If you have been reading about modified GRF(1-29) and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2025-08-23. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
Lyophilised powder is the usual supplied form. The material is hygroscopic, so vials are typically equilibrated to room temperature before opening in order to prevent condensation on the contents. Long-term storage is generally described at minus twenty degrees Celsius or colder, protected from light and moisture. Repeated freeze-thaw cycles are avoided because they promote aggregation and loss of soluble material. A reconstituted solution is considerably less stable than the dry powder and is normally kept refrigerated for short periods only.
Identity and purity are assessed mainly by reversed-phase high-performance liquid chromatography combined with mass spectrometry. The chromatographic separation resolves the target peptide from truncation products and from species carrying oxidised residues, while mass measurement confirms the expected molecular mass. Because the two common variants differ by roughly 280 daltons, a mass determination distinguishes them unambiguously. Purity is often quoted as a percentage of total peak area, although that figure depends on the detection wavelength and the integration method applied.
Reported half-lives differ widely between the two variants and between species. Values for the albumin-binding form are usually expressed in days, while the unconjugated form is measured in minutes to a few hours. Sampling schedules, assay sensitivity, and route of administration all influence the numbers, which limits direct comparison across studies. Whether sustained receptor occupancy produces different downstream effects from pulsatile stimulation remains an open question in the published work. Claims about relative potency should therefore be read alongside the specific study design that produced them.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C152H252N44O42 | Cited for the form without the drug affinity complex |
| Molecular weight | About 3368 Da | Reported value for modified GRF(1-29) |
| Appearance | White to off-white powder | Lyophilised solid as usually supplied |
| Solubility | Soluble in water and polar solvents | Clarity depends on purity and salt content |
| Typical storage | -20 C or below, dry | Protect from light and repeated warming cycles |
The peptide backbone corresponds to GRF(1-29), the first 29 residues of native growth hormone-releasing hormone, which retains most of the receptor-activating activity of the full-length molecule. Four substitutions distinguish the analog from the natural sequence: D-alanine at position 2, glutamine at position 8, alanine at position 15, and leucine at position 27. These changes slow cleavage by dipeptidyl peptidase IV, the enzyme that degrades native hormone in plasma within minutes. The outcome is improved enzymatic stability combined with a still brief residence time when no additional modification is present.
Naming in this area is inconsistent, and readers should treat product labels with care. In much of the literature and in vendor catalogs, the unqualified term refers to the albumin-binding version, while the version lacking the DAC group appears as modified GRF(1-29), mod GRF(1-29), or the same name with a without-DAC qualifier. Because one abbreviation has been applied to both materials, the only reliable way to identify a sample is to check the stated sequence and the presence of the linker.
CJC-1295 is the name used for a synthetic peptide modeled on growth hormone-releasing hormone, the hypothalamic signal that prompts the pituitary to release growth hormone. The compound was described by a Canadian drug discovery company in the mid-2000s as a long-acting research tool. Two closely related molecules share the name in practice: one carries a drug affinity complex, or DAC, group, and one does not. The distinction matters because the two behave differently in circulation.
CJC-1295 is a synthetic analogue of growth hormone-releasing hormone, built on the 29-amino-acid GHRH(1-29) fragment. Four substitutions distinguish it from the natural sequence: D-alanine at position 2, glutamine at position 8, alanine at position 15, and leucine at position 27. These changes reduce enzymatic cleavage and extend the peptide's persistence in circulation. The compound is discussed in two forms, one carrying a drug affinity complex and one without it.
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.
Lyophilized peptide powder is comparatively stable when kept dry, cold, and protected from light. Once dissolved, the molecule is vulnerable to deamidation, oxidation, and aggregation, with the rate depending on pH, buffer composition, and temperature. Alkaline conditions and repeated freeze-thaw cycles accelerate loss of the intact peptide. The methionine present in the native sequence is a known oxidation site, which is one reason it was replaced in the modified fragment. Suppliers typically recommend cold storage of solutions and use within a short window.
Analytical confirmation usually relies on reversed-phase high-performance liquid chromatography for purity and on liquid chromatography coupled to mass spectrometry for identity. Mass data reveal the expected molecular mass and can flag truncated or oxidized species. Amino acid analysis and peptide mapping provide sequence-level verification. Immunoassays are used in some biological matrices, but antibodies raised against one releasing-hormone analog may cross-react with another. Reported purity figures depend heavily on the method used, so comparisons between suppliers require matching the analytical approach.
The two variants differ dramatically in how long they persist in circulation. The form lacking the albumin-binding group has a plasma half-life measured in tens of minutes, comparable to the natural hormone fragment. The version carrying the drug affinity complex binds albumin and shows a half-life of roughly six to eight days in human studies. That figure comes from small trials that tracked hormone levels over extended periods. The physiological consequences of sustained versus pulsatile stimulation are still debated and the literature does not settle the point.
