Sermorelin

Sermorelin is a linear 29-residue peptide with sequence YADAIFTNSYRKVLGQLSARKLLQDIMSR-NH2 — the first 29 residues of human growth-hormone-releasing hormone, terminated as the C-terminal amide. Molecular formula C149H246N44O42S, average mass approximately 3357.88 Da. CAS registry: 86168-78-7.

The 29-mer is the minimum fragment that retains full intrinsic GHRH-receptor agonist activity; the 30+ residues of the native 44-mer contribute primarily to half-life and tissue distribution. Sermorelin therefore has a much shorter plasma half-life than long-acting GHRH analogs such as CJC-1295.

Sermorelin is produced by Fmoc solid-phase peptide synthesis on a Rink-amide-style resin (to deliver the C-terminal amide). The main impurity sources are:

• Methionine oxidation at position 27. The single Met residue is highly susceptible to oxidation during synthesis, storage, and reconstitution; sulfoxide (+16 Da) and sulfone (+32 Da) variants are routine.
• Aspartimide and deamidation. The Asp-Met segment is a textbook aspartimide-formation site under repeated piperidine deprotection. Asn8 deamidates over storage to a mixture of α- and β-Asp.
• C-terminal truncations. Loss of the terminal Arg-NH2 produces des-Arg29 — a -156 Da analyte that is easy to confuse with the main product by intact mass alone if mass accuracy is poor.
• Loss of the C-terminal amide. Over-acidic cleavage hydrolyzes the amide to the free acid (-1 Da).

See common peptide impurities for the broader taxonomy.

The standard CertikLabs panel for a sermorelin batch:

• RP-HPLC purity (C18, 0.1% TFA / MeCN, UV 214 nm)
• LC-HRMS identity (ESI-Q-TOF, deconvoluted average mass against C149H246N44O42S)
• Tryptic peptide mapping with LC-MS/MS for sequence confirmation
• Quantitative AAA for content
• Met-oxidation screen by extracted-ion chromatograms (Δ+16, +32 Da)

Each method, including column, mobile phase, gradient, and detection conditions, is reported on the Certificate of Analysis so the result is reproducible. See how to read a peptide COA for what each section should contain.

Agonist at the GHRH receptor on pituitary somatotrophs, stimulating pulsatile growth-hormone release. Pharmacology is well established in the published GHRH literature.

Primary sources:

• Thorner M.O. et al., Growth hormone-releasing hormone and growth hormone-releasing peptide as therapeutic agents.(PMID 7768338)
• Prakash A., Goa K.L., Sermorelin: a review of its use in the diagnosis and treatment of children with idiopathic growth hormone deficiency.(PMID 10937325)

CertikLabs does not publish dosing, administration routes, or clinical recommendations for sermorelin.

Lyophilized sermorelin is generally stable refrigerated and protected from light. Reconstituted material is sensitive to Met(27) oxidation, deamidation at Asn/Gln, and aspartimide formation; pH, container, and oxygen exposure all influence stability and any working solution should be re-verified analytically.