C-Peptide
Definition
A protein fragment released by the pancreas in a 1:1 ratio with insulin during the conversion of proinsulin to active insulin. C-peptide blood levels directly reflect how much insulin the body is producing endogenously, making it the standard test for distinguishing type 1 diabetes (low C-peptide) from type 2 diabetes (normal or high C-peptide). C-peptide has a longer half-life than insulin (30 minutes vs 5 minutes), providing a more stable measurement of pancreatic beta cell function.
Why “C-Peptide” Matters for Glucose Monitoring
Understanding c-peptide is essential for anyone using or evaluating a continuous glucose monitor. This concept directly affects how CGM devices are designed, how glucose data is interpreted, and how clinical decisions about blood sugar management are made.
This term applies broadly across all continuous glucose monitors and is foundational knowledge for interpreting CGM data, whether you are managing diabetes or using a sensor for metabolic wellness.
Related Terms
The insulin-producing cells located in the islets of Langerhans within the pancreas, responsible for sensing blood glucose levels and secreting the appropriate amount of insulin to maintain glucose homeostasis.
The blood insulin level measured after 8 to 12 hours without food, reflecting the baseline insulin output needed to maintain glucose homeostasis.
A metabolic condition in which the body's cells respond poorly to the hormone insulin, forcing the pancreas to produce progressively larger amounts to maintain normal blood glucose levels.