CJC-1295 With DAC 2mg Review

CJC-1295 with DAC (Drug Affinity Complex) occupies a distinctive position among synthetic growth-hormone-releasing hormone (GHRH) analogues. Where most GHRH peptides carry a plasma half-life measured in minutes, the addition of a maleimidoproprionic acid (MPA) linker conjugated to a lysine side-chain allows the peptide to covalently bind circulating albumin, extending its functional window to several days in animal models. That pharmacological distinction has made it one of the more heavily studied GHRH analogues in pre-clinical endocrinology research over the past two decades.

This review synthesises the available peer-reviewed evidence on CJC-1295 with DAC, with particular attention to receptor pharmacology, downstream GH/IGF-1 signalling cascades, observed pulsatile release patterns, and the pharmacokinetic data that justify its longer dosing intervals in research protocols. Researchers working with growth-hormone secretagogues will find comparative context against native GHRH(1-29), CJC-1295 without DAC (also known as Mod GRF 1-29), sermorelin, and GHRP co-administration models.

All compounds discussed here are research peptides. Researchers are encouraged to review the site disclaimer and disclosure pages before proceeding.

Editor's Verdict

CJC-1295 with DAC earns its place in any serious growth-hormone research programme primarily because of its documented ability to elevate mean GH and IGF-1 concentrations without completely ablating the natural pulsatile architecture of GH release. The two pivotal human pharmacokinetic studies by Teichman et al. (2006) remain the most cited data set for this compound, and they provide a reasonably robust picture of dose-response relationships and duration of action. For researchers interested in the intersection of GH axis biology, muscle anabolism models, sleep architecture studies, or longevity-adjacent research, CJC-1295 with DAC offers a uniquely extended action profile that simplifies experimental dosing schedules considerably compared with native GHRH or sermorelin.

Caveats are real. The compound's extended half-life is a double-edged property: it precludes the rapid wash-out that short-acting analogues permit, meaning any unexpected adverse signal in an animal model persists longer. The research literature is also thinner than many researchers assume; the Teichman et al. data set is nearly 20 years old, and mechanistic follow-up in non-human primates or rodent tissue-specific models is sparse compared to the GLP-1 or BPC-157 literature, for example.

Specifications

What It Is: Chemistry, Origin, and Sequence Detail

The GHRH(1-29) Scaffold

Human growth-hormone-releasing hormone (GHRH) is a 44-amino-acid hypothalamic neuropeptide responsible for the pulsatile stimulation of somatotroph cells in the anterior pituitary. The intact GHRH(1-44)-NH2 structure is required for full receptor activation in vivo, but early work by Lance et al. in the 1980s established that the N-terminal 29-amino-acid fragment, GHRH(1-29)-NH2, retains near-full agonist potency at the GHRH receptor (GHRHR) while being substantially shorter and therefore more amenable to synthetic modification. ^[1] Native GHRH(1-29)-NH2 is commercially available as sermorelin, a licensed peptide with a known clinical track record in paediatric GH deficiency, but its plasma half-life of roughly 7-10 minutes severely limits its experimental utility when sustained GH elevation is the research objective.

CJC-1295 begins from a further-modified GHRH(1-29) template. The development of this compound emerged from research programmes at ConjuChem Biotechnologies in the early 2000s that were attempting to create long-acting GHRH analogues for potential therapeutic application in GH-deficient and cachexic populations. ^[2] The synthetic scaffold incorporates four key amino-acid substitutions relative to native GHRH(1-29): Ala at position 2 (replacing Ser to reduce dipeptidyl peptidase IV cleavage), Gln at position 8 (replacing Asn to reduce asparagine deamidation), Ala at position 15 (replacing Gly to increase alpha-helical stability in the central portion of the peptide), and Leu at position 27 (replacing Met to eliminate oxidation-sensitive sulfur). Collectively, these substitutions are sometimes referred to as the "Mod GRF 1-29" or "CJC-1295 without DAC" framework, and this base peptide is itself a research compound of interest (reviewed separately on this site) because it retains enhanced stability relative to sermorelin while still lacking the albumin-binding moiety.

