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Molecular Background And Naming — Complete Guide

By Editorial Desk · published 2026-03-23 · last reviewed 2026-05-01 · Blog

Everything below concerns GHRH analogue. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.

Updated 2026-05-01. Numbers and descriptions here follow the published literature rather than marketing material.

Molecular Background and Naming

CJC-1295 is a synthetic peptide designed as a long-acting analogue of growth hormone-releasing hormone (GHRH). Its structure derives from the first 29 amino acids of native GHRH, a fragment often called GRF(1-29). Four substitutions were introduced to slow enzymatic breakdown and extend activity relative to the natural sequence. The compound was developed by ConjuChem as part of a broader effort to improve the pharmacokinetic profile of peptide hormones. It is studied in laboratory and clinical research settings rather than appearing as a naturally occurring substance.

Two related forms circulate in technical discussion under the same family name. The original version carries a drug affinity complex (DAC) that binds covalently to serum albumin after administration, and this linkage substantially extends circulation time. A second form, frequently written as modified GRF(1-29) or CJC-1295 without DAC, lacks that linker and clears much faster. The naming is a frequent source of confusion because the shorthand CJC-1295 can refer to either form depending on the source. Reports sometimes fail to specify which variant was studied.

The peptide backbone includes a D-alanine at position two, which resists cleavage by dipeptidyl peptidase IV, and several other substitutions that reduce degradation. Its molecular weight is roughly 3.4 kDa without the linker and about 3.6 kDa with it. The molecule is water soluble and is normally supplied as a lyophilized powder. Precise sequence and mass values depend on which variant is described, so technical documents usually state the exact form being referenced.

Background and Receptor Mechanism

CJC-1295 is a synthetic peptide belonging to the growth hormone-releasing hormone analog family. It comprises twenty-nine amino acid residues derived from the N-terminal region of natural GHRH. The molecule incorporates several non-natural substitutions that increase resistance to enzymatic degradation. These modifications extend its activity compared with the native hormone fragment. Researchers use it to study pituitary growth hormone secretion in laboratory and clinical settings. This compound is distinct from native GHRH in its stability profile.

Two principal forms appear in the literature and in research supply. One carries a drug affinity complex, a maleimide-based group that forms a covalent bond with circulating albumin. This linkage slows clearance and produces a long-lasting elevation of peptide levels. The other form lacks that group and is often labeled MOD GRF(1-29). It has a much shorter circulation time. Both variants retain the same core receptor-binding sequence. Reported half-lives differ substantially between the two.

Cjc-1295 at a glance

PropertyValueNotes
Molecular weight (no linker)~3.37 kDaCalculated from peptide sequence
Molecular weight (with linker)~3.65 kDaIncludes albumin-binding moiety
AppearanceWhite to off-white powderTypically lyophilized
SolubilitySoluble in waterAlso dissolves in aqueous buffers
Common synonymsModified GRF(1-29), DAC:GRFUsage varies by source

Structure And Receptor Pharmacology

CJC-1295 belongs to a class of synthetic peptides modeled on growth hormone releasing hormone, a forty-four amino acid signal produced by the hypothalamus. The compound is built from the first twenty-nine residues of the natural sequence, with four substitutions introduced at positions 2, 8, 15 and 27. These changes were designed to slow enzymatic breakdown while preserving receptor activation. The result is a peptide that is shorter than native GHRH and considerably more resistant to ordinary clearance pathways in circulation.

Two related forms appear under the CJC-1295 name. The simpler analogue, commonly written as modified GRF(1-29), carries the four substitutions but no additional conjugation. The second form attaches a maleimidopropionic acid linker to a lysine residue, a modification frequently called the drug affinity complex. That linker reacts with the free thiol on serum albumin to form a covalent bond. Because albumin has a long residence time in blood, the conjugated peptide stays in circulation far longer than the unconjugated analogue.

