Sermorelin is the N-terminal 29-residue fragment of growth hormone-releasing hormone, prepared as the C-terminal amide. It is catalogued interchangeably as GRF (1–29) amide, and that name is the more informative of the two because it states exactly what the molecule is.
| CAS Registry Number | 86168-78-7 |
|---|---|
| Molecular formula | C149H246N44O42S |
| Average molecular weight | 3357.9 g/mol |
| Also known as | GRF (1-29) amide, GHRH (1-29) amide |
| Class | GHRH fragment analogue |
| Classification | Ligand at the GHRH receptor, a class B GPCR |
| Physical form | Lyophilised powder, sealed glass vial |
| Storage | 2–8 °C, protected from light |
| Catalogue reference | CA-15 |
Identity and classification
Native GHRH is 44 residues. Sermorelin is its first 29, amidated at the C-terminus. The truncation reflects a structure–activity finding that the receptor-binding determinants of GHRH reside in the N-terminal region; the residues beyond 29 are not required for receptor recognition. That is a statement about structure–activity relationships, not about any outcome.
Structure
Residues 1–29 of human GHRH: YADAIFTNSYRKVLGQLSARKLLQDIMSR, terminating in a primary carboxamide rather than a free acid.
Three points of structure worth separating:
- The C-terminal amide is the defining modification. GRF(1–29) free acid and GRF(1–29) amide are different compounds. Amidation removes the terminal negative charge and is not a trivial synthetic detail.
- All-L, all proteinogenic. Unlike CJC-1295, sermorelin carries no substituted or non-natural residues. It is the unmodified native fragment.
- Single methionine at position 27 — the sulfur in the formula. No cysteine, no disulfide.
The GHRH comparison set
Sermorelin is the reference point against which the other two GHRH-family compounds here are best understood:
| Sermorelin | GRF(1–29) amide. No protective modification at the N-terminus — the DPP-4 cleavage site between residues 2 and 3 is intact. |
|---|---|
| CJC-1295 | The same 29-residue backbone with four substitutions: Ala2→D-Ala, Asn8→Gln, Gly15→Ala, Met27→Leu. The D-Ala addresses the cleavage site; the Met→Leu substitution also removes the oxidation liability. |
| Tesamorelin | Full-length GRF(1–44) amide with an N-terminal hexenoyl group — blocking the same site by acylation rather than by substitution. |
Reading the three side by side, the Met27→Leu substitution in CJC-1295 is worth noting for a practical reason: it means CJC-1295 has no methionine to oxidise, while sermorelin and tesamorelin both do.
Specification and characterisation
- RP-HPLC purity at 214 nm; 280 nm is informative via the two tyrosines and the phenylalanine.
- Mass confirmation against 3357.9 average.
- Methionine oxidation. Met27 gives a +16 Da sulfoxide. Because CJC-1295 lacks this residue, oxidation is a differentiating stability characteristic between the two compounds rather than a generic caution.
- Amidation completeness. The free-acid form differs by +1 Da — the same low-resolution problem described for the melanocortin pair. High-resolution MS or a chromatographic comparison is required to confirm amidation.
- Deletion sequences across a 29-residue synthesis.
- Net peptide content and counter-ion. Commonly supplied as the acetate, which carries its own registry number.
Handling and stability
Store sealed at 2–8 °C, dry, protected from light, and equilibrate in a desiccator before opening. Minimise oxygen exposure because of Met27.
Reference catalogues do not recommend storing aqueous solutions of this peptide beyond one day.
Related compounds in this library
CJC-1295 and tesamorelin, as compared above. Ipamorelin is sometimes grouped alongside these but acts at a different receptor family entirely — it is a growth hormone secretagogue receptor ligand, not a GHRH receptor ligand, and shares no sequence with any of them.
References
Chemical, specification and analytical sources. This list is deliberately limited to chemistry and analytical references.
- Cayman Chemical, sermorelin record — formula, molecular weight, sequence
- Sigma-Aldrich, GRF (1-29) amide human — specification and registry data
- ChemicalBook, CAS 86168-78-7 — independent formula confirmation
- Bachem, Handling and Storage Guidelines for Peptides — methionine oxidation, solution stability
Available from the catalogue
Sermorelin 10 mg — 10 mg of lyophilised powder in a sealed glass vial, supplied with a lot-matched certificate of analysis. Bulk pricing applies from five vials.
Cosmic Aminos supplies this material as a laboratory reagent for in-vitro research use only. It is not a drug, food, cosmetic or dietary supplement, is not approved by the Food and Drug Administration for any use, and is not for human or veterinary consumption. No dosing, administration or preparation guidance is provided.