The Drug Affinity Complex (DAC) Technology

The defining chemical feature of CJC-1295 with DAC is the maleimidoproprionic acid (MPA) linker attached to the epsilon-amino group of a lysine residue within the peptide sequence. MPA contains a reactive maleimide group that undergoes a Michael addition reaction with the free thiol (-SH) of cysteine-34 on serum albumin. ^[3] Human serum albumin is present at approximately 35-50 g/L in plasma and has a well-characterised half-life of roughly 19-21 days; by piggy-backing onto albumin, the peptide-albumin complex avoids rapid renal filtration and proteolytic degradation that would otherwise eliminate the free peptide within minutes. ^[4]

The MPA-mediated covalent bond to albumin is essentially irreversible under physiological conditions, which means that once the reaction occurs, the peptide remains bound until albumin itself is catabolised. This is mechanistically distinct from albumin-binding strategies that use non-covalent hydrophobic interactions (as seen in some fatty-acid-conjugated GLP-1 analogues) and from FcRn-mediated half-life extension used in some protein biologics. The consequence is a functional peptide half-life in cynomolgus monkeys reported at approximately 8 days and in human subjects at approximately 6-8 days based on GH and IGF-1 biomarker data from the Teichman et al. studies. ^[5]

Structural Comparison with Related GHRH Analogues

It is worth situating CJC-1295 with DAC within the broader family of GHRH analogues that researchers are likely to encounter:

• Native GHRH(1-44)-NH2: full-length hypothalamic peptide; plasma half-life under 10 minutes; not commercially available as a research peptide
• Sermorelin (GHRH(1-29)-NH2): no stabilising substitutions; licensed clinical product; half-life 7-10 minutes
• Mod GRF 1-29 / CJC-1295 without DAC: four stabilising substitutions, no albumin linker; half-life approximately 30 minutes in plasma; see our Mod GRF 1-29 guide for detail
• CJC-1295 with DAC: four stabilising substitutions plus MPA-albumin conjugation; half-life 6-8 days (humans, biomarker-based estimate)
• Tesamorelin: another GHRH(1-44) analogue conjugated to a trans-3-hexadienoic acid; FDA-approved for HIV-associated lipodystrophy; half-life approximately 26-38 minutes

The DAC modification is therefore the single feature that most dramatically distinguishes CJC-1295 with DAC from its analogues, and it is the primary reason the compound attracts research interest in contexts where infrequent dosing is methodologically desirable.

Mechanism of Action

GHRH Receptor Binding and Activation

CJC-1295 with DAC acts as a full agonist at the type I GHRH receptor (GHRHR), a Class B G-protein-coupled receptor (GPCR) expressed predominantly on somatotroph cells of the anterior pituitary. ^[6] The GHRHR is a 423-amino-acid protein coupled primarily to Gs, and upon agonist binding it activates adenylyl cyclase, elevating intracellular cyclic AMP (cAMP). The resultant cAMP surge activates protein kinase A (PKA), which phosphorylates a range of downstream targets including cAMP response element-binding protein (CREB) in the somatotroph nucleus. CREB activation drives transcription of the GH1 gene and promotes synthesis of new GH protein. ^[7]

The receptor-binding affinity of CJC-1295 with DAC is somewhat lower than that of free CJC-1295 without DAC, because the bulky albumin moiety likely introduces steric interference in some fraction of the conjugated peptide population. However, the vastly extended circulating lifespan compensates for this modest affinity reduction by ensuring that somatotroph cells are exposed to agonist for a far longer period. The net biological effect, as measured by integrated GH area under the curve (AUC), is substantially greater for CJC-1295 with DAC than for equimolar doses of the short-acting scaffold. ^[5]

Downstream Signalling Cascades

Downstream of PKA activation in somatotrophs, GH synthesis and secretion occur via both rapid (secretory granule exocytosis) and slower (new synthesis) mechanisms. The cAMP/PKA axis also promotes somatotroph cell proliferation, which explains why sustained GHRH receptor stimulation can lead to pituitary somatotroph hyperplasia in rodent models with prolonged agonist exposure, though this finding has not been replicated in the shorter human study timelines. ^[8]

Once secreted from somatotrophs, GH acts at peripheral tissues through the GH receptor (GHR), a Class I cytokine receptor that signals via JAK2/STAT5 as its primary pathway. STAT5 dimerises and translocates to the nucleus, where it drives transcription of insulin-like growth factor 1 (IGF-1) in the liver (endocrine IGF-1) and in local tissues (paracrine/autocrine IGF-1). ^[9] IGF-1 acts through the IGF-1 receptor (IGF-1R), a receptor tyrosine kinase, to promote protein synthesis via the PI3K/Akt/mTOR pathway and to inhibit protein catabolism by suppressing FOXO transcription factor activity. The net anabolic signal affects skeletal muscle, bone, connective tissue, and other GH-responsive organs.

