What is CJC-1295?

CJC-1295 is a synthetic 30-amino-acid peptide analog of growth hormone-releasing hormone (GHRH), developed by ConjuChem Biotechnologies. It is based on the first 29 amino acids of human GHRH — known as GRF(1-29) or sermorelin — with four amino acid substitutions (Ala2→D-Ala, Asn8→Gln, Ala15→Ala, Met27→Leu) that confer resistance to enzymatic degradation by dipeptidyl peptidase-IV (DPP-IV).

The compound exists in two forms: CJC-1295 with DAC (Drug Affinity Complex), which uses a maleimidopropionic acid-lysine linker to covalently bind serum albumin in vivo, and CJC-1295 without DAC (also called modified GRF 1-29 or Mod GRF 1-29), which lacks this albumin-binding moiety. The DAC technology extends the peptide’s circulating half-life from approximately 30 minutes to 6-8 days, enabling weekly rather than multiple-daily dosing.

CJC-1295 with DAC reached Phase II clinical trials (NCT00267527) for HIV-associated visceral obesity but was discontinued. It is not FDA-approved for any indication. UMLS CUI: C1570976; MeSH: C502076.

Mechanism of Action

CJC-1295’s mechanism follows the canonical GHRH signaling cascade in anterior pituitary somatotrophs:

GHRH receptor activation: CJC-1295 binds to GHRH-R, a class B1 G protein-coupled receptor on pituitary somatotroph cells. This triggers the following intracellular cascade:

1. Gs protein coupling — GHRH-R activates the stimulatory Gs-alpha subunit
2. Adenylyl cyclase activation — Gs-alpha stimulates adenylyl cyclase, increasing intracellular cyclic AMP (cAMP)
3. PKA activation — cAMP activates protein kinase A (PKA)
4. CREB phosphorylation — PKA phosphorylates cAMP response element-binding protein (CREB)
5. GH gene transcription — Phospho-CREB binds CRE elements on the GH1 promoter, upregulating GH mRNA synthesis
6. Calcium influx and exocytosis — cAMP also opens L-type voltage-gated calcium channels, triggering GH vesicle release

Downstream GH/IGF-1 axis: Released GH enters systemic circulation and binds hepatic GH receptors, activating the JAK2 → STAT5b signaling cascade. STAT5b translocates to the nucleus and drives IGF-1 gene transcription. Circulating IGF-1 is bound to IGF binding proteins (primarily IGFBP-3 and the acid-labile subunit, ALS), which extend its half-life and regulate bioavailability. IGF-1 acts through the IGF-1 receptor (a tyrosine kinase) to activate PI3K/Akt and Ras/MAPK pathways, promoting cell proliferation, protein synthesis, and anti-apoptotic signaling.

Negative feedback: IGF-1 feeds back to suppress GH at two levels — (1) directly on somatotrophs by disrupting the POU1F1/CBP complex required for GH gene expression, and (2) at the hypothalamus by stimulating somatostatin release, which inhibits further GHRH-mediated GH secretion.

Pulsatility preservation: A critical finding from the Alba et al. (2006, PMID: 17018654) study is that CJC-1295 increases trough GH, mean GH, and pulsatile GH secretion while preserving the episodic release pattern. This distinguishes it from exogenous recombinant GH administration, which suppresses endogenous GH pulses and hypothalamic-pituitary feedback.

DAC (Drug Affinity Complex) Technology

The DAC variant of CJC-1295 represents a bioconjugation strategy developed by ConjuChem to extend peptide half-life without PEGylation:

How it works: A reactive maleimidopropionic acid group is attached to a lysine residue on the GRF(1-29) peptide via a chemical linker. After subcutaneous injection, this maleimide group reacts with the free thiol on Cys34 of circulating serum albumin, forming a stable thioether bond. The resulting peptide-albumin conjugate (~67 kDa complex) is too large for renal filtration and is protected from proteolytic degradation.

Pharmacokinetic comparison:

Property	CJC-1295 without DAC (Mod GRF 1-29)	CJC-1295 with DAC
Half-life	~30 minutes	6-8 days
Dosing frequency	2-3x daily	Weekly
GH pulse pattern	Sharp, discrete pulses	Sustained elevation with preserved pulsatility
Peak GH	Higher acute peaks	Lower but prolonged elevation
IGF-1 duration	Hours	9-11 days of elevation
Albumin binding	No	Yes (covalent thioether bond)

The without-DAC form (Mod GRF 1-29) produces more physiological, sharp GH pulses due to its short half-life, while the DAC variant provides sustained baseline GH elevation. This pharmacokinetic distinction drives different clinical use rationales.

CJC-1295 + Ipamorelin Stack

The combination of CJC-1295 (a GHRH agonist) with ipamorelin (a ghrelin receptor/GHSR agonist) is one of the most studied peptide stacks for GH optimization. The rationale is based on complementary receptor mechanisms:

CJC-1295 (GHRH-R pathway): Activates Gs → cAMP → PKA → GH transcription and secretion. Increases the number of somatotroph cells primed for GH release.

Ipamorelin (GHSR pathway): Activates Gq → phospholipase C → IP3 → intracellular calcium release → GH vesicle exocytosis. Simultaneously suppresses somatostatin release from the hypothalamus, removing the endogenous “brake” on GH secretion.

Synergistic amplification: When both receptors are activated simultaneously, the cAMP pathway (GHRH-R) and the calcium/IP3 pathway (GHSR) converge on GH secretory vesicle exocytosis through parallel mechanisms. Published data show co-administration produces GH responses 2-4 times greater than either compound alone at equivalent doses.