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Background and Molecular Design

CJC-1295 belongs to a family of synthetic peptides modeled on growth hormone-releasing hormone, the hypothalamic signal that prompts the pituitary to release growth hormone. The compound is built from the first twenty-nine amino acids of the natural human sequence, a fragment that retains full receptor binding capacity. Native growth hormone-releasing hormone is degraded quickly in circulation, so the fragment alone has limited practical value. Early work therefore focused on chemical modifications that preserve receptor binding while slowing enzymatic breakdown. The result is a molecule described in the literature as a long-acting analog of the natural hormone.

CJC-1295 Structure And Mechanism

The drug affinity complex is a maleimidopropionic acid group attached to a lysine side chain. It reacts with the free thiol of cysteine-34 on circulating albumin, forming a covalent bond. This conjugation keeps the peptide in the bloodstream and shields it from rapid renal filtration and proteolysis. Reported circulation half-lives for the albumin-bound form fall in the range of roughly six to nine days in early human studies.

Binding to GHRH receptors on pituitary somatotroph cells triggers cyclic AMP signaling and stimulates growth hormone synthesis and release. Because the peptide acts upstream of the pituitary, effects are mediated through endogenous growth hormone rather than direct receptor activation in peripheral tissues. Increases in insulin-like growth factor 1 are generally described as a downstream consequence. Most published human exposure data come from small early-stage studies, and the clinical significance of the pharmacokinetic profile remains incompletely characterized.

Notes from published material

== Interactions == Elevated concentrations of eluxadoline were observed with co-administration of inhibitors of the transporter protein OATP1B1, such as ciclosporin, gemfibrozil, certain antiretrovirals, rifampicin, and eltrombopag. Concurrent use of other drugs that cause constipation, such as opioids, alosetron, anticholinergics, and bismuth subsalicylate, is not preferred. Eluxadoline increases the concentrations of drugs which are OATP1B1 and BCRP substrates. Co-administration of eluxadoline with rosuvastatin may increase the risk of rhabdomyolysis.

Many drug interactions are due to alterations in drug metabolism. Further, human drug-metabolizing enzymes are typically activated through the engagement of nuclear receptors. One notable system involved in metabolic drug interactions is the enzyme system comprising the cytochrome P450 oxidases.

Hemoglobin D – (α2βD2) – A variant form of hemoglobin. Hemoglobin H (β4) – A variant form of hemoglobin, formed by a tetramer of β chains, which may be present in variants of α thalassemia. Hemoglobin Barts (γ4) – A variant form of hemoglobin, formed by a tetramer of γ chains, which may be present in variants of α thalassemia. Hemoglobin S (α2βS2) – A variant form of hemoglobin found in people with sickle cell disease. There is a variation in the β-chain gene, causing a change in the properties of hemoglobin, which results in sickling of red blood cells. Hemoglobin C (α2βC2) – Another variant due to a variation in the β-chain gene. This variant causes a mild chronic hemolytic anemia. Hemoglobin E (α2βE2) – Another variant due to a variation in the β-chain gene. This variant causes a mild chronic hemolytic anemia. Hemoglobin AS – A heterozygous form causing sickle cell trait with one adult gene and one sickle cell disease gene Hemoglobin SC disease – A compound heterozygous form with one sickle gene and another encoding hemoglobin C. Hemoglobin Hopkins-2 – A variant form of hemoglobin that is sometimes viewed in combination with hemoglobin S to produce sickle cell disease.

Sources: en.wikipedia.org

Background from the literature

Aspartic acid, for example, possesses one protonated amine and two deprotonated carboxyl groups, for a net charge of −1 at physiological pH. Fatty acids and fatty acid derivatives are another group of carboxylic acids that play a significant role in biology. These contain long hydrocarbon chains and a carboxylic acid group on one end. The cell membrane of nearly all organisms is primarily made up of a phospholipid bilayer, a micelle of hydrophobic fatty acid esters with polar, hydrophilic phosphate "head" groups. Membranes contain additional components, some of which can participate in acid–base reactions. In humans and many other animals, hydrochloric acid is a part of the gastric acid secreted within the stomach to help hydrolyze proteins and polysaccharides, as well as converting the inactive pro-enzyme, pepsinogen into the enzyme, pepsin. Some organisms produce acids for defense; for example, ants produce formic acid. Acid–base equilibrium plays a critical role in regulating mammalian breathing. Oxygen gas (O2) drives cellular respiration, the process by which animals release the chemical potential energy stored in food, producing carbon dioxide (CO2) as a byproduct. Oxygen and carbon dioxide are exchanged in the lungs, and the body responds to changing energy demands by adjusting the rate of ventilation. For example, during periods of exertion the body rapidly breaks down stored carbohydrates and fat, releasing CO2 into the blood stream. In aqueous solutions such as blood CO2 exists in equilibrium with carbonic acid and bicarbonate ion.

