drtbear1967
Musclechemistry Board Certified Member
Drug testing for rHGH as a performance enhancer is relatively new and there is a lot of misconceptions about how it works. I figured it was worth a post. Endogenous GH(naturally produced) exists in several different isoforms. An isoform is a slight modification to the parent compound. These modifications can happen during mRNA splicing or post-translational modification. The latter means after the GH peptide is synthesized, different chemical reactions occur-such as N-acetylation or deamidation. These isoforms all have different molecular weights compared to synthetic HGH and herein lies the test. The drug test is a ratio test of normal 191 amino acid GH and all the different isoforms they are naturally produced. If the ratio is higher than 0.8, this could trigger a positive test. This is a blood test, not urine bc GH and metabolite are well below the limit of detection in urine, and must be taken within 48hr of use of HGH. There is a newer test called the biomarkers test which measures the byproducts that occur from taking synthetic HGH such as elevated IGF-1 and N-terminal peptide of protocollagen type III(both are increased in a dose-dependent manner). Supposedly, this test can detect synthetic HGH up to 3 weeks after discontinuation. This is also a blood test and can not detect these downstream effects within the first 48hr of use. Both of these methods are scientifically validated. Btw-sometimes athletes use GHRPs to mask use of rHGH via the isoform test. However, GHRPs can also be tested for via Mass Spectrometry, based on certain metabolites of each of these peptides. These metabolites are only detectable up to 47hr, with GHRP-2 being the longest.
