If you have been reading about 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.
Last reviewed on 2026-03-31. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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 mass | Approximately 3.4 to 3.6 kDa | Depends on whether the affinity complex is attached |
| Appearance | White to off-white lyophilized powder | Freeze-dried solid, often in a sealed vial |
| Solubility | Soluble in water and aqueous buffers | Dissolution rate varies with pH and buffer salt |
| Typical storage | Below minus 20 degrees Celsius, dry and dark | Dissolved material is usually kept cold and used promptly |
| Common analytical methods | Reversed-phase HPLC and mass spectrometry | Peptide mapping and amino acid analysis add sequence detail |
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.
CJC-1295 acts at the growth hormone-releasing hormone receptor, a G-protein-coupled receptor found on somatotroph cells in the anterior pituitary. Binding triggers a rise in cyclic AMP and calcium entry, which promotes release of stored growth hormone. Because the peptide mimics the body's own releasing hormone, it amplifies existing secretory pulses rather than driving continuous output. The size of the response therefore depends partly on the subject's own hormonal rhythm and feedback state.
The attached maleimide group explains the unusual duration of the DAC version. After injection it reacts with the thiol of cysteine-34 on serum albumin, forming a stable covalent bond. The resulting conjugate is too large for rapid kidney filtration and is shielded from many peptidases. Reported half-lives for this form reach several days, whereas the version without the group is cleared in roughly half an hour. That gap is the main pharmacological difference between the two.
Downstream of growth hormone, the liver and other tissues increase production of insulin-like growth factor 1, a mediator of many growth-promoting effects. Studies have documented elevated levels of both hormones after dosing, and the rise from the long-acting form persists longer than that produced by shorter-acting analogues. What remains unclear is whether sustained elevation of these markers translates into meaningful clinical benefit, and whether prolonged exposure carries risks that short trials could not detect.
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.
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Although no cure for multiple sclerosis has been found, several therapies have proven helpful. Several effective treatments can decrease the number of attacks and the rate of progression. The primary aims of therapy are returning function after an attack, preventing new attacks, and preventing disability. Starting medications is generally recommended in people after the first attack when more than two lesions are seen on MRI. The first approved medications used to treat MS were modestly effective, though were poorly tolerated and had many adverse effects. Several treatment options with better safety and tolerability profiles have been introduced, improving the prognosis of MS.
=== Fellows of ASMS (since 2025) === 2026 Veronica M. Bierbaum, Catherine E. Costello, Kristina Hakansson, Lisa M. Jones, Susan D. Richardson 2025 Erin S. Baker, Catherine C. Fenselau, P. Jane Gale, Susan Weintraub
Sources: en.wikipedia.org
== Non-traditional use == In the late 20th century, the practice of ayahuasca drinking began spreading to Europe, North America and elsewhere. The first ayahuasca churches, affiliated with the Brazilian Santo Daime, were established in the Netherlands. A legal case was filed against two of the Church's leaders, Hans Bogers (one of the original founders of the Dutch Santo Daime community) and Geraldine Fijneman (the head of the Amsterdam Santo Daime community). Bogers and Fijneman were charged with distributing a controlled substance (DMT); however, the prosecution was unable to prove that the use of ayahuasca by members of the Santo Daime constituted a sufficient threat to public health and order such that it warranted denying their rights to religious freedom under ECHR Article 9. The 2001 verdict of the Amsterdam district court is an important precedent. Since then groups that are not affiliated to the Santo Daime have used ayahuasca, and a number of different "styles" have been developed, including non-religious approaches. In Peru, retreat centers such as Blue Morpho, founded by Hamilton Souther, in Iquitos began offering ayahuasca ceremonies to foreign visitors around 2004. International media coverage brought wider attention to the practice and coincided with the growth of ayahuasca tourism.
=== Influence of preparation methods === Depending on the preparation and cooking methods, the nutritional value of potatoes can vary greatly. In particular, its energy content, moderate in comparison with other starchy foods, can increase considerably when cooked with fat, and its vitamin content is affected to a greater or lesser extent depending on the cooking method. However, cooking is essential to make it an appetizing and especially digestible food. In the raw potato, the starch is mainly in the form of resistant starch, so called because it resists digestive enzymes such as amylase. Under the effect of heat, around 50 °C, the amylose swells and causes the starch grains to burst, which "gelatinize" and lose their "resistant" character. However, when the preparation is subsequently cooled, e.g. in salads, the proportion of resistant starch increases due to a retrogradation of the amylose. In boiled potatoes, this proportion can be about 2% (of the total starch) and in potato salad it can be as high as 6%. The resistant starch remains intact in the large intestine, playing a role similar to that of dietary fiber, which may be of interest in some diets. A 100 g portion of potatoes simply boiled in their skins provides 76 kcal, which is comparable to corn porridge, also 76 kcal, or plantain (94), but is significantly lower than the same portion of dried beans (115), pasta (132), rice (135) or bread (278). They are often paired or cooked with dietary fats, which can significantly increase the potato dishes caloric value.
==== Insulin ==== Perhaps the most common medication administered subcutaneously is insulin. While attempts have been made since the 1920s to administer insulin orally, the large size of the molecule has made it difficult to create a formulation with absorption and predictability that comes close to subcutaneous injections of insulin. People with type 1 diabetes almost all require insulin as part of their treatment regimens, and a smaller proportion of people with type 2 diabetes do as well — with tens of millions of prescriptions per year in the United States alone. Insulin historically was injected from a vial using a syringe and needle, but may also be administered subcutaneously using devices such as injector pens or insulin pumps. An insulin pump consists of a catheter which is inserted into the subcutaneous tissue, and then secured in place to allow insulin to be administered multiple times through the same injection site.
