MOD GRF(1-29) 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 2025-12-10. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
At the pituitary, the peptide binds the growth hormone-releasing hormone receptor on somatotroph cells. Receptor activation raises intracellular cyclic AMP and triggers release of stored growth hormone. Somatostatin and other hypothalamic signals modulate this response. Negative feedback from insulin-like growth factor 1 also influences output. The same regulatory architecture operates with the native hormone. Whether the synthetic analog alters feedback dynamics over repeated exposure remains an open question. Most published receptor work uses cell models rather than intact human systems.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic peptide | Analog of growth hormone-releasing hormone |
| Chain length | 29 amino acids | Based on the GRF(1-29) fragment |
| Appearance | White to off-white lyophilized powder | Common research supply form |
| Solubility | Soluble in water and aqueous buffers | Powder requires reconstitution before use |
| Typical storage | −20 °C or below | Kept away from light and moisture |
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.
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.
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.
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.
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.
== Molecular properties and chemical space of peptides == The chemical space of peptides is defined as a multidimensional landscape shaped by molecular descriptors or fingerprints. Within these frameworks, the distance between specific molecules serves as a proxy for chemical or functional similarity. This space can be mapped using primary amino acid sequences, three-dimensional structural data, or a combination of both. Key molecular properties used for mapping include molecular weight, lipophilicity (logP and logD), topological polar surface area (TPSA), and hydrogen-bond dynamics. Dimensionality-reduction techniques—such as Principal Component Analysis (PCA), t-SNE, and UMAP—are frequently employed alongside clustering algorithms to visualize peptide libraries and identify clusters with related biological activities. Peptides are distinguished from traditional small molecules by their unique combination of residue sequence, amide backbone flexibility, and susceptibility to chemical modifications, all of which dictate bioavailability and membrane permeability. Computational analysis is supported by notation systems like FASTA, HELM, and BILN for encoding both canonical and modified sequences. Modifications such as cyclization or the integration of non-natural amino acids significantly shift a peptide's position within the chemical space, altering its stability and target affinity. Consequently, chemical-space analysis is a vital tool for virtual screening and the discovery of shared bioactivity regions across different peptide families.
== Availability == In December 2013, in anticipation of the rescheduling of alprazolam to Schedule 8 in Australia, Pfizer Australia announced they would be discontinuing the Xanax brand in Australia as it was no longer commercially viable.
== Definition == Thiamine is one of the B vitamins and is also known as vitamin B1. It is a cation that is usually supplied as a chloride salt. In its pure form, thiamine appears as a white or slightly off-white crystalline powder, with a distinctive, unpleasant odor and bitter flavor. It is soluble in water, methanol and glycerol, but practically insoluble in less polar organic solvents. In the body, thiamine can form derivatives; the most well-characterized of which is thiamine pyrophosphate (TPP), which acts as a coenzyme in the catabolism of sugars and amino acids—one of the vitamin's important biological roles. The chemical structure consists of an aminopyrimidine and a thiazolium ring linked by a methylene bridge. The thiazole is substituted with methyl and hydroxyethyl side chains. Thiamine is stable at acidic pH, but it is unstable in alkaline solutions and from exposure to heat. It reacts strongly in Maillard-type reactions. Oxidation yields the fluorescent derivative thiochrome, which can be used to determine the amount of the vitamin present in biological samples.
== Reactions == Hippuric acid is readily hydrolysed by hot caustic alkalis to benzoic acid and glycine. Nitrous acid converts it into benzoyl glycolic acid, C6H5C(=O)OCH2CO2H. Its ethyl ester reacts with hydrazine to form hippuryl hydrazine, C6H5CONHCH2CONHNH2, which was used by Theodor Curtius for the preparation of hydrazoic acid. Hippuric acid has also been used in Erlenmeyer–Plöchl synthesis of phenylalanine and other amino acids, the reaction proceeding via an oxazolone or "azlactone" intermediate.
Sources: en.wikipedia.org
== Use in imaging == Imaging is a useful tool in visualization of the radioligand after injection, with positron emission tomography (PET) and single-photon emission computed tomography (SPECT) being the most common types of imaging. PET scans are often utilized after radioligand administration because of the ease of use, image accuracy, and non-invasive nature. While PET and SPECT scans function similarly when imaging radioligands, the main difference lies in the type of radiation used, with PET scans utilizing positrons and SPECT utilizing gamma rays. When comparing the two modalities, PET offers much better image quality and high diagnostic proficiency, however, the high cost and the short half-lives of the positron-emitting isotopes limit their overall availability. Alternatively, SPECT imaging is more dynamic because of the lower cost burden and longer half-lives of single-photon emitters. With advances in technology came hybrid imaging that can combine PET, SPECT, computed tomography (CT), and magnetic resonance imaging (MRI). Some hybrid imaging modalities include: PET–CT, SPECT/CT, and PET/MRI. Although combined imaging presents both cost and availability barriers, the technology is an extremely useful diagnostic tool. Often, the patient does not have to be moved for both imaging types to be completed, and the clinicians are provided with rich, multi-dimensional imaging.
