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Background And Molecular Features — Practical Notes

By Editorial Desk · published 2026-04-19 · last reviewed 2026-05-03 · News

CJC-1295 comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.

Updated 2026-05-03. Numbers and descriptions here follow the published literature rather than marketing material.

Background and Molecular Features

Two related peptides circulate under the CJC-1295 label, and they differ mainly in how long they persist in circulation. The version carrying a drug affinity complex includes a maleimidopropionic acid linker that forms a covalent bond with serum albumin. The other version, usually written as modified GRF(1-29) or tetrasubstituted GRF(1-29), lacks that linker and is cleared quickly. Mixing the two produces inconsistent readings of published half-life values, because the linker rather than the receptor-facing sequence drives most of the difference.

The core sequence keeps the receptor-binding region of GHRH while replacing four positions that are vulnerable to dipeptidyl peptidase-4 and other proteases. Substitutions at positions 2, 8, 15, and 27 raise metabolic stability relative to the natural hormone. The N-terminal residues remain essential for activity, so changes there generally lower potency. Molecular weight sits near 3368 daltons for the tetrasubstituted analog without the linker, while the albumin-binding form is heavier because of the added maleimide group.

Structure And Receptor Pharmacology

Receptor level activity follows the canonical GHRH pathway. The peptide binds the GHRH receptor, a class B G protein coupled receptor on somatotroph cells of the anterior pituitary. Binding raises intracellular cyclic AMP, which promotes calcium entry and the release of growth hormone into the bloodstream. Because the molecule acts at the same receptor as the endogenous hormone, its effect is superimposed on the natural pulsatile rhythm rather than replacing it. Whether sustained receptor occupation leads to desensitization is not fully settled.

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.

Cjc-1295 at a glance

PropertyValueNotes
ClassSynthetic peptideGHRH receptor agonist
Sequence length29 amino acidsDerived from human GHRH
Molecular weightAbout 3368 Da without linkerAlbumin-binding form is heavier
AppearanceWhite to off-white lyophilized powderCommon form for research reference material
Typical storage-20 °C or below, desiccatedProtect powder from light and moisture

Analytical Characterization and Storage

Verification matters because research peptides vary widely in quality. A certificate of analysis is only as reliable as the method behind it, and a single chromatographic trace reveals little about counter-ions, residual solvents, or water content. Independent laboratories commonly pair mass confirmation with chromatographic purity and, where relevant, quantify water along with acetate or trifluoroacetate content. Reported purity figures are not standardized across suppliers, so a stated value such as ninety-eight percent is not directly comparable unless the analytical method, column, and detection wavelength accompany it.

Characterization of this peptide relies on a small set of routine techniques. Reversed-phase high-performance liquid chromatography separates the target from truncated or oxidized by-products and yields a purity estimate when paired with ultraviolet detection near 214 nanometers. Mass spectrometry, either electrospray coupled to liquid chromatography or matrix-assisted laser desorption, confirms that the observed mass matches the value calculated for the expected sequence. Amino acid analysis, and enzymatic digestion followed by fragment mapping, are used when the sequence itself rather than the mass requires verification.

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Background and Molecular Design

Two forms circulate under the CJC-1295 name, and they differ by a single appended group. The version without a drug affinity complex carries four substitutions along the peptide chain, including a D-alanine near the amino terminus and replacements at three other positions. These changes block the enzyme dipeptidyl peptidase IV and remove a methionine residue that is prone to oxidation. The modified fragment is frequently labeled MOD GRF 1-29. Naming conventions are inconsistent across informal sources, which is a common source of confusion.

The second form adds a maleimide-bearing linker to the lysine at the carboxyl end. This group reacts with cysteine-34 on circulating serum albumin, forming a covalent bond that keeps the peptide in the bloodstream for far longer. ConjuChem developed the molecule as a way to extend the action of a peptide without frequent administration. The albumin attachment is the defining structural feature of the drug affinity complex version. Whether continuous exposure produces effects distinct from shorter pulses remains an unresolved research question.

Compound Identity and Development History

Two forms circulate in research settings and are frequently confused. One carries the drug affinity complex and is often written as CJC-1295 with DAC; the other lacks that group and is usually called modified GRF(1-29). The two share the same core sequence but differ sharply in how long they persist in blood. Products labelled only as CJC-1295 normally refer to the version carrying the complex. Documentation that omits the distinction leaves the intended molecule ambiguous.

CJC-1295 is a synthetic peptide built as a long-acting analogue of growth hormone-releasing hormone. Its backbone matches the first twenty-nine residues of the natural human hormone, with four amino acid substitutions added to slow enzymatic breakdown. A reactive maleimide group, commonly termed the drug affinity complex, allows the peptide to attach to circulating albumin after administration. That albumin attachment keeps the molecule in the bloodstream for an extended period instead of being cleared within minutes.