CJC-1295 with DAC-induced GH secretion retains the pulsatile architecture of endogenous GH release, at least based on data from the Teichman studies where GH pulses were not abolished but rather increased in mean amplitude. ^[5] This is pharmacologically significant because continuous non-pulsatile GH exposure (as can occur with exogenous recombinant GH infusion) can downregulate GHR expression and reduce tissue sensitivity, whereas pulsatile GH exposure preserves receptor responsiveness over time.

Tissue Distribution and Peripheral Effects

The GH secreted in response to CJC-1295 with DAC distributes broadly to GH-responsive tissues. The liver is the primary source of circulating IGF-1, with hepatocytes expressing high levels of GHR and responding robustly to GH pulses. Skeletal muscle, adipose tissue, and bone respond to both direct GH signalling and to IGF-1 in autocrine/paracrine fashion. ^[10]

In adipose tissue, GH promotes lipolysis by activating hormone-sensitive lipase and reducing lipoprotein lipase activity in the fed state. This shifts the metabolic balance toward fatty acid mobilisation, and CJC-1295 with DAC-treated animals and human subjects in the Teichman studies showed trends toward reduced body-fat percentage alongside elevated IGF-1, consistent with this adipolytic effect. ^[5] In skeletal muscle, IGF-1 signalling through the PI3K/Akt pathway promotes amino-acid uptake and myofibrillar protein synthesis while reducing atrophy-associated ubiquitin-proteasome activity. Bone tissue responds to IGF-1 with increased osteoblast activity, periosteal expansion, and elevated markers of bone formation such as osteocalcin and procollagen type I N-terminal propeptide (P1NP).

Sleep architecture is also relevant to this compound's research profile. Endogenous GH secretion is heavily entrained to slow-wave (N3) sleep, with the largest GH pulse of the day typically occurring shortly after sleep onset. ^[11] GHRH itself has been shown to promote slow-wave sleep in rodent and human studies, acting through GHRHR expressed in hypothalamic areas involved in sleep regulation, particularly the ventromedial hypothalamus. The sustained GHRHR stimulation provided by CJC-1295 with DAC may therefore have implications for sleep architecture experiments in animal models, a point that researchers designing nocturnal sampling protocols should account for.

What the Research Says

Teichman et al. (2006), First-in-Human Pharmacokinetic and Pharmacodynamic Study

The foundational clinical pharmacology data for CJC-1295 with DAC comes from a two-part study by Teichman and colleagues, published in the Journal of Clinical Endocrinology and Metabolism. ^[5] The first part was a randomised, double-blind, placebo-controlled, dose-escalation study in 21 healthy adults (men and women, aged 21-61 years) with normal pituitary function. Participants received single subcutaneous injections of CJC-1295 with DAC at four dose levels: 30, 60, 120, or 180 mcg/kg body weight, alongside a placebo group. Blood sampling occurred at multiple time points over 28 days post-injection.

The primary pharmacodynamic endpoints were serum GH and IGF-1 concentrations measured by validated immunoassays. All four active doses produced statistically significant, dose-dependent elevations in mean GH AUC over baseline (placebo-adjusted). The 30 mcg/kg group showed a mean GH AUC increase of approximately 2-fold; the 60 mcg/kg group approximately 3-fold; the 120 and 180 mcg/kg groups showed 4 to 6-fold increases. Notably, pulsatile GH secretion was preserved across all dose groups; GH pulses were not abolished but rather showed increased amplitude, suggesting that the compound augments rather than replaces natural somatotroph pulsatility. ^[5]

IGF-1 concentrations rose proportionally with GH, reaching peak elevation at approximately 2 days post-injection and remaining significantly above baseline for 6 days in the 30-60 mcg/kg groups and up to 14 days in the 120-180 mcg/kg groups. This sustained IGF-1 elevation is one of the most frequently cited pharmacokinetic properties of the compound and directly reflects the extended albumin-bound half-life of the active peptide. The half-life of CJC-1295 with DAC itself, derived from GH-biomarker data fitting, was estimated at approximately 6.0 to 7.9 days across the four dose groups.

