This is a working overview of freeze-thaw, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-03-18 and is reviewed periodically as new material appears.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Physical form | Lyophilized white powder | Supplied as a freeze-dried solid for research use |
| Molecular weight | Approximately 3,647 Da (DAC form) | Lower for the variant lacking the albumin-binding moiety |
| Solubility | Soluble in water and aqueous buffer | Typically dissolved in sterile or bacteriostatic water |
| Typical storage temperature | −20 °C or below | Dry powder, desiccated and protected from light |
| Common analytical method | Reversed-phase HPLC with mass spectrometry | Used for purity estimation and identity confirmation |
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.
Lyophilised powder is the usual supplied form. The material is hygroscopic, so vials are typically equilibrated to room temperature before opening in order to prevent condensation on the contents. Long-term storage is generally described at minus twenty degrees Celsius or colder, protected from light and moisture. Repeated freeze-thaw cycles are avoided because they promote aggregation and loss of soluble material. A reconstituted solution is considerably less stable than the dry powder and is normally kept refrigerated for short periods only.
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.
The compound emerged from work at a Canadian biotechnology firm in the early 2000s. Early human studies examined its effect on growth hormone and insulin-like growth factor 1 in healthy volunteers and in people with HIV-associated fat redistribution. Reports described sustained increases in both markers after a single injection. Development did not advance to regulatory approval, and the clinical programme was later discontinued. The molecule is now encountered mainly as a research chemical rather than a marketed medicine.
Two forms circulate in research settings and are frequently confused. One carries the drug affinity complex and is often written as CJC-1295 with DAC; the other lacks that group and is usually called modified GRF(1-29). The two share the same core sequence but differ sharply in how long they persist in blood. Products labelled only as CJC-1295 normally refer to the version carrying the complex. Documentation that omits the distinction leaves the intended molecule ambiguous.
=== Early years === While an undergraduate student at Stanford University, Holmes had an idea to develop a wearable patch that could adjust the dosage of drug delivery and notify doctors of variables in patients' blood. She started developing lab-on-a-chip technology for blood tests, with the idea to start a company that would make blood tests cheaper, more convenient and accessible to consumers. Holmes dropped out of Stanford in 2003 and used the education trust from her parents to found the company that would later be called Theranos, derived from a combination of the words "therapy" and "diagnosis". The original name was "Real-Time Cures", which Holmes changed after deciding that people were skeptical of the word "cure". By December 2004, Holmes had raised $6 million to fund the firm. By the end of 2010, Theranos had more than $92 million in venture capital. In July 2011, Holmes was introduced to former US secretary of state George Shultz. After a two-hour meeting, he joined the Theranos board of directors. Holmes was recognized for forming "the most illustrious board in U.S. corporate history" over the next three years.
In general, a starting molecule is adhered to a solid support (typically an insoluble polymer), then additional reactions are performed, and the final product is purified and then cleaved from the solid support. Since the molecules of interest are attached to a solid support, it is possible to reduce the purification after each reaction to a single filtration/wash step, eliminating the need for tedious liquid-liquid extraction and solvent evaporation steps that most synthetic chemistry involves. Furthermore, by using heterogeneous reactants, excess reagents can be used to drive sluggish reactions to completion, which can further improve yields. Excess reagents can simply be washed away without the need for additional purification steps such as chromatography.
=== Pharmacokinetics === Kavalactones are quickly absorbed in the gut and vary in bioavailability. They primarily act on brain areas like the limbic system, amygdala, and reticular formation, but their exact molecular mechanisms are not yet fully understood. Data on the pharmacokinetics of kavalactones remain limited. In animal studies, particularly in rats, kavain—the primary kavalactone found in traditional kava preparations—was shown to be well absorbed, with an estimated bioavailability of approximately 50%. In humans, kavain undergoes extensive hepatic metabolism, primarily via cytochrome P450 (CYP) enzyme-mediated pathways, followed by further phase II biotransformation processes such as sulfonation, glucuronidation, and glutathione (GSH) conjugation. In rats administered a 100 mg/kg bodyweight dose of kavain, over 90% was eliminated within 72 hours through urine and feces, either as unchanged compound or as metabolites. No evidence of bioaccumulation has been observed in rats, mice, or humans.
== January 7, 1982 (Thursday) == The American steelmaker U.S. Steel expanded it conglomerate by purchasing the U.S. oil and gasoline company Marathon Oil. The Soviet Union halted any further manufacture of the Tupolev Tu-144 supersonic passenger jet. The United States Mint began the transition from copper American pennies to a composition of zinc with copper-plating, and minted the first zinc one-cent pieces. Born: Yul Edochie, Nigerian film and TV actor; in Lagos Gabrielius Landsbergis, Foreign Minister of Lithuania from 2020 to 2024; in Vilnius, Lithuanian SSR, Soviet Union Died: Frank Van der Veer, 60, American special effects producer for multiple films from 1974 until his death, with creations that continued to be used until 1992, and 1976 Academy Award winner Almond E. Fisher, 68, U.S. Army officer and Medal of Honor recipient for heroism in 1944 World War II
Sources: en.wikipedia.org
== Chemistry == Do6a is the most abundant peptide in D. occidentalis venom with an EC50 of 113 nM which is much lower than that of other peptides in the same venom (for example, Do10a has an EC50 of 75 μM). The sequence of Do6a shares similarities in both amino acid composition and length to a known endogenous pain signaling peptide; Vulnusin. Vulnusin, which is present in Drosophila larvae, signals the larvae to initiate puncture-induced rolling as a defense strategy for moving away from parasitoid wasps. Compared to Do6a, Vulnusin has a significantly lower EC50, making it more potent. Nevertheless, there are speculations that velvet ants evolved venom peptides similar to vulnusin in order to target the same ion channel complex. Despite being the most potent and concentrated peptide in red velvet ant venom, Do6a alone does not appear to give rise to any considerable nocifensive responses in mice, such as paw licking. Even when administered at concentrations up to 10,000 higher than the EC50 for larval nociceptor activation, its effects in mice remain negligible. This indicates that the mode of action underlying Do6a-induced nociception differs between mammals and insects.
