Analysis of new growth promoting black market products. — VialBase Research

Summary

Researchers from anti-doping laboratories (German Sport University Cologne, Norwegian Doping Control Laboratory, and collaborators) analyzed new black-market products marketed as growth-promoting agents — substances positioned as human growth hormone (GH) or growth-hormone-releasing peptides (GHRPs) — using high-resolution/high-accuracy liquid chromatography-mass spectrometry. The analysis uncovered a previously undescribed modified isoform of GH: a 192-amino-acid variant carrying an extra N-terminal alanine residue (monoisotopic mass 22,195 Da vs. 22,124 Da for native 191-amino-acid GH), confirmed through both top-down and bottom-up MS workflows. Alongside this modified GH, three glycine-extended GHRP analogues were characterized: Gly-GHRP-6, Gly-GHRP-2, and Gly-Ipamorelin — each corresponding to a known GHRP but extended by an additional N-terminal glycine residue rather than matching the parent compound’s canonical sequence. The identities of Gly-Ipamorelin and Gly-GHRP-2 were independently verified by custom-synthesizing reference material and matching its mass-spectrometric signature. The authors also conducted preliminary in-vitro experiments to explore the potential metabolic fate of these compounds after administration.

Key Findings

• A previously unreported modified GH isoform (192 amino acids, +N-terminal alanine, monoisotopic mass 22,195 Da) was discovered in black-market growth-promoting products, confirmed by top-down and bottom-up high-resolution LC-MS/MS
• Three glycine-extended GHRP analogues — Gly-GHRP-6, Gly-GHRP-2, and Gly-Ipamorelin — were identified, each differing from the reference peptide by an added N-terminal glycine
• Structures were characterized using high-resolution tandem mass spectrometry
• Gly-Ipamorelin and Gly-GHRP-2 identities were confirmed by custom synthesis of matching reference standards
• Preliminary in-vitro work assessed the potential post-administration metabolism of these novel analogues

Relevance to Ipamorelin

This study did not analyze standard commercial ipamorelin in isolation — it was one of several GH-secretagogue-related substances characterized alongside a modified GH isoform, Gly-GHRP-6, and Gly-GHRP-2. The ipamorelin-related substance actually detected was Gly-Ipamorelin, an N-terminally glycine-extended structural analogue, not the canonical ipamorelin peptide itself. That distinction is the sourcing-relevant finding: in a rigorous forensic-analytical setting, black-market GH-secretagogue products were found to contain molecularly altered variants of the compounds they were purported to be — differing in sequence, and therefore potentially in receptor activity, pharmacokinetics, and safety, from the authentic reference substance. For anyone evaluating ipamorelin sourcing, this is direct analytical evidence that label claims alone cannot be trusted to indicate true peptide identity; independent mass-spectrometry verification (e.g., a vendor’s certificate of analysis) is the only reliable way to confirm a product contains authentic ipamorelin rather than an unverified analogue like Gly-Ipamorelin.

Citation

Krug O, Thomas A, Malerød-Fjeld H, et al. Analysis of new growth promoting black market products. Growth Hormone & IGF Research. 2018;41:1-6. doi:10.1016/j.ghir.2018.05.001.

See Also

• Parent compound: Ipamorelin