What is a pentapeptide?
A pentapeptide is a peptide composed of five amino-acid residues joined by peptide bonds. The catalog includes ipamorelin (Aib-His-D-2-Nal-D-Phe-Lys-NH₂), a synthetic pentapeptide growth hormone secretagogue with multiple non-standard amino acids for protease resistance.
What the research literature says
Pentapeptides sit in a useful size range for receptor-engagement-driven pharmacology — large enough to form specific receptor-binding interactions, small enough to be readily synthesised at low cost via solid-phase peptide synthesis. Ipamorelin’s pentapeptide structure includes the N-terminal aminoisobutyric acid (Aib, a non-standard amino acid blocking DPP-IV cleavage), histidine, two D-amino-acid substitutions for internal protease resistance (D-2-naphthylalanine and D-phenylalanine), and a C-terminal lysine with amide end-capping.
The combined modifications produce a ghrelin-receptor agonist with the ~2-hour plasma half-life characterised in the Johansen pharmacokinetic work (PMID 9879640) and the selectivity profile (high GH-release potency without confounding cortisol or prolactin elevation) characterised in the Raun first-selective-GHS paper (PMID 9849822). The combination of modifications represents the engineering strategy that makes pentapeptide-class GH secretagogues practical research and pharmaceutical tools.
The Ankersen development series and Hansen hybrid-structure work characterised related pentapeptide-class compounds with the same engineering framework (PMID 9733495, PMID 11459660), illustrating that the pentapeptide size range supports a broader class of GH secretagogue research compounds beyond ipamorelin specifically.
Why this matters in research context
The pentapeptide structural class matters in peptide-research contexts as the size class of ipamorelin — the catalog’s selective GH secretagogue. Researchers should understand that the pentapeptide size range supports engineered receptor-engagement pharmacology with end-capping plus internal modifications producing the practical pharmacokinetic and selectivity profile that distinguishes ipamorelin from earlier-generation GH secretagogues.
Related compounds
- Ipamorelin 10mg — the catalog pentapeptide
Related research questions
References
- Raun K et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol 1998;139(5):552-561. [PMID 9849822]
- Johansen PB et al. Pharmacokinetic evaluation of ipamorelin and other peptidyl growth hormone secretagogues with emphasis on nasal absorption. Xenobiotica 1998;28(11):1083-1095. [PMID 9879640]
- Ankersen M et al. A new series of highly potent growth hormone-releasing peptides derived from ipamorelin. J Med Chem 1998;41(19):3699-3704. [PMID 9733495]
Research-questions pages describe research-context use of peptide-research terminology. They do not constitute medical, veterinary, or clinical advice. Every compound in the Ronin catalog is sold strictly for laboratory and research use only.