What is C-peptide?
your body's own insulin production
C-peptide is released alongside insulin and shows how much insulin the pancreas itself is producing. It helps distinguish between types of diabetes.
The test is especially useful when the type of diabetes is unclear. Because it is not affected by injected insulin, it shows the body's true endogenous insulin output.
Test facts
- Unit
- nmol/L
- Sample
- Serum
- Fasting
- 8 hours
- Turnaround
- 3 days
What does low C-peptide mean?
Low C-peptide reflects reduced insulin production, as in type 1 diabetes or long-standing type 2.
What does high C-peptide mean?
High C-peptide reflects insulin resistance, where the pancreas compensates by producing more insulin.
Panels that measure C-peptide
- Diabetes & Metabolic
- Metabolic Deep Dive
More markers in the same area
Launching in Stockholm in 2026.
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This is general information about the marker, not an assessment of your values and not medical advice. Last updated: May 2026.