Scientists discovered a new version of the growth‑hormone‑releasing peptide GHRP‑2 (a glycine‑substituted heptapeptide) in a seized vial. They used high‑resolution mass spectrometry to figure out its exact structure, showing that it’s a slightly different molecule that could slip past current doping tests. This tells the biohacking community that a novel, possibly undetectable GHRP‑2 analogue is already circulating on the black market.

Growth hormone releasing peptides (GHRPs) are synthetic peptides with the ability to stimulate human growth hormone (hGH) secretion. Several GHRPs have been developed as drug candidates; however, only one of them, GHRP-2 (Pralmorelin), has received a clinical approval. Nevertheless, they are distributed on the black market and misused by cheating athletes, due to their performance-enhancing effects. Hence, GHRPs have been included in the World-Anti-Doping-Agency's Prohibited List as forbidden substances in sport. Predominantly, analytical methods for detection and unequivocal identification of doping substances are based on mass spectrometry. Therefore, in the present work, a qualitative analysis by liquid chromatography coupled to high-resolution tandem mass spectrometry with a quadrupole time-of-flight analyzer was performed to identify a new heptapeptide (MW = 874.02 Da) - a glycine analogue of GHRP-2. Structure determination using de novo sequencing is described here in detail. The results of this study may indicate a new approach to circumvent a detection of doping practices.