lyophilization is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-01-22. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic peptide | GHRH analog, not a steroid |
| Backbone length | 29 amino acids | Based on GRF(1-29) |
| Substitutions | Four positions | D-Ala2, Gln8, Ala15, Leu27 |
| Appearance | White to off-white powder | Typical lyophilized research material |
| Common synonyms | Modified GRF(1-29) | Usage varies between sources |
Research material is normally supplied as a freeze-dried powder in sealed vials. In that state the peptide is comparatively robust, but prolonged exposure to warmth, moisture, or light accelerates degradation. Storage at minus twenty degrees Celsius or lower, with desiccant and protection from light, is the commonly described practice. Vials should be allowed to reach room temperature before opening to limit condensation on the powder. Moisture uptake during handling is a recognized source of variability in later measurements.
Reconstitution is typically performed with sterile water or bacteriostatic water, added slowly against the vial wall. The resulting solution should be clear and colorless; cloudiness or visible particles suggest a problem with the material or the diluent. Once in solution, the peptide is less stable than the dry powder. Refrigerated storage at two to eight degrees Celsius is common for short-term holding, while freezing aliquots is described for longer periods.
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.
Identity and purity are established with reversed phase high performance liquid chromatography coupled to mass spectrometry. The chromatographic step separates the target peptide from truncated sequences and deletion products, while the mass measurement confirms the expected molecular weight to within a fraction of a dalton. Because the two common variants differ by the presence of the linker, mass alone can distinguish them in the unconjugated state. Amino acid analysis and peptide mapping are used when sequence level confirmation is required.
Lyophilized material is generally stable for extended periods when held at minus twenty degrees Celsius or below and protected from moisture and light. In solution the peptide is more labile; bond hydrolysis, aggregation and oxidation of susceptible residues all proceed faster at ambient temperature. Repeated freeze and thaw cycles should be avoided because they promote clumping and loss of soluble material. The conjugated variant adds a further consideration, since the maleimide group can hydrolyze in aqueous buffer and lose its ability to react with albumin.
== Research and career == Whilst Wolk enjoyed her career at the Geisinger Health System, she discovered that she was being paid considerably less than her male colleagues. She was told this wage disparity would only be rectified if she returned to college and completed a postgraduate degree, so she joined Wilkes University. Wolk returned to Geisinger, where she led the clinical microbiology laboratory for fourteen years. Wolk returned to university in the mid-nineties to work toward a doctorate at the University of Arizona. She studied medical parasitology, demonstrating that chlorine could be used as an effective water treatment of Encephalitozoon syn. Septata intestinalis. She also demonstrated that spectrophotometric methods could be used for laboratory-based disinfection studies. After earning her doctorate, Wolk moved to the Mayo Clinic, where she completed a fellowship in clinical microbiology. During her fellowship, she developed a polymerase chain reaction (PCR) assay that could detect Encephalitozoon intestinalis in stool samples. Her rapid testing systems were translated out of the research lab, and used for the diagnostics of bacteria in emergency departments. After completing her fellowship, Wolk returned to Arizona, where she was made Director of the Southern Arizona VA Health Care System. There she expanded the programs in clinical microbiology, and established the Infectious Diseases Research Core (IDRC), a Clinical Laboratory Improvement Amendments (CLIA) compliant research laboratory to test novel infectious diseases.
=== Pharmacokinetics === LAAM undergoes extensive first-pass metabolism to the active demethylated metabolite nor-LAAM, which is further demethylated to a second active metabolite, dinor-LAAM. These metabolites are more potent than the parent drug.
=== Pharmacodynamics === DPIA is a norepinephrine transporter inhibitor with an IC₅₀ value of 3.1 µM, as well as a dopamine transporter inhibitor with a potency approximately 13 times weaker than that of amphetamine, but 7 times more potent than amphetamine in inhibiting the serotonin transporter, although, unlike amphetamine, DPIA does not exhibit monoamine-releasing activity. It exhibits moderate affinity for 5-HT1A serotonin receptors (Ki = 3.5 µM) and for alpha-1A-adrenoreceptors (Ki = 0.12 µM), and binds to alpha-2A-adrenoreceptors and TAAR1. In experiments on rodents, DPIA produced the same central effects and toxicity as amphetamine, but was less potent. Interestingly, unlike amphetamine, DPIA caused a reduction in heart rate and blood pressure (exhibiting cardiodepressant properties).
== Avoidance == In theory, avoidance is simply a matter of preventing hyperinsulinemia. In practice, the difficulty for a diabetic person to aggressively dose insulin to keep blood sugars levels close to normal — while adjusting the insulin regimen to the demands of exercise, stress, and wellness — can practically assure occasional hyperinsulinemia. The pharmacokinetic imperfections of all insulin replacement regimens is a severe limitation. Some practical behaviors which are useful in avoiding chronic Somogyi rebound are:
Sources: en.wikipedia.org
== Further reading == Luna C, Estévez M (January 2019). "Formation of allysine in β-lactoglobulin and myofibrillar proteins by glyoxal and methylglyoxal: Impact on water-holding capacity and in vitro digestibility". Food Chemistry. 271: 87–93. doi:10.1016/j.foodchem.2018.07.167. PMID 30236745. S2CID 52309183. Luna C, Arjona A, Dueñas C, Estevez M (March 2021). "Allysine and α-Aminoadipic Acid as Markers of the Glyco-Oxidative Damage to Human Serum Albumin under Pathological Glucose Concentrations". Antioxidants. 10 (3): 474. doi:10.3390/antiox10030474. PMC 8002732. PMID 33802856.
This was intended to discourage white Rhodesians from voting for independence in the referendum, for which the RF campaign slogan was "Yes means Unity, not UDI". Wilson was pleased when Douglas-Home, his leading opponent in the House of Commons, praised the statement as "rough but right". On 5 November 1964, Rhodesia's mostly white electorate voted "yes" to independence under the 1961 constitution by a margin of 89%, prompting Smith to declare that the British condition of acceptability to the people as a whole had been met.
== Function == The mitochondria in a eukaryotic cell utilize fuels to produce adenosine triphosphate (ATP). This process involves storing energy as a proton gradient, also known as the proton motive force (PMF) generated by moving protons from the mitochondrial matrix (N or negative side) across the mitochondrial inner membrane to the mitochondrial intermembrane space (P or positive side) using the energy released by the electron transport chain. This proton gradient energy is used to synthesize ATP when the protons flow across the membrane (down their concentration gradient - from a region of high proton concentration to a region of lower proton concentration) through the ATP synthase complex; this is known as chemiosmosis. In endotherms, body heat is maintained by signaling the mitochondria to allow protons to move back into the mitochondrial matrix (down their concentration gradient - from a region of high proton concentration to a region of lower proton concentration) without producing ATP (proton leak). This can occur since an alternative return route for the protons exists through an uncoupling protein in the inner membrane. This protein, known as uncoupling protein 1 (thermogenin) - which is unique to brown adipose tissue, facilitates the return of the protons after they have been actively pumped out of the mitochondrial matrix by the electron transport chain. This alternative route for protons uncouples oxidative phosphorylation and the energy in the PMF is instead released as heat.
Sources: en.wikipedia.org
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.
The original material included a linker that binds serum albumin. A later variant removed that linker to reduce the duration of action. Catalogs and papers did not consistently adopt separate names, so both remain widely labeled with the same term.
The amino acid sequence and the presence or absence of the linker group. Mass measured by spectrometry gives an independent check that separates the two forms.
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.