The compound emerged from work at a Canadian biotechnology firm in the early 2000s. Early human studies examined its effect on growth hormone and insulin-like growth factor 1 in healthy volunteers and in people with HIV-associated fat redistribution. Reports described sustained increases in both markers after a single injection. Development did not advance to regulatory approval, and the clinical programme was later discontinued. The molecule is now encountered mainly as a research chemical rather than a marketed medicine.

Reference notes

Fyodor Dostoevsky's book The Idiot had a character, General Ivolgin, who witnessed and recounted his relationship with Napoleon during the Campaign of Russia. Roger Brook is a fictional secret agent and Napoleonic Wars Era gallant, later identified as the Chevalier de Breuc, in a series of twelve novels by Dennis Wheatley. The Hornblower books by C.S. Forester follow the naval career of Horatio Hornblower during the Napoleonic Wars. The 1951 film "Captain Horatio Hornblower" starring Gregory Peck and Virginia Mayo and directed by Raoul Walsh is a film adaption based on Forester's series of novels. Also by C.S. Forester two novels of the Peninsular War in Spain and Portugal: "Death to the French" (1932, published in the United States under the title "Rifleman Dodd"), and "The Gun" (1933), later made into a 1957 film, "The Pride and the Passion", with Cary Grant, Frank Sinatra, Sophia Loren, directed by Stanley Kramer. R. F. Delderfield, two novels about the Napoleonic Wars; Seven Men of Gascony (1949) about seven French infantrymen serving in a succession of Napoleonic campaigns, and Too Few For Drums (1964) about British soldiers cut off behind the French lines in Portugal in 1810, during the Peninsular War. The Aubrey–Maturin series of novels is a sequence of 20 historical novels by Patrick O'Brian portraying the rise of Jack Aubrey from Lieutenant to Rear Admiral during the Napoleonic Wars. The film Master and Commander: The Far Side of the World starring Russell Crowe and directed by Peter Weir is based on this series of books.

Cardiomyoplasty is a surgical procedure in which healthy muscle from another part of the body is wrapped around the heart to provide support for the failing heart. Most often the latissimus dorsi muscle is used for this purpose. A special pacemaker is implanted to make the skeletal muscle contract. If cardiomyoplasty is successful and increased cardiac output is achieved, it usually acts as a bridging therapy, giving time for damaged myocardium to be treated in other ways, such as remodeling by cellular therapies.

== Effect on investment, sales and profit == According to Thomson Reuters in their 2012 publication "The Economic Power of Orphan Drugs", there has been increased investment in orphan drug research and development, partly due to the U.S. Orphan Drug Act of 1983 (ODA) and similar acts in other regions of the world driven by "high-profile philanthropic funding". According to a 2012 article in Drug Discovery Today, the years 2001 to 2011 were the "most productive period in the history of orphan drug development, in terms of average annual orphan drug designations and orphan drug approvals". For the same decade the compound annual growth rate (CAGR) of the orphan drugs was an "impressive 25.8%, compared to only 20.1% for a matched control group of non-orphan drugs". By 2012, the market for orphan drugs was worth US$637 million, compared with US$638 million for a control group of non-orphan drugs. By 2012,

=== Research parks and commercialization === Tech Parks Arizona is the research park of the University of Arizona. It comprises three primary facilities: the UA Tech Park at Rita Road, the UA Tech Park at The Bridges, and the University of Arizona Center for Innovation (UACI).

=== Role of norepinephrine transporter (NET) === Approximately 90% of released NE from the sympathetic nerve fibers is taken up again by postganglionic adrenergic neurons through the protein NET. The reuptake of NE is either repackaged into vesicles or degraded by the enzyme monoamine oxidase (MAO). The NET is located in the plasma membrane of noradrenergic neurons and serves as the fundamental mechanism by terminating the biological effects of NE in the synapse. The NE inactivation process, when taken up by the NET, is crucial in preventing too much increase in the NE concentration in the synaptic cleft. The reuptake of NE is competitive with various naturally occurring amines and drugs.

Sources: en.wikipedia.org

Reference notes

==== White Americans ==== As of 2018, 41.3% of white American men over the age of 20 are obese, while 39% of white women in this age cohort are obese. However, newer data from 2025 suggests that the actual obesity rate for White Americans is around 65%, based on anthropometric measurements alone rather than BMI. This newer study did not segregate Hispanics as a race and includes people identifying as both "White" and "Hispanic".

