bonj said:
Hmmm... I don't see how they know it's synthetic, if it's from his body and it's the same substance.
Pretty much any naturally occuring substance can be produced - and it is then synthetic. Becuase it isn't made within the body, it will have a different chemical constitution, even though it does a similar job within the body. Blood testing can therefore differentiate between endogenous & exogenous substances. Synthetic insulin can be open to sports abuse, and I have a feeling that there are tests available to differentiate between natural & synthetic insulin - I seem to recall this being used in the case against Beverley Allit in the early 1990's, as she used insulin to cause collapse in some of the infants she killed, and it was on subsequent review of blood tests that the insulin was detected.
Besides, biochemically the body will have a range of normal values, so grossly raised levels of any endogenous substance needs close examination because it usually indicates a further medical problem.