Insulin production marker
C-Peptide — Residual Insulin Secretion
Also searched as C-Peptide — Residual Insulin Secretion.
You want it preserved: residual C-peptide means fewer severe hypos and gentler long-term complications.
In depth
C-peptide is released with insulin in equal amounts, so it measures how much insulin a person is still making themselves. In type 1 it is the honest readout of surviving beta-cell mass, and preserving it is the realistic goal where reversal is not.
What drives it
Protects insulin cells increases it.
10.1007/s13300-017-0265-4 — C-peptide is co-secreted with insulin in equimolar amounts, so it reads surviving beta-cell function directly. The Novara cohort measured exactly this as 'residual endogen insulin secretion (REIS)' during the honeymoon phase (doi 10.3390/nu11092158). C-peptide reflects function, not cell count - a stressed but living beta cell can under-secrete. doi 10.1007/s13300-017-0265-4
Beta-cell renewal increases it.
New beta cells make insulin, and C-peptide is how you would know. Harmine 'increases expression of key beta cell transcription factors (PDX1, NKX6.1, MAFA, MAFB, NeuroD1) and phenotypic markers (GLUT2, PCSK1, GLP-1R, SLC30A8/ZnT8)' - the new cells are functionally beta, not merely insulin-positive. C-peptide would be the human readout; no human trial of any regenerative agent has reported it.
What it drives
It reduces Type 1 diabetes.
Preserved residual secretion is the realistic goal in established type 1. Verbatim: 'about 80% of children and adolescents experience a partial remission, reducing insulin demands to maintain euglycemia. Afterwards, a resumption of the autoimmune process determines a progressive growth of insulin requirements and brings the so-called honeymoon phase of T1D to an end' (doi 10.3390/nu11092158). The link runs inversely: more residual C-peptide means less disease burden - it does not mean the disease is reversed, and it never removes the need for insulin. doi 10.3390/nu11092158
Blends that modulate it
Each blend page names this pathway and carries the study behind its claim.
See it on the map
Open the causal map to follow this pathway upstream and downstream, arrow by arrow, each with its study.