GHRH analogues: sermorelin, CJC-1295 and tesamorelin compared

The family at a glance

• Sermorelin: GHRH(1-29)-NH2, the unmodified active fragment: YADAIFTNSYRKVLGQLSARKLLQDIMSR-NH2.
• Modified GRF(1-29), sold as 'CJC-1295 no DAC': GHRH(1-29) with four substitutions (D-Ala2, Gln8, Ala15, Leu27) to reduce cleavage and oxidation.
• CJC-1295 with DAC: modified GRF(1-29) plus a C-terminal lysine carrying a maleimidopropionyl 'drug affinity complex' that binds covalently to albumin.
• Tesamorelin: full-length GHRH(1-44)-NH2 with a trans-3-hexenoyl group on the N-terminus.

PubChem data

• Sermorelin: C149H246N44O42S, 3357.9 g/mol.
• Tesamorelin: C221H366N72O67S, 5136 g/mol.

Source: PubChem CID 16132413: Sermorelin; PubChem CID 16137828: Tesamorelin

Why the modifications

Position 2 of GHRH is the cleavage site for dipeptidyl peptidase-4; a D-amino acid there slows breakdown. Methionine 27 is oxidation-prone, so leucine replaces it in modified GRF. The DAC group was designed so the peptide binds albumin, and a 2006 study reported prolonged GH and IGF-I elevation after CJC-1295 in that research setting. Tesamorelin's N-terminal acyl group serves the same anti-degradation purpose on the full-length sequence.

Source: Prolonged stimulation of GH and IGF-I secretion by CJC-1295, J Clin Endocrinol Metab 2006 (PubMed 16352683); Tesamorelin, Nat Rev Drug Discov 2011 (PubMed 21283099)

Analytical detection

Because these analogues differ from native GHRH by a few residues, LC-MS/MS methods target unique fragment ions; a 2021 validation study describes detection of several GHRH synthetic analogues together. For a research CoA, the measured mass is the main identity check: modified GRF(1-29) and sermorelin differ by the mass of their four substitutions.

Source: Advances in the detection of GHRH synthetic analogs, Drug Test Anal 2021 (PubMed 34665524)

At Sable

Sable lists these compounds as lyophilised research materials. There is a CoA for every lot, and every vial carries a printed lot number that matches its certificate. A CoA is emailed within 2 hours of a request.

Frequently asked questions