The Desert Rats also destroyed multiple Iraqi artillery positions. The division also took over 7,000 Iraqi prisoners of war including two division commanders and two other general officers. The British 1st Armoured Division destroyed or isolated four Iraqi infantry divisions (the 26th, 48th, 31st, and 25th) and overran the Iraqi 52nd Armored Division in several sharp engagements. The Iraqi 80th Armored Brigade would also fall victim to the British 1st Armoured Division. Iraq was represented mostly by its own VII Corps and its Jihad Corps. Its most notable participants were its elite Republican Guard Divisions Tawakalna, Medina, Hammurabi, and Adnan. The first three of these had a strength of over 660 tanks, 660 infantry fighting vehicles, and thousands of antitank weapons, self propelled artillery, and other combat systems. The Tawakalna Republican Guard Division was Iraq's most powerful division which included approximately 14,000 soldiers, 220 T-72 tanks, 284 infantry fighting vehicles, 126 artillery pieces, and 18 MLRS. The Iraqi 52nd Armored Division was also a primary participant. It was a powerful division consisting of 245 tanks and 195 armored fighting vehicles. The Iraqi 10th and 12th Armored Divisions were also present. The two divisions formed the foundation of the Jihad Corps. The Iraqi 10th Armored Division was considered the best regular division in the Iraqi Army. It had more modern equipment than the other regular Iraqi units. It was equipped with T-72 and T-62 tanks. The T-62 tank being its primary system.

A single-domain antibody (sdAb), also known as a Nanobody, is an antibody fragment consisting of a single monomeric variable antibody domain. Like a whole antibody, it is able to bind selectively to a specific antigen. With a molecular weight of only 12–15 kDa, single-domain antibodies (sdAbs) are much smaller than common antibodies (150–160 kDa) which are composed of two heavy protein chains and two light chains, and even smaller than Fab fragments (~50 kDa, one light chain and half a heavy chain) and single-chain variable fragments (~25 kDa, two variable domains, one from a light and one from a heavy chain). The first single-domain antibodies were engineered from heavy-chain antibodies found in camelids at the Université Libre de Bruxelles; these are called VHH fragments. Cartilaginous fish also have heavy-chain antibodies (IgNAR, 'immunoglobulin new antigen receptor'), from which single-domain antibodies called VNAR fragments can be obtained. An alternative approach is to split the dimeric variable domains from common immunoglobulin G (IgG) from humans or mice into monomers. Although most research into single-domain antibodies is currently based on heavy chain variable domains, nanobodies derived from light chains have also been shown to bind specifically to target epitopes. Camelid nanobodies have been shown to be just as specific as antibodies, and in some cases they are more robust. They are easily isolated using the same phage panning procedure used for antibodies, allowing them to be cultured in vitro in large concentrations.

Sources: en.wikipedia.org

Frequently asked questions

Is CJC-1295 a natural hormone?

No. It is a synthetic analogue modeled on the first 29 residues of human GHRH. The substitutions and any linker are laboratory modifications rather than features of the endogenous peptide.

Why do two versions share one name?

Early development used the albumin-binding form, and a shorter variant was later discussed under the same label. Because the two differ in half-life and handling, ambiguity arises whenever a source omits the variant designation.

What is the relationship to GRF(1-29)?

The compound derives from that fragment but is not identical to it. The parent fragment lacks the stabilizing substitutions, so its degradation rate and duration of action differ noticeably.

What is CJC-1295?

It is a synthetic peptide modeled on growth hormone-releasing hormone. The molecule is used in research on pituitary growth hormone secretion. It differs from the natural hormone through several stabilizing substitutions.

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