It turns out that if a person wasn't producing C-Peptide and somehow is now, that is a Big Deal.
The two links below give different types of information. The second, about the C-Peptide Test, is the much easier one to read for the lay person.
This link gives a long
detailed, medical treatise on what C-Peptide is used for in the body including reducing inflammation, especially of the vascular (blood vessels) system. I have provided the Conclusions for a quick and dirty reference that having C-Peptide IS a good thing for the human body. CONCLUSIONS AND FUTURE OUTLOOK
From the multifaceted effects of C-peptide discussed above, it should be clear that the peptide can no longer be considered an irrelevant by-product of insulin biosynthesis. Its specific binding to cell membranes, its particular intracellular signaling pattern with end effects involving activation and enhanced expression of eNOS and Na+,K+-ATPase, and its activation of several important transcription factors all attest to the peptide being a bioactive endogenous peptide in its own right. Extensive studies in animal models of diabetes and early clinical trials in type 1 diabetic patients demonstrate that replacement of C-peptide results in beneficial effects on the diabetes-induced functional and structural abnormalities of peripheral nerves, the kidneys, and the brain. Much remains to be learned about C-peptide physiology, but even a cautious evaluation of the available evidence presents in plain sight the picture of a previously unrecognized endogenous peptide with therapeutic potential. Since no disease-modifying therapy is available for patients with microvascular complications of type 1 diabetes, it can be hoped that the ongoing development of a long-acting C-peptide (75) will facilitate further clinical trials and allow definition of C-peptide’s potential role in the therapy of type 1 diabetes.
C-Peptide uses in body - Link This link details the C-Peptide Test and what it reveals about the person being tested.
C-Peptide Test and uses of - Link