Neohormones are a group of recently evolved hormones primarily associated to the success of mammalian development. These hormones are specific to mammals and are not found in other vertebrates—this is because neohormones are evolved to enhance specific mammalian functions. In males, neohormones play important roles in regulating testicular descent (the testes descend into the scrotum during foetal development) and preparing the sperm for internal fertilisation (the sperm fertilizes the egg within the female). In females, neohormones are essential for regulating early pregnancy, mammary gland development lactation (secretion of milk from the mammary gland), and viviparity (allowing the fertilized egg to grow inside the female until they can exist independently). Neohormones superimpose their actions on the hypothalamic-pituitary-gonadal axis (a hormone system which regulates key reproductive functions in animals) and are not associated with other core bodily functions.
Sources: en.wikipedia.org
Elongation depends on elongation factors. At the end of the initiation step, the mRNA is positioned so that the next codon can be translated during the elongation stage of protein synthesis. The initiator TRNA occupies the P site in the ribosome, and the A site is ready to receive an aminoacyl-TRNA. During chain elongation, each additional amino acid is added to the nascent polypeptide chain in a three-step micro cycle. The steps in this micro cycle are (1) positioning the correct aminoacyl-TRNA in the A site of the ribosome, which is brought into that site by eEF1, (2) forming the peptide bond, and (3) shifting the mRNA by one codon relative to the ribosome with the help of eEF2. Unlike bacteria, in which translation initiation occurs as soon as the 5' end of an mRNA is synthesized, in eukaryotes, such tight coupling between transcription and translation is not possible because transcription and translation are carried out in separate compartments of the cell (the nucleus and cytoplasm). Eukaryotic mRNA precursors must be processed in the nucleus (e.g., capping, polyadenylation, splicing) in ribosomes before they are exported to the cytoplasm for translation. Translation can also be affected by ribosomal pausing, which can trigger endo nucleolytic attack of the TRNA, a process termed mRNA no-go decay. Ribosomal pausing also aids co-translational folding of the nascent polypeptide on the ribosome, and delays protein translation while it is encoding TRNA. This can trigger ribosomal frameshifting.
Miosis (constricted pupils) Vomiting Spasms of the stomach and intestines Hypoventilation (breathing that is too slow/shallow) Drowsiness, sleepiness, disorientation, sedation, unresponsiveness Skin that is cool, clammy (damp), and pale Blue fingernails and lips Limp muscles, trouble staying awake, nausea Unconsciousness and coma The respiratory depression of an overdose can be treated with naloxone. Naloxone is preferred to the newer, longer-acting antagonist naltrexone. Despite methadone's much longer duration of action compared to heroin and other shorter-acting agonists and the need for repeat doses of the antagonist naloxone, it is still used for overdose therapy. As naltrexone has a longer half-life, it is more difficult to titrate. If too large a dose of the opioid antagonist is given to a dependent person, it will result in withdrawal symptoms (possibly severe). When using naloxone, the naloxone will be quickly eliminated and the withdrawal will be short-lived. Doses of methadone take longer to be eliminated from the person's system. A common problem in treating methadone overdoses is that given the short action of naloxone (versus the extremely longer-acting methadone), a dosage of naloxone given to a methadone-overdosed person will initially work to bring the person out of overdose, but once the naloxone wears off, if no further naloxone is administered, the person can go right back into overdose (based upon time and dosage of the methadone ingested).
== Ionization == The gastrointestinal tract is lined with epithelial cells. Drugs must pass through or permeate these cells to be absorbed into the bloodstream. Cell membranes may act as barriers to some drugs. They are essentially lipid bilayers which form semipermeable membranes. Pure lipid bilayers are generally permeable only to small, uncharged solutes. Hence, whether or not a molecule is ionized will affect its absorption, since ionic molecules are charged. Solubility favors charged species, and permeability favors neutral species. Some molecules have special exchange proteins and channels to facilitate movement from the lumen into the circulation. Ions cannot passively diffuse through the gastrointestinal tract because the epithelial cell membrane is made up of a phospholipid bilayer, comprising two layers of phospholipids in which the charged hydrophilic heads face outwards and the uncharged hydrophobic fatty acid chains are in the middle of the layer. The fatty acid chains repel ionized, charged molecules. This means that the ionized molecules cannot pass through the intestinal membrane and be absorbed. The Henderson-Hasselbalch equation offers a way to determine the proportion of a substance that is ionized at a given pH. In the stomach, drugs that are weak acids (such as aspirin) will be present mainly in their non-ionic form, and weak bases will be in their ionic form. Since non-ionic species diffuse more readily through cell membranes, weak acids will have a higher absorption in the highly acidic stomach.
Sources: en.wikipedia.org
The version carrying the affinity complex bears a maleimide group that binds serum albumin, which extends its circulation time to several days. The version without it lacks this group and clears within roughly half an hour. The two are chemically related but behave very differently once in the body.
In common usage the name without the affinity complex is often equated with MOD GRF 1-29, a fragment carrying four stabilizing substitutions. Strictly speaking, the term originally referred to the albumin-binding version. The overlap in naming causes frequent ambiguity in both informal and technical writing.
Reversed-phase chromatography separates the peptide from related impurities and yields a purity estimate. Mass spectrometry confirms the molecular mass and detects modifications such as oxidation. Sequence-level checks rely on peptide mapping or amino acid analysis when stronger confirmation is needed.
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.