Metabolic Health

C-Peptide, Serum

Optimal Result: 1.1 - 4.4 ng/mL.

Other names: insulin C-peptide, connecting peptide insulin, proinsulin C-peptide

C-peptide is a substance made in the pancreas, along with insulin.

What is insulin?

Insulin is a hormone that controls the body's glucose (blood sugar) levels. Glucose is your body's main source of energy. If your body doesn't make the right amount of insulin, it may be a sign of diabetes.

Why test for C-peptide?

C-peptide and insulin are released from the pancreas at the same time and in about equal amounts. So a C-peptide test can show how much insulin your body is making. This test can be a good way to measure insulin levels because C-peptide tends to stay in the body longer than insulin.

What does it mean if your C-Peptide, Serum result is too low?

A low level of C-peptide can mean your body isn't making enough insulin.

It may be a sign of one of the following conditions:

- Type 1 diabetes
- Addison disease, a disorder of the adrenal glands
- Liver disease

It may also be a sign that your diabetes treatment is not working well.

What does it mean if your C-Peptide, Serum result is too high?

A high level of C-peptide can mean your body is making too much insulin.

It may be a sign of one of the following conditions:

- Type 2 diabetes
- Insulin resistance, a condition in which the body doesn't respond the right way to insulin. It causes the body to make too much insulin, raising your blood sugar to very high levels.
- Cushing's syndrome, a disorder in which your body makes too much of a hormone called cortisol.
- A tumor of the pancreas

If you can test it, we can track it — all test results, including the ones from your favorite labs.

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