Compound comparison · 7 min read

GHRH Analogs Compared: Sermorelin, Tesamorelin and CJC-1295 (no DAC)

Three synthetic analogs of growth hormone-releasing hormone compared on length, sequence changes, molecular weight and CAS number, plus how ipamorelin differs from all three.

Sermorelin, tesamorelin and CJC-1295 are all built on the sequence of growth hormone-releasing hormone (GHRH), a 44-residue peptide. They differ in how much of that sequence they keep and how it has been modified. This guide lays out the chemistry side by side.

At a glance

	Sermorelin	CJC-1295 (no DAC)	Tesamorelin
Length	29 residues	29 residues	44 residues
Based on	GHRH(1-29)-NH2, unmodified	GHRH(1-29)-NH2 with 4 substitutions	GHRH(1-44)-NH2 with an N-terminal acyl group
Modification	None (C-terminal amide)	D-Ala2, Gln8, Ala15, Leu27	trans-3-hexenoyl on Tyr1
Molecular weight	3357.9 g/mol	3367.9 g/mol	5135.8 g/mol
CAS number	86168-78-7	863288-34-0	218949-48-5

Sermorelin: the 1-29 fragment

Early structure-activity work found that the first 29 residues of GHRH carry its receptor activity. Sermorelin is exactly that fragment, GHRH(1-29), with a C-terminal amide. It is the reference point the other two analogs are compared against. See Atlas Sermorelin.

CJC-1295 (no DAC): the 1-29 fragment, stabilized

Also called modified GRF(1-29), this analog keeps sermorelin's length but swaps four residues. The best known change is D-alanine at position 2: the natural L-Ala2 is the site where the enzyme dipeptidyl peptidase-4 (DPP-4) cuts GHRH, and the D-form resists that cleavage. The other substitutions were chosen to reduce rearrangement and oxidation and to improve stability in solution.

"No DAC" distinguishes it from CJC-1295 with DAC, which adds a lysine carrying a reactive maleimide group (the "drug affinity complex") designed to bind albumin. The two are different molecules with different masses, so check the COA. Atlas supplies the no-DAC form, blended 1:1 with ipamorelin; see CJC-1295 (no DAC) / Ipamorelin.

Tesamorelin: the full sequence, acylated

Tesamorelin keeps all 44 residues of GHRH and adds a trans-3-hexenoyl group to the N-terminal tyrosine. That acyl cap serves the same purpose as CJC-1295's D-Ala2: it protects the N-terminus from DPP-4. At about 5.1 kDa it is the largest of the three and the most demanding to synthesize and purify. See Atlas Tesamorelin.

Where ipamorelin fits

Ipamorelin is often paired with these analogs, but it is not a GHRH analog at all. It is a synthetic pentapeptide (Aib-His-D-2Nal-D-Phe-Lys-NH2, 711.9 g/mol) that acts at a different receptor, the ghrelin receptor (GHS-R1a). Its non-standard residues make it resistant to common peptidases.

Confirming identity on a COA

Peptides this size appear as a series of multiply charged ions in electrospray mass spec. Sermorelin and CJC-1295 (no DAC) differ by only about 10 Da, so the deconvoluted mass needs to be reported precisely to tell them apart. For a blend vial, the report should identify both components; see how to read a blend COA.

Compounds in this guide

Signaling Research

Sermorelin

Synthetic GHRH(1-29)-NH2, the shortest fully functional fragment of endogenous GHRH

3357.9 g/mol · CAS 86168-78-7

COA on release

Signaling Research

Tesamorelin

44-residue GHRH analog with an N-terminal trans-3-hexenoyl group

5135.8 g/mol · CAS 218949-48-5

COA on release

Signaling Research

CJC-1295 (no DAC) / Ipamorelin

Two-component research blend, 5 mg of each peptide per vial

3367.9 / 711.9 g/mol · CAS 863288-34-0 / 170851-70-4

COA on release

Signaling Research

Ipamorelin

Synthetic pentapeptide containing non-proteinogenic and D-amino acids

711.9 g/mol · CAS 170851-70-4

COA on release

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