Selectivity advantage: Ipamorelin is notably selective for GH release without significantly increasing cortisol, prolactin, or ACTH — unlike older GH secretagogues such as GHRP-6 or hexarelin. This selectivity, combined with CJC-1295’s sustained GHRH-R activation, provides amplified GH pulsatility with a cleaner hormonal profile.

Clinical Evidence

Human Studies

Teichman et al. (2006, PMID: 16352683): Dose-escalation study in 21 healthy adults receiving single subcutaneous injections of CJC-1295 with DAC at 30, 60, or 120 mcg/kg. Results showed dose-dependent increases in mean plasma GH concentrations of 2- to 10-fold above baseline, sustained for 6 or more days. Mean plasma IGF-1 increased 1.5- to 3-fold, persisting for 9-11 days. The compound was described as “safe and relatively well tolerated, particularly at doses of 30 or 60 mcg/kg.”

Alba et al. (2006, PMID: 17018654): Confirmed that GH pulsatility was preserved during continuous CJC-1295 stimulation. Trough GH, mean GH secretion, and pulsatile GH secretion all increased without loss of the episodic release pattern. This was a critical finding, as loss of pulsatility would reduce the physiological effectiveness of GH signaling at target tissues.

Phase II trial — HIV visceral obesity (NCT00267527): ConjuChem sponsored a multicenter, randomized, placebo-controlled, double-blind Phase II trial in 120 HIV-positive adults with visceral obesity (BMI 24-30). Participants received CJC-1295 at two dose levels versus placebo for 12 weeks. The trial was terminated in 2006.

Preclinical Studies

Jette et al. (2005, PMID: 15817669): Established the DAC-albumin bioconjugation mechanism in rats, demonstrating that hGRF(1-29)-albumin bioconjugates activate the GRF receptor on the anterior pituitary and identified CJC-1295 as a long-lasting GRF analog.

Ionescu et al. (2006, PMID: 16822960): Demonstrated that once-daily CJC-1295 administration normalized growth in GHRH knockout mice, providing proof-of-concept for the long-acting GHRH agonist approach.

Molecular Properties

Property	Value
Peptide class	GHRH analog (modified GRF 1-29)
Amino acid length	30 (29 + C-terminal amide)
Key modifications	D-Ala2, Gln8, Ala15, Leu27
UMLS CUI	C1570976
MeSH ID	C502076
Half-life (without DAC)	~30 minutes
Half-life (with DAC)	6-8 days
DAC mechanism	Maleimide → Cys34 albumin thioether bond
Developer	ConjuChem Biotechnologies
Highest clinical phase	Phase II (terminated)

Blood Marker Effects

CJC-1295 administration produces measurable changes in several blood biomarkers:

GH/IGF-1 axis:

• Growth hormone: 2- to 10-fold elevation (dose-dependent, sustained 6+ days with DAC)
• IGF-1: 1.5- to 3-fold elevation (sustained 9-11 days with DAC)
• IGFBP-3: Expected elevation proportional to IGF-1 increases

Glucose and insulin metabolism:

• Sustained GH elevation is known to promote insulin resistance by antagonizing insulin signaling in liver and skeletal muscle
• Fasting glucose may increase with chronic GH elevation
• Patients with prediabetes or diabetes should be monitored closely if using GH secretagogues

Thyroid axis considerations:

• GH increases hepatic T4-to-T3 conversion via stimulation of type 1 deiodinase
• Subclinical hypothyroidism may be unmasked by GH therapy, as increased T4-to-T3 conversion depletes T4 stores
• Thyroid function monitoring is recommended during GH-axis stimulation

Cortisol and prolactin:

• CJC-1295 alone does not significantly alter cortisol or prolactin levels
• This distinguishes GHRH analogs from some GH secretagogues (e.g., GHRP-6) that cross-stimulate ACTH or prolactin release

Drug Interactions & Contraindications

Contraindications:

• Active malignancy or history of cancer — GH/IGF-1 axis activation may promote tumor growth
• Pregnancy and breastfeeding — no human safety data
• Uncontrolled diabetes — GH antagonizes insulin signaling
• Active pituitary pathology — may exacerbate underlying dysfunction

Potential interactions:

• Corticosteroids — may attenuate GH response and alter glucose metabolism
• Thyroid medications — GH-mediated T4→T3 conversion may require levothyroxine dose adjustment
• Insulin and oral hypoglycemics — GH-induced insulin resistance may alter glycemic control
• Other hormone therapies — testosterone, estrogen, and other hormones interact with the GH/IGF-1 axis

Regulatory status: CJC-1295 is not FDA-approved for any therapeutic indication. The FDA has raised safety concerns regarding compounded peptide products containing CJC-1295. It is banned by WADA in competitive sports.

Safety & Side Effects

In the Teichman et al. dose-escalation study, CJC-1295 was described as “safe and relatively well tolerated” at doses of 30-60 mcg/kg. The most commonly reported adverse effects across published clinical data and post-market surveillance include:

• Injection site reactions — pain, erythema, swelling, and induration at the injection site
• Facial flushing — transient warmth and redness, typically resolving within minutes
• Headache — reported in 10-15% of study participants, usually mild
• Water retention — peripheral edema from GH-mediated renal sodium reabsorption
• Increased appetite — attributed to GH-driven lipolysis triggering compensatory hunger signals
• Paresthesia — tingling or numbness, particularly in extremities, associated with fluid retention
• Vivid dreams — anecdotally reported, potentially related to GH-associated changes in sleep architecture

Serious concerns: Prolonged supraphysiological GH/IGF-1 elevation carries theoretical risks including insulin resistance, joint pain, carpal tunnel syndrome, and potential cardiovascular or neoplastic effects. The ConjuChem clinical program was discontinued following a subject death during trials. Long-term human safety data does not exist for CJC-1295.