C-Peptide Unit Converter

C-peptide (connecting peptide) is a short chain of amino acids that your pancreas produces as a byproduct of making insulin. When proinsulin is split into active insulin, C-peptide is released in equal amounts.

Because C-peptide and insulin are released in a 1:1 ratio, measuring C-peptide provides a reliable window into how much insulin your body is making on its own. Unlike insulin, C-peptide is not significantly broken down by the liver and stays in the blood longer, making it a more stable and accurate marker of pancreatic beta-cell function.

C-peptide is especially useful in people who take insulin, since injected insulin does not contain C-peptide. This allows doctors to distinguish between insulin the body produces and insulin given as medication.

C-peptide is produced exclusively by the beta cells of the pancreas. It is cleaved from proinsulin during the final step of insulin production and released into the bloodstream alongside insulin.