• Guest, the forum is undergoing some upgrades and so the usual themes will be unavailable for a few days. In the meantime, you can use the forum like normal. We'd love to know what you think about the forum! Take the 2025 Survey »

Type 2 C Peptide level.

S

sillyshe

Member
My C peptide was 350 which is in the lower part of the range. Does this mean I do not produce a lot of insulin?
 
It depends on what your BG was when done.. if you fasted and had low bg then your body does not need to produce much insulin so lower cpep levels

If you bg was higher than normal and it was a non fasting test then yes you may not be producing much insulin
 
Thank you. I was well fasted and FBG was 6.2. Just trying to suss out if I am insulin resistant.
 
sillyshe said:
Thank you. I was well fasted and FBG was 6.2. Just trying to suss out if I am insulin resistant.
Click to expand...

Typically if insulin resistant you would be high in coeptide as your body over produces insulin to try and cope with the resistance
 
sillyshe said:
My C peptide was 350 which is in the lower part of the range. Does this mean I do not produce a lot of insulin?
Click to expand...
You are certainly on the low end. Depending on the lab range below 300 pmol/l an antibody test would / should be done . Mind some labs suggest anything below 250. Did you ask for an antibody test to see if you are producing antibodies such as GAD.

Having Insulin resistance would mean your pancreas would produce more insulin to counter the insulin resistance and corresponding C-Peptides. So I think it very unlikely you have insulin resistance. Ed - Sorry that should be autoantibody test.
 
Last edited:
There should be a calculation on the Internet somewhere to feed the figures into.
e.g.
Fasting IR
One example - works with fasted numbers.

C-Peptide

Do you know what units your c-peptide reading is in?
It may need conversion to feed into the on line calculators.
 
Looking at the figures @LittleGreyCat i’m thinking they must be pmol/ls. Of course I might be wrong as they are low. A Normal C-Peptide range is I believe 500 - 800 pmol/Ls fasting. So they are low and out of range. Anything lower than 300 pmol/ls put you in the ball park for autoimmune diabetes I believe.
 
Thank you for reply. The CPeptide was 350 pmol/Ls fasted.
Does auto immune mean I am type 1?
 
sillyshe said:
Does auto immune mean I am type 1?
Click to expand...
Positive autoimmune tests would suggest T1 but at this stage you could have a relatively low cpeptide for a number of reasons, not just T1. For example, some people have T3c, low insulin production because of damage to the pancreas, whereas some long term T2s have low cpeptide due to a "tired pancreas" (whatever that means. And there are other types of diabetes. You'd really need an endocrinologist to look at your results and possibly do more tests before changing your T2 diagnosis.
 
Last edited:
How long have you been diagnosed T2? Do note that c-peptide tests can be very diet influenced. If you have been trying a low carb or keto diet to manage your T2, these may give an artificially low c-peptide result compared to a typical 100+ carbs gm/day regime.
As others have mentioned ideally you need to have antibodies testing as well to confirm a change in diagnosis to T1.

If you can afford to self fund a CGM that will give you loads more information as to how your body reacts to carbs.
 
You must log in or register to reply here.
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn More.…