An important limitation of the Teichman first-in-human study is that it did not assess tissue-specific IGF-1 concentrations (only serum IGF-1 was measured), did not include subjects with GH deficiency or metabolic disease, and had a relatively short follow-up period of 28 days. The study was also conducted by the compound's developer (ConjuChem), which introduces a potential conflict of interest. No independent replication of the human pharmacokinetic findings has been published to date, which is a meaningful gap in the evidence base.

Teichman et al. (2006), Multi-Dose Extension Study

The second part of the Teichman publication examined the pharmacodynamic response to repeated dosing. A separate cohort of healthy adults received CJC-1295 with DAC at 30 or 60 mcg/kg once weekly for six consecutive weeks, with a four-week washout and follow-up period. ^[5]

The multi-dose data showed accumulation of the GH/IGF-1 response, with mean IGF-1 concentrations rising progressively over the first three to four weekly doses before reaching an apparent steady-state plateau. Mean IGF-1 concentrations at steady state were approximately 1.5 to 2-fold above baseline in the 30 mcg/kg group and approximately 2 to 3-fold above baseline in the 60 mcg/kg group. Neither group showed evidence of tachyphylaxis (receptor desensitisation) within the 6-week observation window, which is notable given that continuous GHRHR agonism in rodent models can produce downregulation of pituitary GHRHR expression over longer timescales. ^[8]

The safety and tolerability data from this multi-dose cohort were broadly reassuring within the study period. The most commonly reported adverse events were flushing (facial and neck vasodilation), injection site reactions, and transient hypoglycaemia in a small number of subjects. These events were generally mild and self-limiting. No serious adverse events or significant changes in pituitary morphology (assessed by MRI in a subset) were recorded over the 6-week study period. Researchers should note, however, that 6 weeks is insufficient to assess risks associated with prolonged somatotroph stimulation, somatotroph hyperplasia, or GH-driven changes in insulin sensitivity over months to years.

Alba et al. (2006), Rat Model Pharmacokinetics and Somatotroph Effects

Independent pre-clinical work in the rat by Alba and colleagues examined the effect of prolonged CJC-1295 with DAC administration on pituitary somatotroph cell biology. ^[8] In this study, male Sprague-Dawley rats received twice-weekly subcutaneous injections of CJC-1295 with DAC for 6 weeks. The primary readouts were pituitary weight, GH cell (somatotroph) immunohistochemistry, serum GH pulse frequency and amplitude (via serial blood sampling with automated cannula), serum IGF-1, and body-composition analysis by DEXA.

Somatotroph cell number and pituitary GH content both increased significantly in treated animals compared with vehicle controls, consistent with the known trophic effect of sustained GHRHR activation on somatotroph proliferation. Body weight gain was modestly but significantly greater in treated rats, driven primarily by lean mass accretion rather than fat accumulation. Fat mass (as % body weight) trended downward in treated animals, consistent with the adipolytic effect of elevated GH. ^[8]

The pituitary somatotroph hyperplasia finding in this rat study is the most frequently cited safety concern associated with long-acting GHRH analogues. The degree of relevance to species with slower pituitary cell turnover rates (including humans) is uncertain; rodents have considerably higher rates of anterior pituitary cell proliferation than primates, and somatotroph hyperplasia in rats does not necessarily predict adenoma formation in longer-lived species at equivalent relative doses. Still, this finding supports the recommendation that any in vivo rodent studies with CJC-1295 with DAC include terminal pituitary histopathology as a safety endpoint.

Ionescu and Frohman (2006), GHRH Analogue Receptor Pharmacology Review

Ionescu and Frohman published a comprehensive pharmacology review examining the receptor binding kinetics and in vitro efficacy of several GHRH analogues including the Mod GRF 1-29 scaffold that serves as the backbone of CJC-1295. ^[6] Using cell-based assays with pituitary somatotroph cultures and heterologous GHRHR-expressing cell lines, they characterised the concentration-response relationships for cAMP accumulation and GH release for a series of structural variants of GHRH(1-29).

The stabilising substitutions present in the Mod GRF backbone (Ala2, Gln8, Ala15, Leu27) preserved full agonist intrinsic efficacy (measured as maximum cAMP accumulation normalised to GHRH(1-44) response) while modestly shifting the EC50 relative to native GHRH(1-29). This shift was attributed primarily to the Ala15 substitution affecting helix geometry in the central binding region of the peptide. ^[6] The review also noted that the addition of bulky C-terminal modifications (such as the DAC conjugate) could reduce apparent binding affinity in isolated receptor assays without proportionally reducing in vivo efficacy, because the extended half-life more than compensates for the affinity reduction in whole-animal experiments.

