Research area

Growth hormone axis peptides

Growth hormone axis peptides act on the growth hormone-releasing hormone (GHRH) receptor or on the ghrelin receptor (GHS-R1a), or are growth-factor and hormone fragments related to this axis.

Two receptor families dominate this area. GHRH analogues (sermorelin, tesamorelin, CJC-1295) are 29 to 44 residues long and act on the GHRH receptor. Growth hormone secretagogue peptides (ipamorelin, GHRP-2, GHRP-6, hexarelin) are short, five to six residues, built from D-amino acids and unnatural residues, and act on the ghrelin receptor.

The area also includes IGF-1 LR3, a long insulin-like growth factor analogue used in cell culture, and AOD9604, a modified fragment of human growth hormone. The anti-doping and forensic literature provides published LC-MS methods for several members, which makes them useful references when testing a batch.

Compounds in this group

Compound	Type	Formula	Average mass (g/mol)	Listings
AOD9604	Peptide	C₇₈H₁₂₃N₂₃O₂₃S₂	1815.08	2
CJC-1295	Peptide	C₁₆₅H₂₆₉N₄₇O₄₆	3647.19	6
GHRP-2	Peptide	C₄₅H₅₅N₉O₆	817.97	3
GHRP-6	Peptide	C₄₆H₅₆N₁₂O₆	873.01	3
Hexarelin	Peptide	C₄₇H₅₈N₁₂O₆	887.04	2
IGF-1 LR3	Protein (83 residues)	C₄₀₀H₆₁₉N₁₁₁O₁₁₅S₉	9111.45	2
Ipamorelin	Peptide	C₃₈H₄₉N₉O₅	711.85	5
Sermorelin	Peptide	C₁₄₉H₂₄₆N₄₄O₄₂S	3357.88	3
Tesamorelin	Peptide	C₂₂₁H₃₆₆N₇₂O₆₇S	5135.78	4

Analytical points for this group

GHRH-type peptides contain methionine and asparagine; look for +15.995 Da (oxidation) and +0.984 Da (deamidation) variants.
The short secretagogue peptides are small enough to be seen as singly charged ions, so [M+H]+ is usually enough to confirm identity.
D-amino acids have the same mass as L-amino acids; stereochemical purity needs chiral or specially developed chromatographic methods.
IGF-1 LR3 has three disulfide bonds; misfolded isoforms share its mass but not its retention time.

Guides

GuideCommon Peptide Degradation Products and the Mass Shifts That Reveal Them

Oxidation, deamidation, disulfide changes, pyroglutamate formation and adducts each leave a characteristic mass difference. Learn the numbers and…

GuideMass Spectrometry for Peptide Identity: A Practical Guide

How expected mass, observed ions, charge states, adducts, and deconvolution support peptide identity without being confused with purity.

ExplainerPeptide Purity vs Vial Content: Why the Numbers Differ

Why a high HPLC area percentage does not establish peptide quantity, net vial mass, identity, water content, or counterion content.

Frequently asked questions

Which compounds are in the growth hormone axis peptides group?

AOD9604, CJC-1295, GHRP-2, GHRP-6, Hexarelin, IGF-1 LR3, Ipamorelin, Sermorelin, Tesamorelin.

How should a batch of a growth hormone axis peptides compound be checked?

GHRH-type peptides contain methionine and asparagine; look for +15.995 Da (oxidation) and +0.984 Da (deamidation) variants. The short secretagogue peptides are small enough to be seen as singly charged ions, so [M+H]+ is usually enough to confirm identity.

Other research areas

All compound references →