C-peptide was discovered in 1967. The first actual use of a C-peptide test was in 1972. In more recent times, C-peptide has been found to have an effect on microvascular blood flow and tissue health.
Type I diabetics typically have very low levels of C-peptide because most of their beta cells have been destroyed. This has been seen in the development of long-term complications such as peripheral and autonomic neuropathy. I have experienced both kinds of neuropathies, but neither type has proved to be particularly problematic after 74 years of type 1.
C-peptide has been shown to significantly improve nerve and kidney function. It has also been reported to have anti inflammatory effects as well as aid repair of smooth muscle cells.
When experimenting with type 1 diabetics who lacked sufficient C-peptide, improvements were seen on diabetic peripheral neuropathy, nephropathy and other complications associated with long-term type I diabetes. Dosing with C-peptide was shown to be safe and there were no effects of C-peptide demonstrated.
The quotes given below were found in my online research:
"Newly diagnosed diabetes patients often get their C-peptide levels measured as a means of distinguishing between type 1 diabetes, Maturity Onset Diabetes of the Young (MODY), Latent Autoimmune Diabetes of Adults (LADA) and type 2 diabetes."
"The pancreas of a type 1 diabetic does not usually produce adequate insulin, so a decreased level of C-peptide is expected. Some secretion can still be present during the honeymoon stage for type 1 diabetics.
C-peptide levels in type 2 diabetics are normal, or even higher than normal. Determining the amount of C-peptide in people who inject or pump synthetic insulin can help to determine how much of their own natural insulin these patients are still producing, or if they produce any at all."
"The results of a C-Peptide test can vary from lab to lab. So different labs may have different 'normal' ranges. Doctors will sometimes evaluate your results based on your health and other factors. A C-Peptide value that falls outside the normal range may still be normal for you. The C-Peptide and blood glucose levels are measured at the same time to give a better evaluation.
A normal C-peptide level may be indicated as – Fasting: 0.51-2.72 nanograms per milliliter (ng/mL) or 0.17-0.90 nanomoles per liter (nmol/L)"
The first 725+ participants in the Joslin Medalist Study (2005-2015) were tested for their C-peptide levels. That test along with a glucose tolerance test showed that more than 66% of these long term diabetics did still produce some of their own insulin. My C-peptide level was less than 0.1, showing that my good health after 74 years of diabetes has to be explained by factors other than insulin secretion.
"Persons with LADA typically have low, although sometimes moderate, levels of C-peptide as the disease progresses and high blood glucose levels. The most common MODY syndrome may also have normal fasting C-peptide results because the flaw in this case is in the secretion of insulin in response to rising glucose and fasting secretion is still near normal.
Their postprandial C-peptide however is below normal with elevated blood glucose.
Low levels of both C-peptide and blood glucose are found in liver disease, a severe infection, Addison’s disease, or insulin therapy."
I have believed for several years that C-Peptide present in the animal insulins I used for 50 years may have protected me against certain complications. It may help explain the longevity and good health of most of the Joslin Medalists. Today's synthetic insulins do not contain any C-peptide. I have experienced several minor complications since starting synthetic insulins, but none of them have been particularly problematic. I asked Dr. King, head of the Joslin Medalist Study, about this. He said he does not think that C-peptide is a factor in explaining the longevity and good health of the medalists. Maybe he will have changed his mind as the research continues.
The link below is one of my references.
There was an attempt by a company called Cebix to produce an injectable form of C-peptide. The project failed during human trials. Here is some of the background of that project.
There does not seem to be any present day attempts being made to add C-peptide to insulin, and the attempt to produce an injectable form of C-peptide has failed. I am not aware that any other attempts are being made to provide us with C-peptide, but I have not given up hope. I am thinking that each individual could be tested and the appropriate amount of C-peptide needed could be determined. Then a prescription could be given that would enable that individual to inject that amount of C-peptide daily, weekly, or for an appropriate time schedule. That may seem far fetched, but I think there has to be a way for us to receive some of this potentially valuable substance.
What are your thoughts?