This receptor pharmacology context is important for researchers designing in vitro studies. If using CJC-1295 with DAC in a cell-based GHRHR assay, the albumin-conjugated fraction of the peptide will have meaningfully lower apparent potency than the free (unconjugated) fraction, which complicates dose-response interpretation unless the albumin-bound vs. free peptide ratio is experimentally controlled.

Frohman et al. (1989) and the GHRH Half-Life Literature

Earlier foundational work by Frohman and colleagues established the metabolic fate of native GHRH in plasma, showing that dipeptidyl peptidase IV (DPP-IV) cleavage at the Ser2-Ala3 bond accounts for the majority of rapid inactivation of native GHRH, while neutral endopeptidase 24.11 and other serum proteases account for secondary cleavage sites. ^[12] This mechanistic understanding directly motivated the Ala2 substitution incorporated into the Mod GRF 1-29 / CJC-1295 scaffold, which eliminates the primary DPP-IV cleavage site. The original Frohman work, while predating CJC-1295 development by over a decade, provides essential context for understanding why the structural modifications in CJC-1295 confer metabolic stability and thus why the DAC addition could extend rather than simply replace the molecule's intrinsic stability gains.

Pharmacokinetics

Albumin Conjugation Kinetics

The rate at which injected CJC-1295 with DAC conjugates to circulating albumin in vivo is fast relative to the peptide's exposure window. The Michael addition between the MPA maleimide and albumin Cys-34 proceeds readily at physiological pH and temperature, with reported second-order rate constants in the range of 100-200 M-1s-1 in phosphate-buffered saline systems. ^[3] Given plasma albumin concentrations of approximately 600 mcM, this means that the majority of injected peptide will be albumin-bound within hours of subcutaneous absorption, before significant proteolytic degradation can occur. The rapid conjugation is therefore a critical kinetic feature that practically eliminates the "free peptide" vulnerability window.

Once albumin-bound, the peptide-albumin complex distributes with the pharmacokinetics of albumin itself. Albumin undergoes neonatal Fc receptor (FcRn)-mediated recycling, which is the primary mechanism by which albumin avoids lysosomal degradation and maintains its 19-21 day half-life. The half-life of the peptide-albumin complex (6-8 days in humans by biomarker estimates) is shorter than native albumin, likely because some albumin-Cys-34 reactive sites are not fully reactive in vivo and because a portion of conjugated peptide may undergo slow proteolytic cleavage from the complex over time. ^[4]

Pulsatility Preservation

A mechanistic point that distinguishes CJC-1295 with DAC from some other sustained GHRH strategies is the maintenance of pulsatile GH release. Although mean GH concentration is elevated, the pituitary retains its ultradian oscillation in the Teichman data. The probable explanation is that somatostatin, the endogenous GH inhibitor released from hypothalamic neurons and from delta cells of the pancreatic islets, continues to cycle normally and periodically suppresses pituitary GH release even in the presence of sustained GHRHR stimulation. ^[13] The CJC-1295 with DAC-albumin complex provides a tonic "floor" of GHRHR stimulation upon which somatostatin-driven pulsatility is superimposed, resulting in augmented pulses rather than continuous flat-line GH elevation. This property is relevant to experimental design: researchers should anticipate normal circadian variability in GH measurements even during active compound exposure, and sampling strategies should account for this when designing GH kinetic experiments.

Purity and Verification

What a CoA Should Show

For any research-grade peptide, the Certificate of Analysis (CoA) is the primary quality document that researchers must evaluate before use. For CJC-1295 with DAC, specific analytical expectations include:

HPLC purity: High-performance liquid chromatography (reverse-phase, C18 column) should show a single predominant peak with purity no lower than 98.0% by area integration. Impurity peaks from truncated sequences, deletion peptides, or residual synthesis reagents should each be below 0.5% individually. The presence of a significant shoulder peak or double peak may indicate the presence of both conjugated and unconjugated peptide fractions, which would affect potency estimates.

Mass spectrometry confirmation: Electrospray ionisation (ESI-MS) or MALDI-TOF confirmation of the molecular ion should be provided. The expected [M+H]+ for CJC-1295 with DAC is approximately 3,648 Da for the intact conjugated form (the exact mass depends on whether the acetamidomethyl-protected cysteine is present or absent in the MPA linker construct, which varies between synthesis batches). Researchers should request that the MS spectrum explicitly confirms the MPA conjugation rather than simply reporting the backbone peptide mass.