==== The storage iron pool ==== Iron can be stored in ferritin as ferric iron due to the ferroxidase activity of the ferritin heavy chain. Dysfunctional ferritin may accumulate as hemosiderin, which can be problematic in cases of iron overload. The ferritin storage iron pool is much larger than the labile iron pool, ranging in concentration from 0.7 mM to 3.6 mM.

=== Obesity === It is well known that children, adolescents, or adults with OSA are often obese. People with obesity show an increase in neck fat tissue, which potentiates respiratory obstruction during sleep. However, people of all ages and sexes with normal body mass indices (BMIs) can also demonstrate OSA – and these people do not have significant measures of subdermal or intra-neck fat as shown on DEXA scans. It is speculated that they may have increased muscle mass or a tendency toward decreased muscle tone, potentiating airway collapse during sleep. However, loss of muscle tone is a key feature of deep sleep, and whilst obesity seems a common association, it is not an invariable state of OSA. Sleeping supine (on one's back) is also represented as a risk factor for OSA. Gravity and loss of tongue and throat tone as a person enters deep sleep are clear factors contributing to OSA development. But this explanation is also confounded by the presence of neck obesity. The use of CPAP primarily expands a collapsed upper airway, allowing for nasal breathing. A positive response to CPAP confirms that airway collapse is the cause of OSA. Throat lesions, particularly enlarged tonsils, are well recognized as aggravators of OSA, and removal may provide full, partial, or semi-permanent relief from OSA, which also indicates that enlarged tonsils may play a role in the pathogenesis of OSA.

=== Non-medical use === Though not an approved drug, LGD-4033 (Ligandrol) has been sold on the black market as a designer drug in countries where it is classified as an illegal substance. Along with enobosarm (ostarine; GTx-024, S-22), andarine (GTx-007; S-4), and vosilasarm (RAD140; "testolone"), LGD-4033 is one of the most popular and common non-medically-used SARMs. Many products sold online that are purported to be LGD-4033 either contain none or contain other unrelated substances, and doses are also frequently not as labeled. Social media has played an important role in facilitating the widespread non-medical use of SARMs. On 23 October 2017, a nutritional supplement company in Missouri called Infantry Labs was warned by the FDA that the distribution of two of its products violated the Federal Food, Drug, and Cosmetic Act. One of the substances was LGD-4033. The company advertised as benefits of the LGD-4033: "increases in lean body mass and decrease in body fat" and "increases in strength, well being, as well as healing possibilities". The company mislabeled as "dietary supplements" what should have been "new drugs" or "prescription drugs" and were instructed to document the steps they would take in order to cease the violation. Also on 23 October 2017, the FDA sent a warning letter to a New Jersey company called Panther Sports Nutrition. The company's marketing approach for the product was similar to that of the Infantry Labs case, and the product was advertised as a "mass builder" and "physique enhancing agent".

Bremelanotide, sold under the brand name Vyleesi, is a medication used to treat low sexual desire in women. Specifically, it is used for low sexual desire which occurs before menopause and is not due to medical problems, psychiatric problems, or problems within the relationship. It is given by an injection just under the skin of the thigh or abdomen. Common side effects include nausea, pain at the site of injection, and headache. It may also cause a temporary increase in blood pressure and decrease in heart rate after each dose, and darkening of the gums, face, and breasts. The medication is a peptide and acts by activating the melanocortin receptors. Bremelanotide was approved for medical use in the United States in 2019. It was developed by Palatin Technologies.

Sources: en.wikipedia.org

Frequently asked questions

What is the difference between CJC-1295 and natural GHRH?

Natural GHRH is degraded quickly by dipeptidyl peptidase-4 and related enzymes, giving it a half-life measured in minutes. CJC-1295 carries substitutions that slow that breakdown, so it stays intact longer. Both act at the same pituitary receptor and produce the same class of signal.

Why does one name cover two different peptides?

The label was first attached to the albumin-binding form during early development work. A shorter analog without the linker later became known by the same name in informal use. Published papers normally state which version was studied, so the methods section resolves the ambiguity.

Is CJC-1295 a steroid or a natural hormone?

It is a synthetic peptide rather than a steroid, and it does not occur naturally in the body. Its sequence is derived from a hypothalamic hormone called growth hormone-releasing hormone. It works as a receptor agonist rather than as a replacement for that hormone.

Is CJC-1295 the same as modified GRF(1-29)?

The names are often used interchangeably in casual writing, but they are not strictly identical. Modified GRF(1-29) refers to the unconjugated analogue carrying only the four substitutions. The version sold as CJC-1295 with DAC includes the albumin binding linker and clears much more slowly.

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