. You can think of an autoimmune disease like a programming error in the immune system. The immune system is programmed to protect people from harmful threats. But with autoimmune type 1 diabetes, the immune system mistakenly thinks healthy cells, called beta cells, are a harmful threat and attacks them.
Beta cells make insulin—and people need insulin to convert blood sugar into energy. Insulin helps your body stay healthy. Without enough insulin, your blood sugar level stays higher than normal, and serious, potentially life-threatening complications like diabetic ketoacidosis (DKA) can happen.
This is also the point when lifelong lifestyle changes and insulin injections are needed.
What are beta cells?
They’re small but central to T1D
Beta cells produce insulin that helps regulate blood sugar levels. In T1D, part of your immune system begins mistakenly attacking these beta cells. When too many beta cells have been destroyed, your body is unable to make enough insulin to keep your blood sugar level within a healthy range. This can cause health complications over time.
By Stage 3 T1D, a significant number of beta cells have been damaged and the body can no longer make enough insulin on its own. At this point symptoms appear and daily insulin therapy becomes necessary. But even a small number of beta cells may help the body continue making some insulin, supporting steadier blood sugar levels with fewer highs and lows.
Watch the video to learn more about beta cells and why early screening matters.
Type 1 diabetes progresses in stages
Each stage is defined by how many beta cells remain. As more beta cells are lost your body becomes less able to produce insulin and in turn regulate blood sugar levels.
Stage
1
- Beta cell attack begins
- Blood sugars are within a normal range
- No visible signs or symptoms
- Insulin is not needed
- Presence of 2 or more T1D autoantibodies
Stage
2
- Beta cell attack continues
- Blood sugars are higher or lower than a normal range
- Still no visible signs or symptoms
- Daily insulin is not needed
- 2 or more T1D autoantibodies are present
Stage
3
- A significant number of beta cells have been damaged
- High blood sugar (hyperglycemia)
- Body no longer able to make enough insulin to control blood sugar levels
- 1 or more T1D autoantibodies may be present
- Visible signs and symptoms appear, and daily insulin dependence begins
*This stage is when type 1 diabetes is typically diagnosed
Stage
4
- Few-to-no beta cells remaining
- Long term T1D
- Dependence on external insulin to control blood sugar
- Health complications common
- T1D-related autoantibodies may no longer be present
- Daily insulin usage continues
What’s the honeymoon phase?
After a stage 3 T1D diagnosis, some people go through a short “honeymoon phase.” During this time, the pancreas may still make small amounts of insulin, which can make blood sugar a little easier to manage. The phase doesn’t last forever — it might be weeks or even months — but it can give you and your care team time to adjust, learn about T1D, and prepare for long-term management with daily insulin.
Researchers are studying new ways to address the progression of T1D including during or after the honeymoon phase. Talk to your doctor about what the latest research may mean for you.
The risks are real
Diabetic ketoacidosis (DKA) is a dangerous complication of autoimmune T1D. It can happen when the blood becomes acidic (when ketones are present) because the body doesn’t have enough insulin to let blood sugar into your cells. DKA can cause coma, brain damage, and even death.
T1D diagnoses often come without warning, in potentially traumatic settings like an emergency room. But you don't have to be caught off guard! Screen and spot T1D early.
This content was last reviewed in June 2026