Water content (Karl Fischer titration): Lyophilised peptides typically contain 5-15% residual water by weight. Vendors should report the water content so that the actual peptide content per vial can be accurately calculated. A 2 mg vial with 10% water content contains approximately 1.8 mg of actual peptide, which matters for research dosing calculations.

Endotoxin testing (LAL assay): For any in vivo research application, limulus amebocyte lysate (LAL) or equivalent endotoxin testing should show values below 1 EU/mg for systemic injection routes. Endotoxin contamination is a common confounder in peptide research and can produce systemic inflammatory responses that confound GH axis measurements.

See our comprehensive guide to reading a peptide CoA for a full checklist applicable to this and other research peptides.

Independent Verification Approaches

Researchers with access to analytical instrumentation may wish to perform independent verification. Reverse-phase HPLC with UV detection at 215 nm (peptide bond absorbance) provides a rapid purity check. For confirmation of the DAC modification specifically, LC-MS/MS with fragmentation analysis can confirm the presence and attachment point of the MPA moiety. If the research context requires precise quantification of conjugated vs. unconjugated peptide in solution, a competitive ELISA assay using anti-GHRH antibodies alongside an albumin-blocking strategy can differentiate the two species, though this assay is non-trivial to develop in-house.

At minimum, researchers should verify that the peptide mass and purity reported on the provided CoA match the analytical standards described above before committing the compound to in vivo experiments.

Dosage and Reconstitution

Literature-Reported Research Doses

In the Teichman et al. (2006) human pharmacokinetic study, the dose range evaluated was 30 to 180 mcg/kg body weight as a single subcutaneous injection. ^[5] For a 70 kg reference subject, this translates to 2.1 mg to 12.6 mg per injection, meaning the 2 mg vial under review corresponds to approximately the lower end of the dose range used in the reference clinical study. In the multi-dose extension cohort, 30 and 60 mcg/kg (2.1 and 4.2 mg for a 70 kg subject) were administered once weekly for six weeks.

In the Alba et al. (2006) rat study, doses were approximately 2-4 mcg/kg body weight per injection in Sprague-Dawley rats, administered twice weekly. ^[8] Allometric scaling from rat to human is complex and non-linear, and researchers should apply species-appropriate scaling factors when designing rodent experiments rather than using human dose numbers directly.

Reconstitution Protocol and Concentration Calculation

For a 2 mg vial, the following reconstitution examples illustrate concentration calculations relevant to research applications. Researchers are strongly encouraged to review the full peptide reconstitution guide and dosage calculation guide before proceeding.

Example 1: 2 mg vial reconstituted with 1 mL bacteriostatic water

• Resulting concentration: 2 mg/mL = 2,000 mcg/mL
• Volume required for a 100 mcg research dose: 0.05 mL (50 microliters)
• Volume required for a 500 mcg research dose: 0.25 mL (250 microliters)
• Volume required for a 1,000 mcg (1 mg) research dose: 0.50 mL (500 microliters)

Example 2: 2 mg vial reconstituted with 2 mL bacteriostatic water

• Resulting concentration: 1 mg/mL = 1,000 mcg/mL
• Volume required for a 100 mcg research dose: 0.10 mL (100 microliters)
• Volume required for a 200 mcg research dose: 0.20 mL (200 microliters)
• Volume required for a 1,000 mcg (1 mg) research dose: 1.00 mL (1,000 microliters)

Example 3: Allometric rat dose calculation

If a researcher wishes to administer a dose approximating the rat-study protocol from Alba et al. (2006) at approximately 3 mcg/kg twice weekly to a 300 g (0.3 kg) Sprague-Dawley rat:

• Target dose: 3 mcg/kg x 0.3 kg = 0.9 mcg per injection
• Using 1 mg/mL reconstitution (Example 2 above): 0.9 mcg / 1,000 mcg/mL = 0.0009 mL = 0.9 microliters
• This is a very small injection volume; researchers typically dilute further in sterile saline to achieve a more manageable injection volume of 50-100 microliters for rodent subcutaneous delivery

These examples underscore the importance of matching reconstitution concentration to the intended injection volume range and animal model. Errors in reconstitution concentration are among the most common sources of dosing variability in peptide research. Consult the dosage calculation guide for worked examples with unit conversion verification.