== Regulation == IGFBP-3 levels in human serum are, like IGF-1, dependent on growth hormone (GH); for example, serum IGFBP-3 is increased in acromegaly and low in GH-deficient children. However, IGFBP-3 gene expression in human liver is GH-independent. Because it is stabilized in human serum by forming complexes with IGF-1 and ALS, which are both GH-dependent, serum IGFBP-3 also appears regulated by GH. Its production by some non-hepatic tissues may also be directly GH-regulated. Immunoassays for serum IGFBP-3 are often used as part of the diagnosis of childhood GH-deficiency. The most widely studied IGFBP3 polymorphism, at nucleotide-202 in the promoter region, is significantly associated with circulating IGFBP-3 levels, although the mechanism is unclear. In some studies circulating IGFBP-3 also appears to be nutritionally regulated, although this may not be seen at the mRNA level. IGFBP-3 has been identified in human lymph, nipple aspirate, milk, amniotic fluid, follicular fluid, seminal plasma, urine, peritoneal dialysate, synovial fluid, tear fluid, and cerebrospinal fluid, in addition to serum. Many factors increase IGFBP-3 production by cells, including transforming growth factor-β (TGFβ), tumor necrosis factor-α, vitamin D, retinoic acid, IGF-1, and stimuli such as chemotherapy that activate the tumor suppressor p53. Estrogen inhibits IGFBP-3 production, and its tissue levels are lower in estrogen receptor (ER)-positive breast cancers than in ER-negative cancers.
=== 2013–2015: Top five best and fairest finish then inconsistency === The first intra-club match during the 2013 pre-season saw Melksham break his hand, which required surgery, he managed to return for the NAB Cup, playing his first match in round two. He played the first four matches of the season before he was omitted for the Anzac Day match against Collingwood in round five, he played in the VFL that weekend for Essendon's reserves side in the thirty-five-point win against North Ballarat and was named in the best players, which saw him return to the senior side for the thirty-nine-point win against Greater Western Sydney at Etihad Stadium in round six. He found himself in trouble when he was reported for rough conduct against Jarryd Roughead during the fifty-six-point loss against Hawthorn at Etihad Stadium in round eighteen, he subsequently received a reprimand from the match review panel. An incident during the final round match against Richmond saw him receive a two-match suspension for striking Daniel Jackson. He played twenty-one matches for the year with The Age journalist, Rohan Connolly stating his form had improved from the previous year; this was reflected in his fifth-place finish in the club best and fairest count. He was also rewarded with a two-year contract extension, tying him to the club until the end of the 2015 season.
Sources: en.wikipedia.org
== Personal life == Collins lives in Roxwell, Chelmsford in a barn conversion which she bought for £1.35 million in 2021. She has described the house as her "dream home" and has had multiple renovations including a swimming pool and a summer house. Collins enjoys gardening and has expressed her love of plants, as well as her passion for animals and nature. She has two dogs and two cats, as well as chickens. Collins has several life-size animal sculptures inside her home and in her garden, including a horse with a disco ball and a giraffe lamp, as well as a wooden Asian mother elephant and its calf, the former of which she donated £22,000 to CoExistence, an environmental art campaign conceptualised by the Elephant Family.
Alprazolam, sold under the brand name Xanax among others, is a fast-acting, potent tranquilizer of moderate duration within the triazolobenzodiazepine group of chemicals called benzodiazepines. Alprazolam is most commonly prescribed in the management of anxiety disorders, especially panic disorder and generalized anxiety disorder (GAD). Other uses include the treatment of chemotherapy-induced nausea, together with other treatments. Alprazolam is generally taken orally. Common side effects include sleepiness, depression, suppressed emotions, mild to severe decreases in motor skills, hiccups, dulling or declining of cognition, decreased alertness, dry mouth (mildly), decreased heart rate, impairment of judgment (usually in higher than therapeutic doses), and decreased memory formation, depending on dosage. Some of the sedation and drowsiness may improve within a few days. Benzodiazepine withdrawal symptoms may occur if use is suddenly decreased. Alprazolam was developed by Jackson Hester Jr. at the Upjohn Company and patented in 1971 and approved for medical use in the United States in 1981. Alprazolam is a Schedule IV controlled substance and is a common drug of abuse. It is available as a generic medication. In 2023, it was the 37th most commonly prescribed medication in the United States, with more than 15 million prescriptions.
=== Legal status === Rezafungin was approved for medical use in the United States in March 2023, The FDA granted the application for rezafungin orphan drug, fast track, and priority review designations. In October 2023, the Committee for Medicinal Products for Human Use of the European Medicines Agency adopted a positive opinion, recommending the granting of a marketing authorization for the medicinal product Rezzayo, intended for the treatment of invasive candidiasis in adults. The applicant for this medicinal product is Mundipharma GmbH. Rezafungin was approved for medical use in the European Union in December 2023.
Sources: en.wikipedia.org
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.
DAC stands for drug affinity complex, a chemical group that binds the peptide to serum albumin. The binding slows clearance and lengthens the time the molecule stays in plasma compared with the unmodified analog.
Because two distinct molecules are discussed under one informal label. The albumin-binding version clears over several days, while the form without that group clears within roughly half an hour. Mixing results from both creates inconsistent figures.
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.