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Stalin's plans for the city included a network of broad avenues and roadways, some of them more than ten lanes wide, which—while significantly simplifying movement through the city—were constructed at the expense of many historical buildings and districts. Among the many losses from Stalin's demolitions were the Sukharev Tower, an old city landmark, as well as mansions and commercial buildings. The city's new status as the capital of a strongly secular nation made religiously significant buildings particularly vulnerable to demolition. Many of the city's churches—in most cases some of Moscow's oldest and most prominent buildings—were destroyed. Notable examples of this destruction include Kazan Cathedral and the Cathedral of Christ the Saviour. During the 1990s, both cathedrals were rebuilt. Many smaller churches, however, were lost.
Unsepttrium, element 173, may be an even better heavier homologue of ununennium; with a predicted electron configuration of [Usb] 6g1, it returns to the alkali-metal-like situation of having one easily removed electron far above a closed p-shell in energy, and is expected to be even more reactive than caesium.
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An endolith or endolithic is an organism (archaeon, bacterium, fungus, lichen, algae, sponge, or amoeba) that is able to acquire the necessary resources for growth in the inner part of a rock, mineral, coral, animal shells, or in the pores between mineral grains of a rock. Many are extremophiles, living in places long considered inhospitable to life. The distribution, biomass, and diversity of endolith microorganisms are determined by the physical and chemical properties of the rock substrate, including the mineral composition, permeability, the presence of organic compounds, the structure and distribution of pores, water retention capacity, and the pH. Normally, the endoliths colonize the areas within lithic substrates to withstand intense solar radiation, temperature fluctuations, wind, and desiccation. They are of particular interest to astrobiologists, who theorize that endolithic environments on Mars and other planets constitute potential refugia for extraterrestrial microbial communities.
The brain requires approximately 3.3 ml of oxygen per 100 g of brain tissue per minute. Initially, the body responds to lowered blood oxygen by redirecting blood to the brain and increasing cerebral blood flow. Blood flow may increase up to twice the normal flow but no more. If the increased blood flow is sufficient to supply the brain's oxygen needs then no symptoms will result. However, if blood flow cannot be increased or if doubled blood flow does not correct the problem, symptoms of cerebral hypoxia will begin to appear. Mild symptoms include difficulties with complex learning tasks and reductions in short-term memory. If oxygen deprivation continues, cognitive disturbances and decreased motor control will result. The skin may also appear bluish (cyanosis) and heart rate increases. Continued oxygen deprivation results in fainting, long-term loss of consciousness, coma, seizures, cessation of brain stem reflexes, and brain death. Objective measurements of the severity of cerebral hypoxia depend on the cause. Blood oxygen saturation may be used for hypoxic hypoxia, but is generally meaningless in other forms of hypoxia. In hypoxic hypoxia 95–100% saturation is considered normal; 91–94% is considered mild and 86–90% moderate. Anything below 86% is considered severe. Cerebral hypoxia refers to oxygen levels in brain tissue, not blood. Blood oxygenation will usually appear normal in cases of hypemic, ischemic, and histotoxic cerebral hypoxia.
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== Career == After graduating from Ohio State University in 1938, Minnich wrote to Carl Moore to ask for a job and he offered her a position as a research technician helping start a Hematology department at Washington University. She remained at Washington University for her entire career. She was promoted to a research associate in 1954, research assistant professor in 1958, research associate professor in 1963, and full professor of Medicine in 1974 (the first person without a doctorate degree to reach this rank at Washington University). She became professor emeritus in 1978 and retired in 1984. She also worked at Barnes Hospital in St. Louis from 1975 to the mid-1980s as assistant and then associate director of Hematology. She was regarded as an excellent teacher and, in addition to her official teaching responsibilities, she gave informal "night courses" to pathologists, lab technicians, and others. She created a series of audiovisual teaching materials describing the morphology of blood and bone marrow that were published by the American Society of Clinical Pathologists in the early 1980s as a 10-part course in morphologic hematology.
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It is a synthetic peptide analogue of growth hormone-releasing hormone. Four substitutions in its sequence make it more resistant to enzymatic degradation than the natural hormone. In the version carrying a drug affinity complex, the peptide binds albumin and remains in circulation for days.
No regulatory agency has approved CJC-1295 for clinical use. Human trials were conducted in the 2000s, but the development programme was discontinued before any marketing application succeeded. Material sold today is offered as a research chemical, and its purity depends on the supplier.
Sermorelin is an unmodified fragment of growth hormone-releasing hormone and is cleared quickly. CJC-1295 contains substitutions that resist breakdown, and the form with a drug affinity complex persists much longer. Both act at the same receptor but differ substantially in duration of action.
Chromatography reports how much material elutes as a single peak but does not confirm what that material is. Mass spectrometry supplies the molecular mass, which is characteristic of a given sequence and its modifications. Together the two methods support both a purity figure and an identity claim.