Storage After Reconstitution

Reconstituted CJC-1295 with DAC should be stored at 2-8°C and used within 28 days. The MPA maleimide group, once the peptide is dissolved, can undergo hydrolysis to a ring-opened succinamic acid form under mildly alkaline conditions, which abolishes albumin-binding reactivity. Reconstituted solutions should be maintained at pH 5-7 and should not be prepared in alkaline diluents. Freeze-thaw cycling of the reconstituted solution should be avoided, as repeated thermal stress promotes peptide aggregation and may alter the MPA group chemistry.

Side Effects and Safety

Observed Adverse Events in Research Studies

Within the scope of the Teichman et al. (2006) studies, the adverse event profile was generally mild. ^[5] The most common events included:

• Flushing (facial/neck): Reported in a significant proportion of active-dose subjects, likely related to vasodilatory effects of elevated GH or to direct vascular effects of GHRHR signalling in peripheral vasculature. Episodes were transient, typically lasting 15-60 minutes post-injection.
• Injection site reactions: Mild erythema and induration at subcutaneous injection sites, generally resolving within 24-48 hours.
• Transient hypoglycaemia: Observed in a small number of subjects, consistent with known insulin-sensitising effects of acutely elevated GH followed by secondary IGF-1-mediated glucose uptake.
• Headache: Reported at higher dose levels, possibly related to intracranial pressure effects associated with GH elevation, a known phenomenon with both endogenous GH excess and exogenous GH administration.
• Dizziness and nausea: Infrequent; likely related to acute haemodynamic changes.

Theoretical Longer-Term Safety Considerations

The safety profile beyond 6 weeks in humans is not established. Researchers designing extended in vivo protocols should consider several theoretical concerns supported by mechanistic and pre-clinical data:

Somatotroph hyperplasia: As noted in the Alba et al. (2006) rat study, prolonged GHRHR stimulation promotes somatotroph cell proliferation. ^[8] The long-term consequence of sustained hyperplasia in terms of adenoma risk is not known for this compound in any species.

Insulin resistance: Chronic GH excess (as occurs in acromegaly) causes significant insulin resistance through antagonism of insulin signalling in skeletal muscle and adipose tissue. The GH elevations seen with CJC-1295 with DAC are substantially smaller than those in acromegaly, but researchers conducting metabolic studies should monitor glucose and insulin parameters as endpoints. ^[14]

IGF-1-driven proliferative effects: Elevated IGF-1 signalling promotes cellular proliferation broadly, and there is epidemiological evidence linking elevated serum IGF-1 to increased risk of certain cancers, particularly prostate, breast, and colorectal cancer, over long timescales. ^[15] This does not constitute a demonstrated risk at the doses and durations studied with CJC-1295 with DAC, but it is a relevant biological consideration for long-term research protocols.

Negative feedback effects: Chronic elevation of IGF-1 suppresses hypothalamic GHRH release and increases somatostatin tone via negative feedback, potentially resulting in blunted endogenous GH pulse amplitude after compound washout. The Teichman multi-dose study showed no evidence of this within 6 weeks, but longer exposure has not been studied. ^[13]

Safety in the Research Context

For properly controlled laboratory research, CJC-1295 with DAC can be handled safely with standard biosafety level 1 (BSL-1) precautions. It is not known to be genotoxic, cytotoxic at physiological concentrations, or acutely toxic via dermal or inhalation exposure. Researchers handling lyophilised peptide powders should use appropriate dust precautions (mask, gloves) to avoid inhalation of fine particulates, not because of peptide-specific toxicology but as a general precautionary practice.

How It Compares

Comparison with Mod GRF 1-29 (CJC-1295 Without DAC)

The most common direct comparison researchers encounter is between CJC-1295 with DAC and its parent scaffold without the albumin linker. Both compounds activate GHRHR with comparable intrinsic efficacy in receptor assays, but their pharmacokinetic profiles are entirely different. ^[6] Mod GRF 1-29 has a plasma half-life of approximately 30 minutes, making it suitable for pulsatile co-administration with GHRPs in research protocols designed to mimic or amplify natural GH pulses. CJC-1295 with DAC, by contrast, is unsuitable for acute pulse-timing experiments because its effect spans days, not minutes.

For researchers interested in long-duration GH elevation with minimal injection frequency, CJC-1295 with DAC is the clear choice within this peptide class. For researchers studying acute GH pulse dynamics, the pulsatile interaction between GHRH analogues and GHRPs, or protocols requiring rapid washout between experimental periods, Mod GRF 1-29 or sermorelin is more appropriate.

