A practical reference on Reversed-phase HPLC: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-09-11. Anything still debated is marked as such rather than presented as settled.
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.
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.
The dividing feature between the two forms is a maleimide-based drug affinity complex, abbreviated DAC. In the DAC-bearing version, a linker attaches the peptide to serum albumin after administration, and that association slows removal from plasma. The version lacking DAC appears in catalogs as MOD GRF(1-29) or tetrasubstituted GRF(1-29). Because informal writing treats both as one item, comparisons drawn from such sources routinely blend measurements taken from two molecules with substantially different behavior.
Four amino acid substitutions separate the modified backbone from the parent GRF(1-29) sequence. These changes reduce recognition by dipeptidyl peptidase IV and related proteases, extending the interval before degradation. Development work in this area sought longer-acting GHRH analogs for endocrine investigation. Published descriptions treat the substitution set as a defining property of the core sequence, while the albumin-binding linker is described separately as an optional addition to that same backbone.
CJC-1295 is a synthetic peptide analog of growth hormone-releasing hormone, constructed on the 29-amino-acid fragment designated GRF(1-29). The name began as an internal development code during the 1990s and later spread through research supply catalogs and discussion forums. The molecule does not occur in nature; its sequence is engineered rather than isolated from tissue. Two related compounds are sold under this single label, and they differ by one appended chemical group that strongly influences how long the peptide remains in circulation.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic peptide | GHRH analog, not a steroid |
| Backbone length | 29 amino acids | Based on GRF(1-29) |
| Substitutions | Four positions | D-Ala2, Gln8, Ala15, Leu27 |
| Appearance | White to off-white powder | Typical lyophilized research material |
| Common synonyms | Modified GRF(1-29) | Usage varies between sources |
Purity is most often assessed by reversed-phase high-performance liquid chromatography, reported as a percentage of total peak area. Identity is confirmed by mass spectrometry, which yields a molecular ion consistent with the expected sequence. Amino acid analysis and peptide mapping provide additional characterization. Reported purity values are method-dependent, so figures from different laboratories are not always directly comparable without details of column, gradient, and detection wavelength.
Peptide degradation proceeds mainly through hydrolysis, oxidation of methionine, and deamidation of asparagine or glutamine residues. The maleimide group on the albumin-binding variant can also react with thiols or hydrolyze in aqueous media. Because these pathways accelerate with temperature and pH extremes, handling conditions strongly influence measured stability. Stability data in the public literature are limited and often generated under differing conditions, so general statements about shelf life should be read as approximate.
Research material is normally supplied as a freeze-dried powder in sealed vials. In that state the peptide is comparatively robust, but prolonged exposure to warmth, moisture, or light accelerates degradation. Storage at minus twenty degrees Celsius or lower, with desiccant and protection from light, is the commonly described practice. Vials should be allowed to reach room temperature before opening to limit condensation on the powder. Moisture uptake during handling is a recognized source of variability in later measurements.
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.
Stability depends heavily on physical state. A lyophilized powder kept dry, desiccated, and shielded from light typically holds its integrity for months to years at minus twenty degrees Celsius, and longer at minus eighty. Once dissolved, the peptide becomes far more vulnerable, since peptide bond hydrolysis, oxidation of susceptible residues, and aggregation all proceed faster in solution. Buffers near neutral pH are generally gentler than strongly acidic or alkaline conditions. Repeated freeze-thaw cycles and exposure to air-liquid interfaces during vigorous mixing cause losses that are easy to overlook.
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.
== Research == Alström Syndrome was first discovered by Swedish psychiatrist, Carl-Henry Alström and his three associates, B. Hallgren, I. B. Nilsson and H. Asander, in 1946. Alström and his colleagues published their first manuscript in 1959, which contained a very thorough investigation of three patients with a recessive combination of retinal degeneration, obesity, sensorineural hearing loss, and diabetes, which are all extremely common symptoms in AS. The syndrome was first known as Alström-Hallgren Syndrome, but has since been more widely known as just Alström Syndrome. In 2001 Jackson Laboratory in Bar Harbor, Maine, USA with the University of Southampton, UK isolated the single gene (ALMS1) responsible for Alström syndrome. The Jackson Laboratory created the very first mouse model for AS, Alms1-/-, or more colloquially known as "Carl Henry Mouse" in 2004. These mice continue to be used in research studies to simulate the symptoms of an individual with AS.
Free-flow electrophoresis (FFE) is a carrier-free electrophoresis technique that allows preparative protein separation in a laminar buffer stream by using an orthogonal electric field. By making use of a pH-gradient, that can for example be induced by ampholytes, this technique allows to separate protein isoforms up to a resolution of < 0.02 delta-pI.
