A practical reference on lyophilization: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-07-29. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Assessed by visual inspection under ordinary light |
| Primary analytical method | Reversed-phase liquid chromatography | Purity estimated from peak area at 214 nm |
| Confirmatory method | Mass spectrometry | Observed mass compared with calculated value |
| Powder storage temperature | Minus 20 degrees Celsius | Minus 80 for extended archival periods |
| Solution stability | Hours to days at 2 to 8 degrees Celsius | Influenced by pH, buffer, and concentration |
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.
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.
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.
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.
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.
== Legal status == As of October 2015, β-hydroxythiofentanyl is a controlled substance in China. As of May 2016, β-hydroxythiofentanyl was temporarily listed as a Schedule I controlled substance in the United States. A final ruling placing it in Schedule I was issued by the DEA on May 8, 2019 after a 1 year notice of proposed permanent scheduling. There were no petitions for hearings on the matter.
== Early life and education == Scrutton was born in Batley, West Riding of Yorkshire and was brought up in Cleckheaton where he went to Whitcliffe Mount School. Scrutton graduated from King's College London with a first class Bachelor of Science degree in Biochemistry in 1985. He was a Benefactors' Scholar at St John's College, Cambridge where he completed his doctoral research (PhD) in 1988 supervised by Richard Perham. He was a Research Fellow of St John's College, Cambridge (1989–92) and a Fellow / Director of Studies at Churchill College, Cambridge (1992–95). He was awarded a Doctor of Science (ScD) degree in 2003 by the University of Cambridge.
Reticular formation, a region in the brainstem that is involved in multiple tasks Reticular activating system, a set of connected nuclei in the brains of vertebrates Reticular cell, a type of fibroblast that produces reticular fibers Reticular connective tissue, a type of connective tissue that has a network of reticular fibers Reticular fiber, a type of fiber in connective tissue that is composed of type III collagen Reticular dermis, the lower layer of the dermis composed of dense irregular connective tissue Reticular dysgenesis, a rare genetic disorder of the bone marrow Reticular erythematous mucinosis, a skin condition that tends to affect women in the third and fourth decades of life Reticular layer, a layer in the adrenal cortex that produces androgens Reticular pigmented anomaly of the flexures, a fibrous anomaly of the flexures or bending parts of the axillae, neck and inframammary/sternal areas
Sources: en.wikipedia.org
=== Safety === Vitamin A toxicity (hypervitaminosis A) occurs when too much vitamin A accumulates in the body. It comes from consumption of preformed vitamin A but not of carotenoids, as conversion of the latter to retinol is suppressed by the presence of adequate retinol.
==== Potential complications ==== Several inpatient and outpatient procedures use sedation. Many drugs and agents used during surgery to relieve pain and to depress consciousness remain in the body at low amounts for hours or even days afterwards. In an individual with either central, obstructive or mixed sleep apnea, these low doses may be enough to cause life-threatening irregularities in breathing or collapses in a patient's airways. Use of analgesics and sedatives in these patients postoperatively should therefore be minimized or avoided. Surgery on the mouth and throat, as well as dental surgery and procedures, can result in postoperative swelling of the lining of the mouth and other areas that affect the airway. Even when the surgical procedure is designed to improve the airway, such as tonsillectomy and adenoidectomy or tongue reduction, swelling may negate some of the effects in the immediate postoperative period. Once the swelling resolves and the palate becomes tightened by postoperative scarring, however, the full benefit of the surgery may be noticed. A person with sleep apnea undergoing any medical treatment must make sure their doctor and anesthetist are informed about the sleep apnea. Alternative and emergency procedures may be necessary to maintain the airway of sleep apnea patients.
In February 2026, Carrey was awarded an Honorary César from the French Académie des Arts et Techniques du Cinéma. He appeared at the ceremony after a long absence from public life and looked and behaved significantly differently enough for some media to say that he was "nearly unrecognizable". His acceptance speech was delivered entirely in French, in which he recalled his family's French roots. The Internet was divided after makeup artist and impersonator Alexis Stone had said that he had transformed into Carrey that day. Despite that, Carrey's representative stated that the actor had been at the ceremony and he had accepted his award. Gregory Caulier, the organiser of the César awards, commented on the controversy with "for me, it's a non-issue". He noted that Carrey had been working on his speech for months.
Sources: en.wikipedia.org
Mass spectrometry establishes whether the observed molecular weight matches the calculated sequence mass. Chromatographic retention and fragment mapping add further confidence about sequence and composition. A single technique alone is rarely treated as sufficient evidence of identity.
Dry powder is markedly more stable than solution and is usually held frozen and desiccated. Room temperature exposure over days degrades it more slowly than most people assume, but long-term integrity favors freezer storage. Light protection is recommended regardless of temperature.
Methods, columns, gradients, and detection wavelengths are not standardized across laboratories. Some figures describe only the main peak area at one wavelength and ignore water, salts, or counter-ions. Without stated conditions, comparing reported percentages across sources is unreliable.
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.