In another study, researchers evaluated synthetic platelet (SP) nanoparticles in mouse models of von Willebrand disease (vWD). In vitro, SPs enhanced thrombus formation under vWF-deficient conditions using human platelets. In vivo, SP treatment reduced blood loss by 35% in type 2B VWD mice and 68% in vWF knockout mice. These findings suggest that SPs may offer a promising therapeutic approach for managing bleeding in vWD. In vitro studies on SynthoPlate assessed its impact on thrombin and fibrin generation to evaluate its procoagulant potential. SynthoPlate did not induce spontaneous thrombin generation in human plasma but enhanced fibrin deposition under flow conditions by promoting platelet recruitment and aggregation on a collagen and vWF-coated surface. In vivo, a thrombocytopenic mouse model was used to assess SynthoPlate's hemostatic efficacy. Mice treated with SynthoPlate exhibited significantly reduced bleeding times following tail transection compared to controls, with effects observed within a two-hour circulation period. Immunostaining and immunoblotting confirmed enhanced fibrin formation at the injury site, indicating that SynthoPlate effectively supports clot formation in platelet-deficient conditions.
=== Malaysia === According to the Malaysian Food Act 1983 and Regulations (as of 5 January 2010), ractopamine is allowed in pig muscle and fat (MRL of 10 ppb), pig liver (MRL of 40 ppb), and pig kidney (MRL of 90 ppb). Ractopamine is allowed as its half-life is lower, leading to reduced residues in the food, and the dose required to affect humans is much higher than other beta agonists. On 30 December 2008, the Malaysian Veterinary Services Department quarantined 10 of the 656 pig farms in Malaysia, as the livestock were found to contain the banned chemical.
=== 1 June === Three people, including a mother and her child, were killed in a Russian air attack on Kyiv in the early hours of the day. The victims were from the Desnianskyi District. Reports said that the casualties were trying to access a locked bomb shelter when the attack occurred. Four people were detained in connection to the incident, namely a security guard, the director of a medical facility, his deputy and the first deputy of the district administration. A subsequent audit of Kyiv's bomb shelters found that nearly half of them were unfit for use or closed. Damage was also reported in the Dniprovskyi District. Ten Iskander missiles were intercepted according to the Ukrainian military. In Russia's Belgorod Oblast, eight people were reported to have been injured by Ukrainian shelling in Shebekino. The regional governor, Vyacheslav Gladkov, claimed that Ukrainian forces used Grad rockets. Two others were injured in a drone attack in Belgorod city. The Russian defence ministry claimed it had repulsed three Ukrainian attacks on Belgorod, killed more than 50 Ukrainian soldiers and destroyed four armored vehicles. It said the attacks involved up to 70 "militants", five tanks, four armoured vehicles, seven pick-up trucks and a Kamaz truck. The Ukrainian Ministry of Infrastructure said the Black Sea Grain Initiative had been halted again because Russia had blocked the registration of ships to all Ukrainian ports.
AABB (Association for the Advancement of Blood & Biotherapies) is an international, not-for-profit organization representing individuals and institutions involved in the field of transfusion medicine and biotherapies. The association works collaboratively to advance the field through the development and delivery of standards, accreditation and education programs. AABB is dedicated to its mission of improving lives by making transfusion medicine and biotherapies safe, available and effective worldwide. The association was founded in the United States in 1947 as the American Association of Blood Banks. In 2021, it changed its name to Association for the Advancement of Blood & Biotherapies to better reflect its mission and work. Virtually all blood banks in the United States are accredited by AABB. In addition, AABB accredits hospital transfusion services, biotherapies facilities, cord blood banks, relationship testing facilities, and various other facilities whose work relates to blood and biotherapies. Accreditation by AABB meets the requirements of the Clinical Laboratory Improvement Amendments (CLIA) for blood bank, transfusion service, and immunohematology reference laboratory operations. AABB hosts an annual meeting every fall for the dissemination of research and information for the blood and biotherapies field. The association publishes a monthly magazine, a weekly newsletter, and a peer-reviewed research journal titled Transfusion.
Sources: en.wikipedia.org
The two share the same 29-amino-acid backbone. CJC-1295 carries an additional albumin-binding moiety that markedly extends its residence time in circulation, while the form without that moiety clears faster. Literature sometimes applies the name loosely to either variant.
It has not been approved by major regulatory agencies for any therapeutic indication. Material sold under this name is typically distributed for laboratory research only. Clinical use is not supported by large controlled trials.
Early human studies of the albumin-binding form reported circulation half-lives on the order of several days. The value depends on assay method and study design. Estimates for the form without the binding moiety are considerably shorter.
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.