What is type 3c diabetes?

Diabetes is a condition where the amount of glucose in your blood (called your blood glucose or blood sugar level) is too high. There are different types of diabetes. You may have heard of type 1 and type 2 diabetes. Type 3c diabetes is different to these.

What is the difference between type 3c diabetes and type 1 and type 2?

Type 3c diabetes is different to type 1 diabetes and type 2 diabetes.

Your pancreas normally makes hormones called insulin and glucagon which keep your blood sugar at the right level. Pancreatic cancer or surgery can stop your pancreas making enough of these hormones.

• People with type 1 diabetes can’t produce any insulin but make normal levels of glucagon. People with type 3c diabetes may produce less of all the hormones from the pancreas, including insulin and glucagon. If you have had your whole pancreas removed, you won’t produce any insulin or glucagon.
• People with type 2 diabetes make insulin but it doesn’t work properly, and they need more to do the same job. In people with type 3c diabetes the insulin works properly but they don’t make enough of it.

The different types of diabetes need to be treated differently. This means that the usual treatment for type 1 or type 2 diabetes may not be right for you if you have type 3c diabetes. Most people with type 3c diabetes will need to take medicine to manage it.

If you already had type 1 or 2 diabetes before being diagnosed with pancreatic cancer, your diabetes may now need to be treated differently.

You may find that type 3c diabetes isn’t as well-known as type 1 or type 2. A lot of the information available about diabetes is for people with type 1 or 2 diabetes and may not be relevant to you. For example, there is a lot of information that encourages people with type 2 diabetes who are overweight to lose weight. This won’t be relevant to people with type 3c diabetes who have lost weight or are struggling to put weight back on.

Type 3c diabetes and problems digesting food

If you have type 3c diabetes, you are likely to also have problems digesting your food. This is because as well as insulin and glucagon, the pancreas also makes enzymes which break down (digest) your food. Pancreatic cancer can affect this process.

You can take capsules to replace the enzymes that your pancreas would normally make. This is called pancreatic enzyme replacement therapy (PERT) and will help you to digest your food.

If you have problems digesting your food, you won’t fully digest carbohydrates in your food. This means that less glucose will be absorbed into your blood. Once you start taking the pancreatic enzymes, your blood sugar level may rise because you will be digesting carbohydrates again.

This can change how your diabetes needs to be managed, and it may need to be monitored more regularly. If you notice your blood sugar levels have gone up, speak to your diabetes team as they may need to change your medicine. It’s important that blood sugar levels are treated with medicine and not by reducing how much PERT you take or how much food you eat.

Updated June 2026

Review date June 2029