For laboratory research use only. This reference covers the structure, pharmacology and research history of sermorelin, the native GHRH(1-29) fragment. It is written in plain English for laboratory researchers and contains no dosing, administration or human-use guidance.
1. Overview
Sermorelin is the 29-amino-acid N-terminal fragment of human growth hormone-releasing hormone (GHRH), amidated at the C-terminus. It was the first GHRH fragment shown to keep the activity of the full 44-residue hormone and so became the reference molecule against which later GHRH analogues are compared [1, 3].
2. Structure
Sequence: YADAIFTNSYRKVLGQLSARKLLQDIMSR-NH2. Molecular formula C149H246N44O42S, average molecular weight about 3,358 Da, CAS 86168-78-7. The N-terminal region (residues 1 to 3) is needed for receptor activation, while the central helical region supports receptor binding. Sermorelin has no unnatural amino acids or protecting groups, which is why it is described as a “native” fragment.
3. Receptor pharmacology
Sermorelin is an agonist of the GHRH receptor, a class B G-protein-coupled receptor found mainly on pituitary somatotroph cells. Receptor activation couples to Gs, increases cyclic AMP and activates protein kinase A, which promotes GH gene transcription and release. Somatostatin opposes this signal, and IGF-1 provides negative feedback. Because sermorelin works through this normal control system, it is used in research on how GH release is regulated, rather than as a substitute for GH itself [1, 4].
4. Enzymatic stability
In plasma, DPP-4 removes the first two amino acids (Tyr-Ala), creating the inactive GHRH(3-29) fragment. Trypsin-like enzymes cut at arginine and lysine residues [2]. This rapid breakdown is the main structural difference between sermorelin and later analogues, which replace alanine at position 2 or block the N-terminus. In stored solutions, oxidation of methionine 27 is the main chemical degradation route.
5. Research history
- 1982–1983: GHRH was isolated from pancreatic tumours, and early studies characterised its selective effect on GH secretion [1].
- Late 1980s: work on plasma degradation identified DPP-4 as the key enzyme limiting the fragment’s stability [2].
- 1990s: a sermorelin acetate product was marketed as a prescription medicine in some countries; its clinical history is summarised in a 1999 review [3]. The product was withdrawn from the US market by the manufacturer in 2008.
- 2000s onward: sermorelin became mainly a reference compound in GHRH receptor and peptide-stability research, alongside reviews of GH secretion and ageing [4, 5].
6. Comparison with other GHRH analogues
| Compound | Length | Key structural change | DPP-4 resistance |
|---|---|---|---|
| Native GHRH | 44 aa | None (natural hormone) | No |
| Sermorelin | 29 aa | Truncated, C-terminal amide | No |
| CJC-1295 (without DAC) | 29 aa | Four amino acid substitutions incl. D-Ala2 | Yes |
| CJC-1295 with DAC | 29 aa + linker | As above, plus albumin-binding group | Yes |
| Tesamorelin | 44 aa | trans-3-hexenoyl group on the N-terminus | Yes |
See our tesamorelin research reference, CJC-1295 reference and MK-677 reference for related compounds.
7. Laboratory handling
- Store lyophilised powder sealed, cold (−20 °C for long-term storage), dry and protected from light.
- Let vials reach room temperature before opening to limit condensation.
- Prepare solutions with suitable laboratory solvents and calibrated equipment, and label each with lot number, concentration and date.
- Limit repeated freeze–thaw cycles and air exposure, which speed up methionine oxidation.
- Use the peptide calculator for concentration arithmetic (mg/mL).
8. UK research-grade sourcing standards
- Batch-specific certificate of analysis
- HPLC purity with chromatogram
- Mass spectrometry identity confirmation (about 3,358 Da)
- Low levels of Met27 sulfoxide and the GHRH(3-29) fragment
- Net peptide content, counter-ion and water content
Sermorelin acetate with batch documentation is listed on our sermorelin product page.
FAQ
Is sermorelin the same as GHRH?
No. It is the first 29 of GHRH’s 44 amino acids, with an amidated end. It keeps the receptor activity of the full hormone.
Why does sermorelin break down so fast?
Its unmodified alanine at position 2 is the preferred cutting site for the enzyme DPP-4 [2].
Is sermorelin licensed in the UK?
No. It is not a licensed medicine in the UK. Research-grade material is for laboratory research only.
What should a sermorelin COA show?
HPLC purity, mass spectrometry identity, batch number and ideally data on oxidised and truncated impurities.
Related research pages
- Growth-hormone peptides research hub
- Sermorelin vs tesamorelin: a structural comparison
- Research-grade peptides guide
- How to read a peptide certificate of analysis
UK research cluster hubs
References
- Thorner MO, et al. Human pancreatic growth-hormone-releasing factor selectively stimulates growth-hormone secretion in man. Lancet 1983;1(8314-5):24–28. PubMed 6129370
- Frohman LA, et al. Dipeptidylpeptidase IV and trypsin-like enzymatic degradation of human growth hormone-releasing hormone in plasma. J Clin Invest 1989;83:1533–1540. PubMed 2565342
- Prakash A, Goa KL. Sermorelin: a review of its use in the diagnosis and treatment of children with idiopathic growth hormone deficiency. BioDrugs 1999;12:139–157. PubMed 18031173
- Corpas E, Harman SM, Blackman MR. Human growth hormone and human aging. Endocr Rev 1993;14:20–39. PubMed 8491152
- Walker RF. Sermorelin: a better approach to management of adult-onset growth hormone insufficiency? Clin Interv Aging 2006;1:307–308. PubMed 18046908
Reference titles are reproduced as published. Their inclusion documents the literature and does not imply that any product is suitable for, or approved for, use in people.
For laboratory research use only. Sermorelin sold by Peptides Lab UK is supplied strictly for in vitro laboratory research. It is not for human or veterinary use, and nothing on this page is medical advice or guidance on administration. UK purchasers are responsible for complying with all applicable legislation.