The dangers of radium were recognized in the early 1920s and first described in 1924 by New York dentist and oral surgeon Theodor Blum (1883-1962). He was particularly aware of the use of radium in the watch industry, where it was used for luminous dials. He published an article on the clinical picture of the so-called radium jaw. He observed this disease in female patients who, as dial painters, came into contact with luminous paint whose composition was similar to Radiomir, a luminous material invented in 1914 consisting of a mixture of zinc sulfide and radium bromide. As they painted, they used their lips to form the tip of the phosphorus-laden brush into the desired pointed shape, and this is how the radioactive radium entered their bodies. In the U.S. and Canada alone, about 4,000 workers were affected over the years. In retrospect, the factory workers were called the Radium Girls. They also played with the paint, painting their fingernails, teeth and faces. This made them glow at night to the surprise of their companions.
=== In pharmacology === Bioavailability is a term used to describe the percentage of an administered dose of a xenobiotic that reaches the systemic circulation unchanged. It is denoted by the letter f (or, if expressed in percent, by F).
Sources: en.wikipedia.org
The problem, attributed to technical problems, is resolved by the following evening. 27 May – Post Office Limited issues an apology over the use of racist terms to describe postmasters wrongly investigated as part of the Horizon IT scandal. 28 May The Home Office announces it is launching an ad campaign on social media in Albania to deter migrants from coming to the UK; the campaign begins the following day. BBC News reports that Andrei Kelin, Russia's ambassador to the UK, has warned that the west's supply of weapons to Ukraine risks escalating the war to levels not seen so far. 29 May Mars bars, one of the top-selling chocolate bars in the UK, are given a new look with recyclable paper wrappers, in a bid to cut down on the growing problem of plastic waste. The Met Police's plan to stop attending emergency mental health incidents is described as "potentially alarming" by a former inspector of constabulary, with charity Mind also expressing concerns. 30 May Figures published by the British Retail Consortium show that supermarket prices rose in May, largely because of the price of coffee, chocolate and non-food goods. The UK government announces plans to close a loophole in the law that allows shopkeepers to give free vape samples to those under the age of majority. 31 May Two people die and eight others are injured during an incident at the beach in Bournemouth. ASLEF members hold their latest strike as part of an ongoing dispute over pay and conditions, causing widespread disruption to rail services.
It was estimated in 2017 that nearly one in three persons globally had at least one form of malnutrition: wasting, stunting, vitamin or mineral deficiency, overweight, obesity, or diet-related noncommunicable diseases. Undernutrition is more common in developing countries. Stunting is more prevalent in urban slums than in rural areas. Studies on malnutrition have the population categorised into different groups including infants, under-five children, children, adolescents, pregnant women, adults and the elderly population. The use of different growth references in different studies leads to variances in the undernutrition prevalence reported in different studies. Some of the growth references used in studies include the National Center for Health Statistics (NCHS) growth charts, WHO reference 2007, Centers for Disease Control and Prevention (CDC) growth charts, National Health and Nutrition Examination Survey (NHANES), WHO reference 1995, Obesity Task Force (IOTF) criteria and Indian Academy of Pediatrics (IAP) growth charts. In 2023, an estimated 28.9 percent of the global population – 2.33 billion people – were moderately or severely food insecure.
Fascia training describes sports activities and movement exercises that attempt to improve the functional properties of the muscular connective tissues in the human body, such as tendons, ligaments, joint capsules and muscular envelopes. Also called fascia, these tissues take part in a body-wide tensional force transmission network and are responsive to training stimulation. As of 2018 the body-wide continuity of this tensional system has been expressed in an educational manner within the Fascial Net Plastination Project. The FNPP brought together experts in anatomy, dissection, and plastination, and it was the first project of its kind to plastinate a complete human fascia specimen.
Sources: en.wikipedia.org
No. It is a laboratory-made analog of growth hormone-releasing hormone. The natural hormone is a 44-residue peptide, while the analog is built on a shorter 29-residue fragment.
The original material included a linker that binds serum albumin. A later variant removed that linker to reduce the duration of action. Catalogs and papers did not consistently adopt separate names, so both remain widely labeled with the same term.
The amino acid sequence and the presence or absence of the linker group. Mass measured by spectrometry gives an independent check that separates the two forms.
No. It is a laboratory-synthesized analog built on a fragment of the natural hormone. The natural peptide is shorter-lived and lacks the stabilizing substitutions found in the synthetic version.