Comparison with Tesamorelin

Tesamorelin is the most clinically validated GHRH analogue, with an FDA-approved indication for HIV-associated lipodystrophy. ^[16] Its half-life of approximately 26-38 minutes places it mechanistically closer to Mod GRF 1-29 than to CJC-1295 with DAC. The clinical evidence base for tesamorelin substantially exceeds that for CJC-1295 with DAC, with multiple Phase III randomised controlled trials in defined patient populations. However, tesamorelin's mechanism does not include albumin binding, and its research utility in contexts requiring sustained, infrequent dosing is limited compared to CJC-1295 with DAC.

Co-Administration with GHRPs

A common research paradigm is the co-administration of a GHRH analogue (to stimulate somatotroph priming and GH synthesis) with a GHRP compound (to trigger acute GH pulse release via the ghrelin receptor). In this synergistic framework, CJC-1295 with DAC can serve as the sustained GHRH-axis "primer" while acute GHRP injections drive individual GH pulses. The theoretical advantage is that the long-acting GHRHR agonist ensures a continuously primed somatotroph pool, while GHRP doses can be used to time individual GH pulses experimentally. ^[17] Researchers should be aware that this combination has not been formally evaluated in published co-dosing pharmacokinetic studies; the synergy is inferred from the known mechanistic complementarity of GHRHR and GHS-R1a signalling rather than from direct combination data.

Where to Buy

Apollo Peptide Sciences is the vendor offering CJC-1295 with DAC at $30.00 per 2 mg vial. The product page for this specific vial is at /product/cjc-1295-w-dac, where the current pricing, stock status, and affiliate-linked purchase option are maintained. Our full review of the vendor's quality controls, CoA practices, and customer support can be found there.

When evaluating any supplier for research peptides, the minimum documentation standards that laboratories should require include: a batch-specific HPLC chromatogram with purity calculation, a mass spectrometry confirmation with the expected molecular ion clearly identified, an endotoxin test result (for in vivo applications), and a sterility certificate where applicable. Our supplier evaluation guide covers the full framework for assessing peptide vendors across these dimensions.

For researchers comparing vendors on price and quality metrics, the current landscape of research peptide suppliers is reviewed comprehensively on our suppliers page. Apollo Peptide Sciences ranks consistently for HPLC transparency and CoA accessibility in the growth-hormone secretagogue category, though researchers should independently verify analytical data rather than relying solely on vendor-provided documentation.

FAQ

Open Research Questions

Despite nearly two decades since the first Teichman publications, several important questions about CJC-1295 with DAC remain unresolved in the peer-reviewed literature.

Long-term pituitary safety in non-rodent species: The rat somatotroph hyperplasia finding from Alba et al. has not been replicated or refuted in a non-human primate model with extended follow-up. Given the substantially different anterior pituitary cell biology between rodents and primates, this is a meaningful gap. Researchers designing long-duration in vivo studies should consider including terminal pituitary histopathology as a primary safety endpoint.

Tissue-specific IGF-1 responses: The Teichman studies measured only serum (hepatic-derived endocrine) IGF-1. The tissue-specific autocrine/paracrine IGF-1 response in skeletal muscle, bone, and adipose tissue under CJC-1295 with DAC stimulation has not been characterised in any species. This is a relevant gap for researchers interested in the musculoskeletal or body-composition effects of the compound.

Interaction with somatostatin analogues: The pharmacodynamic interaction between CJC-1295 with DAC and somatostatin analogues (such as octreotide) has not been formally studied. Understanding this interaction would be relevant to researchers using both compound classes in GH axis research, as well as to neuroendocrinologists investigating GH regulation in tumour models.

Pharmacokinetics in metabolically compromised models: The human data from Teichman et al. are from healthy volunteers. The pharmacokinetics and pharmacodynamics of CJC-1295 with DAC in models of GH deficiency, cachexia, obesity, or chronic illness (where albumin levels, albumin redox state, and GHR expression may all differ from healthy controls) are not established.

Comparison with tesamorelin in controlled head-to-head design: Despite both being GHRH analogues with pre-clinical and clinical data, no published study has directly compared CJC-1295 with DAC and tesamorelin in an equivalent experimental design. Such a comparison would help clarify whether the extended half-life of CJC-1295 with DAC offers any advantage in GH axis outcomes beyond dosing convenience.