If you have been reading about drug affinity complex 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.
Last reviewed on 2026-05-03. Where a claim depends on a specific study, the study is described rather than over-claimed.
The peptide backbone includes a D-alanine at position two, which resists cleavage by dipeptidyl peptidase IV, and several other substitutions that reduce degradation. Its molecular weight is roughly 3.4 kDa without the linker and about 3.6 kDa with it. The molecule is water soluble and is normally supplied as a lyophilized powder. Precise sequence and mass values depend on which variant is described, so technical documents usually state the exact form being referenced.
CJC-1295 is a synthetic peptide designed as a long-acting analogue of growth hormone-releasing hormone (GHRH). Its structure derives from the first 29 amino acids of native GHRH, a fragment often called GRF(1-29). Four substitutions were introduced to slow enzymatic breakdown and extend activity relative to the natural sequence. The compound was developed by ConjuChem as part of a broader effort to improve the pharmacokinetic profile of peptide hormones. It is studied in laboratory and clinical research settings rather than appearing as a naturally occurring substance.
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.
CJC-1295 is a synthetic peptide modeled on growth hormone-releasing hormone, the hypothalamic signal that prompts the pituitary to release growth hormone. Its sequence corresponds to the first twenty-nine residues of human GHRH, with four substitutions that slow enzymatic breakdown. Early descriptions placed the compound in research on growth hormone deficiency and related conditions, and later literature groups it with the long-acting GHRH analogs. The name appears in both laboratory and popular fitness writing, where it sometimes labels chemically different peptides.
| Property | Value | Notes |
|---|---|---|
| Molecular weight (no linker) | ~3.37 kDa | Calculated from peptide sequence |
| Molecular weight (with linker) | ~3.65 kDa | Includes albumin-binding moiety |
| Appearance | White to off-white powder | Typically lyophilized |
| Solubility | Soluble in water | Also dissolves in aqueous buffers |
| Common synonyms | Modified GRF(1-29), DAC:GRF | Usage varies by source |
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.
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.
Studies in this area generally track growth hormone pulses, insulin-like growth factor 1 concentrations, and occasionally body composition endpoints. Most published human data come from early, small trials, and questions about long-term effects remain open. Whether repeated exposure alters pituitary responsiveness over time is not settled. Analytical work relies on immunoassays for the hormones and on mass spectrometry for the peptide itself, because the two measurements answer different questions.
Binding of the peptide to the growth hormone-releasing hormone receptor on pituitary somatotrophs triggers a G protein coupled cascade that raises cyclic AMP and opens calcium channels. The result is greater secretion of growth hormone into the bloodstream. Because the peptide acts at the same receptor as the natural hypothalamic hormone, its effect is amplified pulse size rather than an entirely separate release pathway. Receptor binding alone does not determine the response, since somatostatin tone and other inputs modulate the final output.
During the many years I spent on the Left, the cause of self-determination for Kurdistan was high on the list of principles and priorities – there are many more Kurds than there are Palestinians and they have been staunch fighters for democracy in the region. He also wore a lapel pin with the flag of Kurdistan on it, to show his solidarity with the Kurds.
==== Fishkeeping ==== Hydrogen peroxide is used in aquaculture for controlling mortality caused by various microbes. In 2019, the U.S. FDA approved it for control of Saprolegniasis in all coldwater finfish and all fingerling and adult coolwater and warmwater finfish, for control of external columnaris disease in warm-water finfish, and for control of Gyrodactylus spp. in freshwater-reared salmonids. It can also be used to increase the oxygen content of water to enable fish to survive otherwise-hypoxic conditions. The hydrogen peroxide releases oxygen by decomposition when it is exposed to catalysts such as manganese dioxide. Sodium percarbonate, a complex containing hydrogen peroxide as its active agent, is sold for oxygenation in acutely oxygen-deficient water to enable fish survival.
== Phase 1 == For the first phase, the WHO formed a team of ten researchers with expertise in virology, public health and animals to conduct a thorough study. One of the team's tasks was to retrospectively ascertain what wildlife was being sold in local wet markets in Wuhan. The WHO's phase one team arrived and quarantined in Wuhan, Hubei, China in January 2021. Members of the team included Thea Fisher, John Watson, Marion Koopmans, Dominic Dwyer, Vladimir Dedkov, Hung Nguyen-Viet, Fabian Leendertz, Peter Daszak, Farag El Moubasher, and Ken Maeda. The team also included five WHO experts led by Peter Ben Embarek, two Food and Agriculture Organization representatives, and two representatives from the World Organisation for Animal Health. The inclusion of Peter Daszak in the team stirred controversy. Daszak is the head of EcoHealth Alliance, a nonprofit that studies spillover events, and has been a longtime collaborator of over 15 years with Shi Zhengli, Wuhan Institute of Virology's director of the Center for Emerging Infectious Diseases. While Daszak is highly knowledgeable about Chinese laboratories and the emergence of diseases in the area, his close connection with the WIV was seen by some as a conflict of interest in the WHO's study. When a BBC News journalist asked about his relationship with the WIV, Daszak said, "We file our papers, it's all there for everyone to see."
