C-peptide Helps Prevent Diabetes Complications

I am finding articles that indicate that very small amounts of C-peptide can protect against diabetes complications in the eyes and kidneys.

In the February, 2009 issue of Diabetes Care there is a report involving a study of 471 Type 1 diabetics. The subjects were born during the 1945-2004 time period and they had been examined one or more times during the years 1994-2004. Beta cell secretion was observed in some of the people who had been diabetic for a long time. It was found that there were fewer instances of microvascular complications among the Type 1 diabetics who had higher fasting C-peptide values. There were 41% fewer instances of microvascular complications among patients whose C-peptide values were at least 0.06. It should be noted that this pattern was not observed with macrovascular complications.

NOTE: Macrovascular diabetes complications include heart disease, stroke, and diseases in the larger arteries of the limbs. Microvascular complications pertain to the smaller blood vessels and include retinopathy, neuropathy and kidney failure.


hmm this is interesting. i didnt know type 1s even made c peptide still as it is an insulin byproduct. maybe that accounts for my early complications, when i was dx’d my doc tld me i had no insulin or cpeptide.

Type-1s don’t make any c-peptide - or they eventually don’t if newly diagnosed. The absence of c-peptide leads to complications according to the article. So, looks like you got it backwards.

John, did you see the information in the link? Some type 1’s do have some C-peptide even after many years of diabetes. The current theory is that is why some of us long term type 1’s have no complications even after so many years. This study is not the only one which supports this theory. Look at the following link.


I’ve never had a C-peptide test. Would be interesting to see if I’ve got any left after 36 years!

I found the following paragraphs the most interesting:
"Fasting C-peptide values were positively correlated with age at diagnosis and triglycerides, and negatively with diabetes duration and high-density lipoprotein cholesterol.

The prevalence of complications was high particularly in patients with a longer diabetes duration. Ninety percent of patients with a duration of at least 30 years had one or more microvascular complications and 22% had one macrovascular complication.

People with Type 1 diabetes and higher fasting C-peptide values had lower prevalence of microvascular complications independently of duration of diabetes.

The association was independent of individual cumulative haemoglobin A1c average suggesting that the effect could be directly due to the biological properties of C-peptide."

Does this mean we need a drug that mimics C-peptide?!

Someone should bring this to the attention of Medicare. Maybe I could then get an insulin pump. My last c-peptide test result was four tenths over their limit for a patient with kidney failure. That is less than half a point and a big NO.

I asked my endo about a c-peptide test about 6 months ago. She explained to me that they’re not done on type 1s (especially long-timers like us) because practitioners assume we don’t make any c-peptide if we don’t make any insulin. My understanding has been that c-peptide is simply the leftover component of insulin production after proinsulin splits. It’s supposedly useful in repairing cell damage, which would explain its correlation with a lack of complications to nerves/arteries/etc.

I would be curious to know if the patients in whom they observed residual c-peptide had more or less insulin sensitivity than those who didn’t. It could explain a lot toward why we all have differing dosage needs. I have trouble imagining that you could have type 1 for a significant number of years and still make enough (any) insulin to either produce c-peptide and/or keep your islets from atrophying. But I haven’t read Richard’s links yet. laughs I’ll go do that now.

Melissa and Tim, there are more and more studies that are finding long term type 1’s who still have active beta cells and C-peptide. The Joslin team was amazed at the discovery. I can understand why some of the members here are hesitant to accept this. Doctors still say we do not produce any C-peptide because they do not keep up with the research. I feel certain that most T1’s do not produce any insulin, but some of us do. I am convinced that this explains why some of us do not develop complications. There are hundreds of long term type 1’s without complications, and many others with only mild complications. I have read that there are type 1’s who have not taken good care of themselves and yet they do not have complications after many years of type 1. There has to be a rational explanationn for this. I think that the presence of C-peptide is the explanation. I wll be finding out the results of my own report before the end of the year. I can’t wait.

My date for participating in this study in Boston is Nov 30. My wife and I will be in Boston Nov 29 & 30. If any of you live in the area it would be nice to meet you. Just let me know if you are interested.

The presence of triglycerides is also interesting in terms of diabetes duration and complications. So far, it looks like the lower the triglycerides, the better. I find that more immediately helpful than the C-peptide findings because right now we have exercise, food choices, and certain meds to help people with too-high triglycerides!

Richard,Are you going to the Denise Faustmann Study at massachusetts General Hospital? I am slated to go , the next week, in December 4-7, I do believe that many of us with limited complications may have a little c-peptide left… I need to read your link.

God BLess,

I see now you are going to the Joslin center, Richard…I wish you well.
God Bless

Brunetta, I am participating in the Joslin Medalist Study. They want to determine how some of us Type 1’s can live 50 years or more and have few or no complications.

my diagnosis was rocky, and my c-peptide test was negative… i assume it still is. there has been some talk of adding c-peptide to some of the synthetic insulins, but the manufacturers do not want to go through the fda again. (i understand the purpose of the fda, but do they have to make it so dang hard to do simple things?) if they add it to a bottle of humalog, they will have to go through the whole testing process (i think that is a 9 year average) and all of the millions in r&d yada yada yada… all for about 10% of their customer base. most of their insulin goes to type 2’s who mostly produce their own c-peptide… now we find out that a lot of type 1’s do as well?

Lev, there is a company in Sweden that has tested a product/drug that will enable Type 1’s to take C-peptide. It is not in the insulin though. It is taken separately. They have been sucessful with their clinical trials involving more than 100 subjects. They have now filed for a patent.