== Notation == In GSH, G stands for glutathione as a whole molecule, is not the one-letter amino-acid code for glycine. So GSH means: G–SH = glutathione with a free thiol group. Glutathione as a tripeptide is γ-Glu–Cys–Gly, or in one-letter residue notation γ-ECG. It oxidizes into glutathione disulfide (GSSG), where the SS denotes the disulfide bond between two glutathiones.
Sources: en.wikipedia.org
Vitamin B17: pseudoscientific name for the poisonous compound amygdalin, also known as "laetrile" or by the equally pseudoscientific name "nitrilosides" despite the fact that it is a single compound. Amygdalin can be found in various plants, but is most commonly extracted from apricot pits and other similar fruit kernels. Amygdalin is hydrolyzed by various intestinal enzymes to form, among other things, hydrogen cyanide, which is toxic to human beings when exposed to a high enough dosage. Some proponents claim that amygdalin is effective in cancer treatment and prevention, despite its toxicity and a lack of scientific evidence. Vitamin B20: L-carnitine. Vitamin Bf: carnitine. Vitamin Bm: myo-inositol, also called "mouse antialopaecia factor". Vitamin Bp: "antiperosis factor", which prevents perosis, a leg disorder, in chicks; can be replaced by choline and manganese salts. Vitamin BT: carnitine. Vitamin Bv: a type of B6 other than pyridoxine. Vitamin BW: a type of biotin other than d-biotin. Vitamin Bx: an alternative name for both pABA (see vitamin B10) and pantothenic acid.
== Further reading == Johnson JE, Cornell RB (1999). "Amphitropic proteins: regulation by reversible membrane interactions (review)". Molecular Membrane Biology. 16 (3): 217–35. doi:10.1080/096876899294544. PMID 10503244. Alenghat FJ, Golan DE (2013). "Membrane protein dynamics and functional implications in mammalian cells". Current Topics in Membranes. 72: 89–120. doi:10.1016/b978-0-12-417027-8.00003-9. ISBN 9780124170278. PMC 4193470. PMID 24210428.{{cite journal}}: CS1 maint: periodical has ISBN (link)
WHO suggests preventing dermal exposure by occupational hygiene measures such as surface cleaning, and the use of appropriate gloves (conditional recommendation, low quality evidence). When assessment and measurement by a workplace safety expert is not available, WHO suggests using control banding for nanomaterials to select exposure control measures in the workplace. Owing to a lack of studies, WHO cannot recommend one method of control banding over another (conditional recommendation, very low-quality evidence). For health surveillance WHO could not make a recommendation for targeted MNM-specific health surveillance programmes over existing health surveillance programmes that are already in use owing to the lack of evidence. WHO considers training of workers and worker involvement in health and safety issues to be best practice but could not recommend one form of training of workers over another, or one form of worker involvement over another, owing to the lack of studies available. It is expected that there will be considerable progress in validated measurement methods and risk assessment and WHO expects to update these guidelines in five years' time, in 2022.
The Serbsky Center, Moscow Institute of Psychiatry, and Russian Center of Vegetative Pathology are reported to have confirmed the effectiveness of phenylpiracetam describing the following effects: improvement of regional blood flow in ischemic regions of the brain, reduction of depressive and anxiety disorders, increase the resistance of brain tissue to hypoxia and toxic effects, improving concentration and mental activity, a psycho-activating effect, increase in the threshold of pain sensitivity, improvement in the quality of sleep, and an anticonvulsant action, though with the side effect of an anorexic effect in extended use.
=== DeBakey === The DeBakey system, named after cardiothoracic surgeon Michael E. DeBakey, is an anatomical description of the aortic dissection. It categorizes the dissection based on where the original intimal tear is located and the extent of the dissection (localized to either the ascending aorta or descending aorta or involving both the ascending and descending aorta).
Sources: en.wikipedia.org
No. It is a synthetic analogue modeled on the first 29 residues of human GHRH. The substitutions and any linker are laboratory modifications rather than features of the endogenous peptide.
Early development used the albumin-binding form, and a shorter variant was later discussed under the same label. Because the two differ in half-life and handling, ambiguity arises whenever a source omits the variant designation.
The compound derives from that fragment but is not identical to it. The parent fragment lacks the stabilizing substitutions, so its degradation rate and duration of action differ noticeably.
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.